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An investigation of the oxidation of sucrose to oxalic acid by the acid and electrolytic methods

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An investigation of the oxidation of sucrose to oxalic acid by the acid and electrolytic methods

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Content AN INVESTIGATION OF THE OXIDATION OF SUCROSE TO OXALIC ACID BY THE ACID A N D ELECTROLYTIC M ETHODS A T hesis P re sen te d to the F a c u lty of th e Department of Chem istry U n iv e rsity of Southern C a lifo rn ia In P a r t i a l F u lfillm e n t of the Requirem ents fo r the Degree M aster of Science in Chemistry by E l i Simon June 1939 UMI Number: EP41509 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author. UMI EP41509 Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 This thesis, written by E li Simon under the direction of h..^:® Faculty Committee, and a p p r o v e d by all its members, has been presented to and accepted by the Council on Graduate Study and Research in partial fulfill ment of the requirements for the degree of M aster of Science Secretary June 1939 Faculty Committee Gh&lrman /O X . X edf ‘ - 't ^ ; 5 * ^ «■ { TABLE OF CONTENTS CHAPTER PAGE I . INTRODUCTION OF THE PROBLEM.............................................. 1 Statem ent of the problem ...................... 1 Importance of th e s tu d y ............................... 1 M a te ria ls used • • • • ............................ . . • • • 2 Methods p re v io u sly used. • • • • • • • • • • • 2 I I . NITRIC A C ID-SULFURIC ACID OXIDATIONS...................... 4 E xperim ental procedures and r e s u l t s . • • . • • 4 I n te r p r e ta t io n o f r e s u l t s ............................... 20 E xperim ental c a lc u la tio n s . ............................ 22 I I I . NITRIC ACID-PHOSPHORIC ACID OXIDATIONS.................. 24 E xperim ental procedures and r e s u l t s ...................... . 24 I n te r p r e ta t io n of r e s u l t s . • • • • • • • • • • 34 Experim ental c a lc u la tio n s . • • • • • • • • • • 35 IV. ELECTROLYTIC OXIDATIONS...................................................... 36 E xperim ental procedures and r e s u l t s . . . . . . 36 I n te r p r e ta t io n of r e s u l t s .............................................. 47 E xperim ental c a lc u la tio n s . . . . . . ................... 48 V. SU M M A RY A N D CONCLUSIONS...................................................... 50 BIBLIOGRAPHY............................................................................................ 52 LIST OF FIGURES FIGURE PAGE 1. N itr ic a c id - s u lf u r ic a c id o x id a tio n a p p a ra tu s. . 12 2. Carbon dioxide d eterm in atio n ap p a ra tu s . . . . . 29 3. E le c tr o ly tic o x id a tio n ap p aratu s . . . .................... 37 4. T itr a t io n curve showing the in c re ase in con c e n tr a tio n of s u lf u r ic a c id a t th e anode . . . 42 5. Q u in in e-sacch aric ac id c r y s t a l s ...................................... 33 CHAPTER I INTRODUCTION OP THE PROBLEM Statem ent o f the problem . The purpose of t h i s study i s to in v e s tig a te the n i t r i o a c id - s u lf u r ic a c id , th e n i t r i c acid -p h o sp h o ric a c id , and the e l e c t r o l y t i c o x id a tio n of su crose to o x a lic a c id , n o tin g th e advantages and d isa d v an ta g es of the methods under e x p e rim e n ta tio n , and the b e s t co n d itio n s f o r the most econom ical p ro d u ctio n o f o x a lic a c id . Importance of th e s tu d y . A procedure whereby o x a lic ac id could be made cheaper th an a t th e p re se n t time would be an a id to in d u s try due to the v a rie d usages o f o x a lic a c id . I t i s used as a "discharge*1 in c a lic o - p r in tin g and dyeing, f o r b leach in g f la x and straw , f o r w hitening l e a t h e r , fo r m etal p o lis h in g powders, f o r removing in k - s ta in s and iro n mould from c lo th , and in the la u n d rie s f o r n e u tr a liz in g and remov ing the bases formed on the washed m a te ria l as a r e s u l t of the h y d ro ly sis of the so ap s. In dyeing, i t is used as a s u b s titu te f o r cream of t a r t a r on account of i t s cheapness. In th e process of "chroming" wool, i t s u t i l i t y l i e s in i t s power to form double s a l t s and in i t s red u cin g a b i l i t y . In 1909 and 1910, r e s p e c tiv e ly , th e U nited S ta te s im ported 9,800,000, and 4,833,000 lb s . of o x a lic a c id ; where a s , in 1930 and 1935 th e y ex p o rted 21,000, and 35,000 l b s . , in d ic a tin g th e in c re ase of p ro d u ctio n of o x a lic a c id in t h i s co u n try . 2 M a te ria ls u se d . The s u lf u r ic ac id used was of a te c h n ic a l g rad e, assay in g about 90$ s u lf u r ic a c id ; chemi c a lly pure n i t r i c a c id , c o n ta in in g 70% n i t r i c a c id was used, but a te c h n ic a l grade would have been j u s t as s a tis f a c to r y , the C. P. grade being used because i t alone was a v a ila b le . A commercial form of ta b le su g ar, commercial vanadium p e n t- o x id e , and phosphoric a c id , assa y in g about 75^ phosphoric a c id and c o n ta in in g a vanadium s a l t as an im p u rity were a ls o employed in the ex p erim en ts. Methods p re v io u sly u se d . The methods used in the p ro d u ctio n o f o x a lic a c id have been numerous. The s y n th e s is of sodium o x a la te from m e ta llic sodium and carbon dioxide*1 - was e a r l y employed, and, alth o u g h o x a lic a c id can be produced by t h i s method, i t s co st would be p r o h ib itiv e . The p re p a ra tio n by the a l k a l i fu s io n of saw dust, s ta r c h , b ra n , e t c . was a t - tem pted. However, although the c o st of the m a te ria ls em ployed was low, the com plexity of th e procedure, the n eces s i t y f o r b atch o p e ra tio n , and the r e l a t i v e l y low y ie ld s p re vented the success o f th a t method. The p re p a ra tio n of o x a lic acid by the s y n th e sis of sodium form ate from c a u s tic soda and carbon dioxide*1 * was tho ro u g h ly in v e s tig a te d , and I b e lie v e th a t t h i s procedure h o ld s good p o s s i b i l i t i e s and should be on a p ar w ith a p ro p e rly conducted s u lf u r ic a c i d - n i t r i c a c id ■^"Oxalsaure,T t Ullman*s E n cyclopedia, V III, 1920. 3 o x id a tio n of su c ro se , I say " p ro p e rly conducted” because many attem p ts have been made to use t h i s method as a commer c i a l procedure f o r the p ro d u ctio n of o x a lic a c id , r e s u lt in g in poor y ie ld s due to the fo rm atio n of in te rm e d ia ry p ro d u cts and to lo s s o f n i t r i c a c id , which is the most expensive m a te ria l employed in the o x id a tio n . However, by the use of a s u ita b le c a t a l y s t , working te m p eratu re, and procedure, in te rm ed ia ry products can be p rev en ted , and the use of ab so rp tio n tow ers fo r the oxides of n itro g e n p r a c t i c a l l y e l i m inates lo s s of n i t r i c a c id , which can be used over and over a g a in . The form ation of o x a lic a c id from the o x id a tio n of carb o h y d rates by means of n i t r i c a c id a lo n e 2 was attem pted but poor y ie ld s were o b ta in ed , p robably due to the absence of s u lf u r ic a c id . The fu n g ic id a l p ro d u ctio n of o x a lic acid was a lso attem pted by in o c u la tin g s e c tio n s of p la n ts con ta in in g f ru c to s e - y ie ld in g carb o h y d rates w ith a s e le c te d a c id - producing fungus s t r a i n . ^ The German p a te n t no. 377,119 o u tlin e s another procedure f o r the la b o ra to ry p ro d u ctio n of o x a lic a c i d , 4 namely, by conducting eth ylene a t the r a te of two l i t e r s per hour in to one l i t e r o f 43-53$ n i t r i c a c id c o n ta in in g 35-50 grams o f m ercuric n i t r a t e a t 35°C. ^Chemical A b s tr a c ts . 29:2512. 3"Organic Acids by F e rm e n ta tio n ,” Chemical A b s tr a c ts , 24:2831. ^"P roduction of O xalic Acid from E th y le n e ,” Chemical A b s tr a c ts . 31:661. CHAPTER I I NITRIC ACID-SULFURIC ACID OXIDATIONS E xperim ental procedures and r e s u l t s . In Thorpe * s D ic tio n a ry of A pplied C hem istry.^ the procedure given is to add e ig h t p a r ts of n i t r i c a c id , s p .g . 1.38, to one p a r t of su g ar, to h eat the m ixture to b o ilin g and to evaporate to o n e -s ix th of th e o r ig in a l volume, w herein c r y s ta ls of o x alic a c id w i l l be o b tain ed on c o o lin g . However, o th e r p ro ced u res2 have s ta te d th a t to o b ta in maximum y ie ld s and to b e s t u t i l i z e the m a te ria ls in v o lv ed , s u lf u r ic acid must be p r e s e n t. T h erefo re, in o rd er to stu d y the n atu re of the r e a c tio n , d u p lic a te experim ents were ru n , in one le a v in g out the s u l f u r i c a c id , and in the o th e r p u ttin g i t in , to see the d i f fe re n c e s in r e s u l t s o b ta in e d . The c o n c e n tra tio n s of th e a c id s and of the c a ta l y s t were a ls o v a rie d to note t h e i r e f f e c t s on the e f f ic ie n c y of the r e a c tio n . In a l l o f the p ro ced u res, vanadium pentoxide was used as a c a ta l y s t to prevent the fo rm atio n of in te rm e d ia ry p ro d u c ts, such as sa c c h a ric a c id . To o b ta in the maximum y ie ld of c r y s t a l s , the mother liq u o r s of a l l the experim ents were co n c en trated by vacuum d i s t i l l a t i o n , the tem perature being kept below 70°C. to p rev en t decom position of the o x a lic a c id in th e s o lu tio n . X p. 729. ^U.S. P a te n t No. 2 ,057,119, Method o f producing o x a lic a c id . Ger. P a te n t No. 329,591, December 20, 1913. 5 In Experim ents 1 through 12 no a n a ly s is of the mother liq u o r or o f the p u r ity of th e c r y s ta ls was made, th ese p r e lim in a ry experim ents being run m ainly to in d ic a te the b e s t course of procedure, i t being f e l t th a t the c o n c e n tra tio n of o x a lic a c id in the mother liq u o r and the c o rre c tio n f o r the p u r ity o f th e c r y s ta ls should somewhat compensate each o th e r so th a t the r e s u l t s o b tained should be com parative. In a l l of the experim ents, continuous s t i r r i n g was employed during the a d d itio n of the m a te ria ls and throughout the e n tir e course of the r e a c tio n . Completeness of r e a c tio n was assumed when th e re was no e v o lu tio n of oxides of n itro g e n upon h e a tin g the s o lu tio n . The o x a lic acid c r y s t a l s th a t were o b ta in ed were d rie d by means of warm a i r a t a tem pera- tu re of 50-60°C. In Experim ents 1 and 2 (see page 6) e x te r n a l h e a t was a p p lie d . The r e a c tio n in both cases s t a r t e d very q u ick ly and once s ta r t e d , th e tem perature in c re a se d very r a p id ly to a maximum of 95°C ., oxides of n itro g e n being evolved. In Experim ents 3 and 4 no e x te r n a l h ea t was a p p lie d to s t a r t the r e a c tio n . The r e a c tio n tim e f o r Experiment 3 was one hour and f o r ty m inutes, whereas fo r Number 4, i t was fiv e h o u rs. A pparently, th e s u lf u r ic a c id e i t h e r a c tiv a te s the c a t a l y s t , o r of i t s e l f c a ta ly z e s the r e a c tio n . Once th e r e a c tio n s t a r t s , i t proceeds very r a p id ly by a u to -o x id a tio n , w ith an a tte n d a n t ra p id in c re ase in te m p eratu re. In a l l Table #1 Experiment number N itr ic a c id (ml.) S u lfu ric ac id (m l.) Sucrose (grams) Vanadium pentoxide (grams) _ A ctual y ie ld (gms.) T h e o re tic a l y ie ld (ekis.) P ercent y ie ld 1 3035 s p .g . 1.38 1187 sp .g . 1.28 767 3.83 198 1690 11.7 2 1000 s p .g . 1.38 -------- 230 1.15 31 508 6.1 3 3220 s p .g . 1.30 1000 s p .g . 1.28 767 1.4 211 1690 12.5 4 1090 s p .g . 1.30 -------- 230 0.46 45 508 8.85 o > 7 fo u r experim ents, a l l of the m a te ria ls were mixed to g e th e r a t the same tim e, th e re fo re th e re was no r e g u la tio n of r a te o r tem perature of r e a c tio n . A lso, in Experim ents 2 and 4, the s u lf u r ic ac id was l e f t o u t, the purpose being to note the e f f e c t of i t s absence. In Experim ents 5 through 8 (see page 8 ), a cooling b a th was used to t r y to re g u la te the r a t e o f reac tio n * How e v e r, i t was found th a t as long as a l l of the m a te ria ls were mixed to g e th e r a t one tim e, the enormous h ea t o f r e a c tio n evolved during the f i r s t f i f t e e n m inutes of th e r e a c tio n was u n c o n tro lla b le , w ith a r e s u l t a n t r i s e in tem perature to about 90°C* I b e lie v e th a t the r e l a t i v e l y low y ie ld s obtain ed in Experim ents 1 through 8 i s p a r t l y due to t h i s i n i t i a l la rg e h eat of r e a c tio n which would a c t d e s tr u c tiv e ly on th e o x a lic a c id , f u r th e r o x id iz in g i t to carbon d io x id e . Experim ents 9 and 10 (see page 9) were undertaken to determ ine i f the tem perature could be c o n tro lle d between 65-70°C. du rin g th e f i r s t f i f t e e n m inutes o f th e r e a c tio n . To do t h i s a m ixture of s u lf u r ic and n i t r i c a c id was added dropwise from a s e p a ra to ry fu n n el to a s o lu tio n c o n s is tin g of a known w eight of sucrose d iss o lv e d in a known w eight of o x a lic a c id s o lu tio n . Thus, a l l of the sucrose w ill not be r e a c tin g a t the same tim e, as p re v io u s ly , which should p re vent the la rg e i n i t i a l h e a t of r e a c tio n . Table #2 Experiment N itr ic S u lfu ric Sucrose Vanadium A ctual T h e o re tic a l P ercen t number a c id ac id (grams) pentoxide y ie ld y ie ld y ie ld ______________(ml.O__________________________ (grams) (sms.) (sms.)___________ 5 3220 s p .g . 1.30 1100 s p .g . 1.28 700 1.05 410 1550 26.5 6 1090 s p .g . 1.30 -------- 230 0.345 80 508 15.8 7 4800 s p .g . 1.30 626 s p .g . 1.28 1000 1.25 436 3540 12.3 8 2150 s p .g . 1.30 273 sp .g . 1 • 23 700 1.05 95 1550 6.2 CD 9 R eaction mix Exp, 9 Exp*10 O xalic a c i d .......................................... 671 g. 454 g. W ater................................................... 2000 ml. 1250 ml. S ucro se.............................................. 800 g . 800 g. Vanadium pentoxide . . . . . 1.2 g. 1,2 g, S ep arato ry fu n n el Time to drop a c id s i n ...................... • • • • 8 h o u rs. • • • • • T o tal r e a c tio n tim e 25 h o u rs........................ 625 ml. 2460 ml. S u lfu r ic a c id , sp .g . 1 .2 8 . . 313 ml. N i tr ic a c id , s p .g . 1 .3 . . . 3010 ml. Y ield o b tain ed • • • • • • • 600 g. 650 g. True y ie ld (600-671) g. = lo s s (650 - 454 g. of 71 g. = 196 g. T h e o re tic a l y i e l d ....................... 1768 g. 1768 g . P er cent y ie ld • • • • • • • n eg ativ e 11.1$ 10 A v ery nice re g u la tio n of tem perature was o b ta in ed , th e tem perature being kept between 60-70°C. throughout the e n tir e re a c tio n * The r e s u l t s o b tain ed o f f e r f u r th e r evidence of the f a c t th a t a la rg e excess of n i t r i c a c id makes f o r sm all y ie ld s due to the f u r th e r o x id a tio n of the o x a lic a c id to carbon d io x id e , as shown by Experiment 9, w herein not even the o r ig in a l amount of o x a lic acid in the r e a c tio n m ixture was re c o v e re d . A p o s itiv e y ie ld was o b tained in Experiment 10 due probably to the h ig h er r a t i o of s u lf u r ic to n i t r i c a c id . P revious experim ents seemed to p o in t to the f a c t th a t th e sm all y ie ld s o b tain ed were due to the la rg e excess of n i t r i c a c id . T h erefo re, in Experim ents 11 and IE (see page 11) a very la rg e excess of s u lf u r ic acid was used and the concen t r a t i o n o f the n i t r i c a c id was c u t down m a te r ia lly . The mix in the r e a c tio n k e t t l e was h eated to 60°C. a f t e r which th e mixed a c id s were added slow ly from a se p a ra to ry fu n n e l. In both Experim ents 11 and 12 v ery bad fro th in g oc cu rred as soon as the a c id in the s e p a ra to ry fu n n el was added. I b e lie v e th a t the c o n c e n tra tio n of the s u lf u r ic and n i t r i c ac id was too g r e a t, causing decom position of the sucrose w ith r e s u lt in g f ro th in g . Experim ents 13 and 14 (see pages 14, 15), s e t up as shown in Eigure 1, page IE, were run to see i f the excess s u lf u r ic ac id could be used and s t i l l p rev en t the c h a rrin g and f r o th in g th a t occurred in Experim ents 11 and 12. 11 R eaction k e t t l e Exp. 11 S ucrose, ................................ 800 g. S u lfu ric a c id , s p .g . 1 .8 3 . . . . 1850 g. S u lfu ric a c id , s p .g . 1 .4 9 .................................................. Y / a t e r . ....................................................... 2500 ml. Vanadium pentoxide ..... .. 2.0 g. S e p a ra to ry funnel S u lfu ric a c id , s p .g . 1 .8 3 . . . . 1000 g. N itr ic a c id , s p .g . 1 .4 2 . • • • • 3450 g. R esu lt . . . Decomposition experim ents Exp. 12 350 g. 3760 g. 1.05 g. 1840 g . in "both sucrose Solution c«_ ,oo r 4- V ) gn tJ ^ o d. £ 4- 0 « < L > C C L . £ £ O 3 U C L H^p Ouf _ 4 HxO & d"V K 13 A s y n th e tic mother liq u o r of o x a lic a c id was made up and a sucrose s o lu tio n and an a c id s o lu tio n were added sim u lta n e o u sly and slow ly from s e p a ra to ry fu n n e ls , dropping in the sucrose s o lu tio n a t a s l i g h t l y f a s t e r r a te than the a c id s o lu tio n . The s o lu tio n in the re a c tio n mix was h eated to 65°C. a t which time the sucrose and n i t r i c a c id s o lu tio n s were slow ly added from the se p a ra to ry fu n n e ls . The tim e ta k en to pass the s o lu tio n s in was seven h o u rs, and the t o t a l r e a c tio n time was tw e n ty -fiv e h o u rs. At the com pletion of the r e a c tio n the s o lu tio n was allow ed to co o l. The c ry s t a l s th a t se p a ra te d out were f i l t e r e d o ff and the mother liq u o r was vacuum c o n c e n tra te d . The crude c r y s ta ls were c r y s t a l l i z e d once from d i s t i l l e d w ater and d rie d w ith warm a i r a t 50-60°C. The id e n tic a l m e ltin g p o in ts of 1 0 1 .5°C. show th a t a good grade of o x a lic a c id can he o b tain ed w ith one o r two r e - c r y s t a l l i z a t i o n s , the im p u ritie s in the crude product c o n s is tin g m ostly o f excess w ater and s u lf u r ic a c id . The same r a t i o of m a te ria ls is used in both Experiment 13 and 14 except th a t in No. 14 the o x a lic a c id was om itted from the r e a c tio n mix, to note the e f f e c t o f i t s absence. A lso, in ste a d of allow ing s e p a r a te ly a s o lu tio n of sucrose and a n i t r i c a c id s o lu tio n to f a l l upon a s u lf u r ic acid s o lu tio n , the sucrose was d isso lv e d in w ater, and a mixed a c id s o lu tio n ( s u l f u r i c - n i t r i c ) was slow ly in tro d u ce d . The tem perature throughout the e n tir e tim e o f r e a c tio n , as in Experiment 13, was kept between 65-70°C. 14 E xperim ent 15 S ep arato ry S e p a ra to ry R eaction k e t t l e fu n n el #1 fu n n el #2 S u lfu ric a c id W ater—200 ml* N itr ic a c id s p .g . 1 .7 5 —1950 g. s p .g . 1 .4 2 —1560 g. Sucrose— 500 g. Oxalic a c id * — 975 g. W ater—720 ml. W ater—1800 ml. Vanadium p en to x id e—0.75 g. Weight of c r y s t a l s .................................................. .... 1525 g. P u r ity of c r y s t a l s .................................................. 88.1$ Weight o f pure o x a lic ac id . .................................. 1342 g. Volume of mother liq u o r . ................................ 1300 ml. S p e c ific g r a v ity o f mother liq u o r . . . . • • • 1.55 Weight of o x a lic a c id in mother liq u o r • . . • 79.3 g. T o tal w eight of o x a lic a c id o b tain ed = (1342+79.3) = 1421.3 g. Conversion y ie ld o f o x a lic a c id . . • = (1421.3-975) = 446 g. T h e o re tic a l y i e l d ...................• • • • • • • • • • 664 g. Per cent y i e l d ..................................................................... 67.2$ M.P. of r e c r y s t a l l i z e d o x a lic a c i d ......................... 1 0 1 .5°C. M.P. of pure o x a lic a c i d .............................................. 1 0 1 .5°C. *Whenever o x a lic a c id i s in d ic a te d , the a c id w ith the two m olecules of w ater is meant. 15 Experiment 14 Vanadium p en to x id e—0 .5 g. W ater—1680 ml. Weight of c r y s t a l s .................................................................... 146 g. P u r ity o f c r y s t a l s .................. ................................................. 90.0$ Weight o f pure o x a lic a c i d ............................. 131.4 g. Volume of mother liq u o r . • • • • • • • • • • • • • 800 ml. S p e c ific g r a v ity of mother liq u o r . • • • • • • • • 1.62 Weight of o x a lic a c id in mother liq u o r • • • • • • 85.5 g. T o ta l w eight o f o x a lic ac id o b ta in ed » (131.5+85.5) = 216.9 g. T h e o re tic a l y ie ld . • • • • . . • • • • • • • • • • 442 g. Per cent y ie ld ...................• • • • • • • • • • • 49.2$ 16 In the p rev io u s experim ents the o x a lic a c id rem qining in the mother liq u o r was c a lc u la te d as a p a r t of the y ie ld , because in a c tu a l p la n t o p e ra tio n the mother liq u o r from one b a tc h becomes the s t a r t i n g p o in t of an o th er r e a c tio n mix. Thus, the o x a lic a c id is never l o s t , the mother liq u o r ob ta in e d being always s a tu ra te d w ith o x a lic a c id , the amount contained th e r e in depending upon the c o n c e n tra tio n of s u l f u r ic acid in th e liq u o r . T h erefo re, i f one s t a r t s w ith a s y n th e tic mother liq u o r and runs only one experim ent, th e amount rem aining in i t a t the end o f the r e a c tio n must be reckoned in to o b ta in the tru e y ie ld . Experim ents 15 and 16 (see pages 17, 18) were run in p a r t to prove t h i s p o in t and in p a r t to see i f the la rg e excess of o x a lic a c id used in the r e a c tio n mix of Experiment 13 could be decreased and s t i l l o b ta in a good y ie ld . These experim ents were run under th e same c o n d itio n s as in Experiment 13. In th e c a lc u la tio n of Experiment 16 no account was taken of the o x a lic a c id rem aining in th e mother liq u o r sin ce a tr u e mother liq u o r which was s a tu ra te d w ith o x alic acid was used. Table No. 3 on page 19 shows th a t the amounts of acid in the i n i t i a l and f i n a l mother liq u o rs p r a c t i c a l l y cancel each o th e r. Hence, the 77.7 g. of o x a lic a c id i n t r o duced from the mother liq u o r of Experiment 13 i s p r a c t i c a l l y balanced by th a t rem aining in th e mother liq u o r of Experiment 16, making the c o rre c tio n f o r the d iffe re n c e , True % y ie ld = (243-2.2) x 100 = 72.4$ 331 17 E xperim ent 15 R eaction k e t t l e S u lfu ric a c id s p .g . 1 .7 5 —1100 ml. S ep arato ry fu n n el #1 S ep arato ry fu n n el #2 Sucrose— 500 g. N itr ic a c id s p .g . 1 .4 2 —1100 ml. W ater—400 ml. Oxalic a c id —1100 g. W ater—1800 ml. Vanadium p en to x id e—0.75 g. W ater—720 ml. Weight o f c r y s t a l s ...................... . • 600 g. P u r ity of c r y s t a l s .......................................... .... 79.2$ Weight of pure o x a lic a c id • • • ..................................... 475 g. Volume of mother l i q u o r ................................ .... 2000 m l. S p e c ific g r a v ity of mother liq u o r . • • • • • • • • 1.47 Weight o f o x a lic acid in mother liq u o r • • • . • • 83.2 g. T o tal weight of o x a lic a c id o b tain ed = (475*83.2) = 558 g. Conversion y ie ld of o x a lic a c id . . . = (558-110) = 448 g. T h e o re tic a l y ie ld . • • • • .............................................. 664 g. Per cent y ie ld • • • • • • • • • • ................................ 67.5$ 18 E xperim ent 16 R eaction k e t t l e Mother liq u o r from Exp. 13—1260 ml. (approx. 50$ s u l f u r ic ac id s a tu r a te d w ith o x a lic acid) S ep arato ry fu n n el #1 S ucrose—150 g. W ater—200 ml. W ater—725 ml. Oxalic a c id —55 g. Vanadium p en to x id e—0 .2 g, S ep arato ry fu n n el #2 IT itric a c id s p .g . 1 .4 2 —550 ml. Water 360 ml. Weight of c r y s ta ls ........................ • • • • • • • • • • 369 g, P u r ity of c r y s ta ls ................................................................ 80.6$ Weight of pure o x a lic a c id • • • • • • • • . • • • 297 g, Conversion y ie ld of o x a lic a c id . ................................... 242 g. T h e o re tic a l y ie ld . ............................................................... 331 g, Per cent y ie ld ...................................................... 73.1$ 19 Table #5 Volume of mother liq u o r from Experiment 13 . . . • 1360 ml. S p e c ific g ra v ity o f mother liq u o r . .............................1.55 P er ce n t by weight of o x a lic a c id . . ............................3.93 Weight o f o x a lic acid in the mother liq u o r • . ♦ • 77.7 g. Volume o f mother liq u o r from Experiment 16 # • . . 2075 ml* S p e c ific g r a v ity of mother liq u o r . • • • • » • • • 1.45 P er cent by w eight of o x a lic a c id . • • • • • • • • 2.49 Weight o f o x a lic a c id in the mother liq u o r • • • • 75.0 g. s o I n te r p r e ta t io n of r e s u l t s . The procedure which was found b e st to fo llo w is th a t o u tlin e d in Experiment 16, w herein a n i t r i c a c id s o lu tio n and a sucrose s o lu tio n are allow ed to f a l l slow ly in to a mother liq u o r mix, from sepa r a to r y fu n n e ls, the mother liq u o r assay in g about 50fo s u lf u r ic a c id and being s a tu ra te d w ith o x a lic a c id . The r a t i o o f m a te ria ls as o u tlin e d a lso seems to give very fav o rab le r e s u l t s . 1. By adding the sucrose and n i t r i c a c id s o lu tio n s slow ly in to the s u lf u r ic a c id s o lu tio n , only a very sm all p a r t of the t o t a l s o lu tio n i s r e a c tin g a t one tim e, th e re b y p re v e n tin g excessive h eat o f r e a c tio n and en ab lin g one to c o n tro l e a s ily the tem perature of r e a c tio n between 65-70°C. 2. I t is b e st to h eat the mother liq u o r to 65°C. before adding the sucrose and n i t r i c acid s o lu tio n s and then to s t i r co n tin u o u sly to p revent lo c a l r e a c tio n . 3. The use of o x a lic a c id in the mother liq u o r h elp s to slow down the r e a c tio n ; i t a lso makes fo r a s u lf u r ic a c id s o lu tio n s a tu ra te d w ith o x a lic a c id , and i t m ain tain s a reducing c o n d itio n a t a l l tim e s. 4. The use of a la rg e excess of s u lf u r ic a c id de c re a se s the amount of n i t r i c a c id needed, sin ce the s u lf u r ic a c id a c ts as a c o n c e n tra to r as the r e a c tio n pro ceed s, th e re b y p rev en tin g excessive o x id a tio n o f o x a lic a c id to carbon d i oxide . 21 5. A much g r e a te r p o rtio n of the o x a lic a c id in the s o lu tio n c r y s t a l l i z e s out when a s u lf u r ic a c i d - n i t r i c a c id m ixture is used th an when n i t r i c a c id alone i s used, the s u lf u r ic ac id d ec re asin g the s o l u b i l i t y of the o x a lic a c id . 6. The use of vanadium pentoxide as a c a t a l y s t en ab les one to c a rry on the r e a c tio n a t a r e l a t i v e l y low te m p eratu re, 65-70°C ., which i s advantageous in p re v e n tin g ex cessiv e o x id a tio n , and i t in h ib i ts the fo rm atio n of i n t e r m ediary p ro d u c ts, such as sa c c h a ric a c id . 22 E xperim ental c a lc u l a ti o n s . In a l l of the experim ents w herein th e th e o r e tic a l y ie ld of o x a lic a c id was c a lc u la te d , th e fo llo w in g e q u a tio n was used: 342 756 C13H33°11+ 7 H30 + 9 03 = 6 HsC304 - 3 H30 x y y = 756*x. where y = the t h e o r e t i c a l y ie ld of 342 o x a lic a c id , and x = th e amount of sucrose used. The precentage y ie ld was c a lc u la te d by means o f the fo llo w ing eq u atio n : Per cent y ie ld = a c tu a l y ie ld x 100 th e o r e tic a l y ie ld In those experim ents w herein o x a lic a c id v/as used in the i n i t i a l r e a c tio n mix, the tru e y ie ld of o x a lic a c id was o b tain ed by s u b tr a c tin g , from th e t o t a l w eight of o x a lic a c id reco v e re d , th e w eight of the o x a lic ac id used in the make-up of the r e a c tio n mix. In a l l of the experim ent w herein the p u r ity of the o x a lic ac id and the percentage o f o x a lic a c id in the mother liq u o r was determ ined, th e unknown was analyzed according to the o f f i c i a l m ethod,^ by t i t r a t i n g w ith a sta n d ard so lu tio n of potassium perm anganate. Experiment 13 is taken as an example (see page 23). D i l l a r d and Furman, Elem entary Q u a n tita tiv e A n a ly s is . 23 A nalysis o f C ry sta ls in Experiment 13 Weight o f sample • 0.5454 g. Volume of potassium permanganate re q u ire d . • • . • 15.58 ml. N orm ality o f potassium perm anganate. . . . • • • • 0.4895 fl. Weight o f o x a lic a c id in the sample = (15.58 x 0.4895 x 0.063) a 0.48 g. A nalysis o f Mother Liquor Volume of sample ....................................................... 25 ml. S p e c ific g r a v ity .............................................. 1.55 Volume of 0.4895 fi. potassium permanganate r e q u ir e d ........................... • • • • 49.45 ml. Weight of o x a lic a c id in the sample = (49.45 x 0.063 x 0.4895) = 1.52 g. P er cent by w eight of o x a lic a c id in th e mother liq u o r • » • • • • • ( 1.52 x 100)» 3.93$ (25 x 1.55 T o ta l w eight o f o x a lic a c id in the mother liq u o r • • • • (0.0393 x 1300 x 1.55) 5 79.3 g. CHAPTER I I I NITRIC ACID-PHOSPHORIC ACID OXIDATIONS E xperim ental procedures and r e s u l t s . In much in d u s t r i a l work, phosphoric a c id may he used in te rc h a n g e a b ly w ith s u lf u r ic a c id , A phosphoric a c id was a v a ila b le co n ta in in g vanadium as an im p u rity , the a c id assay in g about 75% phos p h o ric a c id . The experim ents from 17 through 26 were run using the phosphoric a c id in varying p ro p o rtio n s , in ste a d o f the s u lf u r ic a c id , the d iffe re n c e s in r e s u l t s being n o ted . Experim ents 17, 18, and 19 (see page 25) were run under the same co n d itio n s a s in Experiment 16. In Experiment 17 th e re appeared to be v ery l i t t l e heat of r e a c tio n . In s te a d , h ea t had t o be a p p lie d c o n tin uously, which i s the o p p o site of th e case w herein a s u lf u r ic a c i d - n i t r i c acid m ixture was u sed . At th e end of th e r e a c tio n tim e, the s o lu tio n was so viscous t h a t i t was im possible to reco v er th e c r y s ta ls by the methods o f f i l t r a t i o n a v a ila b le . In Experiment 18, the phosphoric a c id co n ten t was de crea sed by o n e -h a lf to see of a g r e a te r r a te o f r e a c tio n and a le s s viscous s o lu tio n could be o b ta in e d . The re a c tio n and s ta r t e d f a i r l y w e ll a t 65°C., having a f a i r v e lo c ity r a t e , bu t not as in te n se as when a s u lf u r ic a c i d - n i t r i c a c id mix tu re was used. When the e v o lu tio n of gases had ceased, I continued h e a tin g on a w a te r-b a th a t 65-70°C. However, in a 25 E xperim ents R eactio n k e t tle 17 18 19 Phosphoric a c id , 75$ . . . 227 ml. 113 ml. 100 ml. W ater................................ 438 ml. 438 ml. 425 ml. Oxalic a c id ......................... 42 g . 42 g. 63 g. S e p a ra to ry fu n n el #1 N itr ic a c id , s p .g . 1 .4 2 . . 183 ml. 183 ml. 225 ml. W ater. • • • « • • • • • • 120 ml. 120 ml. 150 ml. S e p a ra to ry funnel #2 S ucrose. . ....................... .... 50 g. 50 g. 75 g. W ater. 67 m l. 67 ml. 100 ml. Weight of c r y s ta ls . . . • no r e s u l t decomposed 42 g. P u r ity of c r y s t a l s • • • • 91.8$ Weight of pure c r y s ta ls . • 38.6 g . Volume o f mother liq u o r . • 215 ml. S p .g . of mother liq u o r • • 1.335 Weight o f o x a lic ac id in mother l iq u o r . • • 11.8 g. T o tal y ie ld of o x alic a c id . ................... 50.4 g. True y ie ld of o x a lic a c id . ............................ (63-50.4) T h e o re tic a l y i e l d . 166 g. P er cent y ie ld . . . . . . n eg ativ e 26 couple of ho u rs, the s o lu tio n had decomposed and caram elized. In Experiment 19, the r e a c tio n time was decreased to th re e hours to see i f decom position could be avoided. Experiment 20 (see page 27) was ru n d ecre asin g the c o n c e n tra tio n of the n i t r i c a c id and in c re a sin g the tem pera tu re of o x id a tio n to note th e e f f e c t of u sin g a hot phosphor ic a c id m ixture as an o x id iz in g ag e n t, bein g a s u b s titu te in p a r t f o r the n i t r i c a c id o m itted . A lso, the o x a lic ac id was l e f t out of the "make-up liq u o r" in the r e a c tio n k e t t l e . In Experim ent 21 (see page 27), the r e a c tio n was c a r r i e d about o n e -h a lf an hour p a st the p o in t w herein the evolu tio n of gases had ceased, causing bad decom position and ch a r r in g . This f a c t , th a t the r e a c tio n cannot be c a r r ie d very f a r p a s t the e n d -p o in t, c o n s titu te s a s e rio u s disadvantage of t h i s p ro c e ss. Experim ents 19 and 22 (see pages 25, 27) show th a t not even the o r ig in a l amount of o x a lic a c id was reco v ered . Experiment 23 (see page 28) was undertaken to see i f th e re is any r e a c tio n between the phosphoric and o x a lic a c id s w ith th e p ro d u ctio n of carbon d io x id e . The se t-u p used i s shown in F igure 2, page 29. In Experiment 24 (see page 30), f u r th e r work was done on studying the o x id a tio n of pure o x a lic a c id . A number o f experim ents were ru n to note the d iffe re n c e s in e f f e c t s p ro duced when phosphoric acid and when s u lf u r ic acid was p re se n t 27 E xperim ent R eaction k e t t l e 20 21 Phosphoric a c id , 75$ • . • 100 ml. 115 m l. W ater....................... .... • • • 425 ml. 1000 ml. O xalic a c id . . . . . . . • —— 50 g. Vanadium pentoxide . • • • ------ 0.04 g . S ep arato ry fu n n el #1 N itr ic a c id , s p .g . 1 .4 2 . • 115 ml. 130 ml. 7/ater. • • • • • • • • • 150 ml. 150 ml. S ep arato ry funnel #2 Sucrose. 75 g. 50 g. W ater......................................... 100 ml. 100 ml. Temperature of r e a c tio n . • 70-80°C. 65-70°C. T o tal r e a c tio n tim e . • 2j h r s . 6 h r s . Weight of c r y s ta ls • . . ♦ 5.0 g. decomposed P u r ity o f c r y s ta ls . • • • 89 $ Weight of pure c r y s t a l s . • 4.45 g . Volume of mother liq u o r . • 165 ml. S p.g. of mother liq u o r • Weight of o x a lic a c id • 1.52 in mother liq u o r . • T o tal y ie ld of o x a lic • 5.0 g. a c id . . ... .. . True y ie ld o f o x a lic • 9.45 g. a c id. . . . . . . . • 9.45 g. T h e o re tic a l y ie ld . . . . 166 g. P er cent y ie ld . . . . . 5.7$ 22 90 ml. 1000 ml. 50 g. 0.04 g. 130 ml. 150 ml. 50 g. 100 ml. 70-80°C. 5 h rs . 22 g. 85.7$ 18.8 g • 140 m l. 1.45 9.83 g. 28.6 g. (50-28.6) 110.5 g. n eg a tiv e £8 E xperim ent £5 Weight of U-tube plus A so arite a f t e r experim ent. • • • ................... • • • • • 7£.0790 g. Weight before the experim ent • • . . ................... 71.9570 g. Gain in w eight ..................................................................... 0.1££0 g. The g a in in w eight re p r e s e n ts the carbon dioxide evolved. T h erefo re, Per cent o x id a tio n = 3.5$ As a check, co n sid er the m a te ria l in the r e a c tio n f la s k : Weight o f c r y s ta ls th a t se p a ra te d out on co o lin g . .............................................• • • 2.38 g. P er cent p u r ity . • • • • • • • • • • • • • • • • 91.5$ Weight o f pure o x a lic a c i d ........................... . . . . £.18 g. Weight of the o x a lic a c id in the mother liq u o r . £.63 g. T o ta l w eight of o x a lic a c id reco v e re d . • • . . • 4.81 g. O rig in a l Y/eight of o x a lic a c i d . . . . . . . . . 5.00 g. P er cent o x id a tio n • • • • • • • • • • • • • • • 3.9$ ^(ir3 rH 0*H y jc * a ? ' ' v / p b j ' t.' A ™ * u 6 / C S V S 1 . 7 4 4 UDOSW '* 0 ? ar .* v * J " ^.7 ^ i/ri SQU44P luoj-f- Su U’ &Ju tp UJOJ^L ~?Q4 s y " a/i z j j -u /0$V H $ p} T S 5 S T E xperim ent 24 P a rt A B C D E E O xalic a c i d . ....................................................... 5.000 g. 5.000 5.000 5.000 5.000 5.000 S u lfu ric a c id , 50$. • . ................................ 15 ml. 15 ml. ---------- ---------- ------— 15 ml Phosphoric a c id , 70$. . ................................ ---------- 15 ml. 15 ml. 15 ml. N itr ic a c id , 70$..................................... . . . 7 ml. 7 ml. 7 ml. 7 ml. Tem perature, degrees ce n tig rad e . . . . 65-70 70-80 70-80 70-80 70-80 70-80 Weight of o x a lic a c id c r y s t a l s ................... 4.58 g. 4.60 ---------- ---------- ---------- 4.15 P er cent p u r ity .................................................. 87.8 87.2 ---------- ---------- ---------- 91.3 Weight of pure c r y s ta ls ................................ 4.03 g. 4.00 ---------- ---------- ---------- 3.78 O xalic a c id in mother l i q u o r ....................... 0.876 g. 0.882 0.051 0.0379 0.0391 1.073 T o ta l w eight of o x a lic a c id recovered . 4.906 g. 4.882 0.051 0.0379 0.0391 4.86 P er ce n t o x id a tio n .............................................. 1.9 2.36 99.0 99.2 99.2 2.8 31 in a s im ila r r e a c tio n mix. The t o t a l time of r e a c tio n was th e same f o r a l l , i . e . , th re e h o u rs. This s e r ie s of experim ents shows q uire c o n c lu siv e ly why such very low y ie ld s and even neg ativ e y ie ld s were ob ta in e d in the experim ents w herein a phosphoric a c i d - n i t r i c acid m ixture was used. However, a phosphoric a c id m ixture alone w i l l not d r a s t i c a l l y oxidize o x a lic a c id , as shorn by Experiment 23. This experim ent a lso f u r th e r p o in ts out th e s u p e r io r ity of s u lf u r ic a c id over phosphoric a c id . In P a rts C, D, and E, o f Experiment 24, th e re was a l most an immediate copious e v o lu tio n of oxides o f n itro g e n w ith an a tte n d a n t h ea t of r e a c tio n comparable to th a t when a sucrose s o lu tio n was used. A lso, no c r y s ta ls of o x a lic a c id se p a ra te d out upon cooling the s o lu tio n a t the end of the r e a c tio n . In d ir e c t c o n tr a s t, in P a r ts A, B, and F th e re was no apparent l i b e r a t i o n o f oxides of n itro g e n , in d ic a tin g th a t very l i t t l e decom position was ta k in g p la c e . A lso, th e bulk of the o x a lic a c id c r y s t a l l i z e d out upon co o lin g the s o lu tio n a t the end of the r e a c tio n . P revious experim ents have in d ic a te d th a t the n i t r i c ac id is used up in p r e f e r e n t i a l l y o x id iz in g the o x a lic a c id , i n i t i a l l y p re s e n t, or th a t formed by the o x id a tio n of su cro se, to carbon d io x id e , le a v in g in te rm ed ia ry products or hydro lyzed sucrose in the mother liq u o r . In t h i s experim ent, osazone t e s t s , F e h lin g ’s t e s t , and the t e s t fo r th e presence 32 of sa c c h a ric a c id were run on th e mother liq u o rs of experim ents 16, 17, 21, and 22. Experiment 25 Experiment Osazone F e h lin g T s In term ed iary products number_______ t e s t _______t e s t _________ (sac ch aric acid )_______ 16 n eg ativ e n eg ativ e n eg ativ e 17 n eg ativ e n egative n eg ativ e 21 p o s itiv e p o s itiv e p o s itiv e 22 p o s itiv e p o s itiv e p o s itiv e The osazones formed from the mother liq u o rs of Expe rim en ts 21 and 22 came down in two to th re e m inutes. How e v e r, I could not id e n tif y th e c r y s ta ls w ith the tru e f r u c to - sazone, t h i s perhaps being due to the presence of o th e r sub sta n c e s which a f f e c te d the s tr u c tu r e o f the c r y s ta ls formed. In the mother liq u o rs of Experim ents 21 and 22, th a t which came down a t th e end of the e x tr a c tio n p ro cess fo r sa c c h a ric acid-1- was a mix tu re of syrup and c r y s t a l s . I t was thought th a t the syrup was the d l form of sa c c h a ric a c id . T h erefo re, a d e riv a tiv e of the m ixture with quinine hydro c h lo rid e was made and i t s m e ltin g p o in t determ ined. Experiment 21 Experiment 22 M elting p o in t 178°C. 176°C. I was not able to fin d th e m e ltin g p o in t of the d e riv a tiv e of the d l form of sa c c h a ric a c id with quinine h y d ro c h lo rid e . The m e ltin g p o in t of the d e riv a tiv e o f the d form is 174°C. ^A lfred H. A lle n , Commercial Organic A n a ly s is . p. 215. 33 The c r y s ta ls were n e e d ie -lik e in form as shown in Figure 5. F igure 5 34 I n te r p r e ta t io n of r e s u l t s # I b e lie v e th a t the r e s u l t s o b tain ed in Experim ents 24 and 25 are s ig n i f ic a n t in th a t th e y tend to emphasize the g r e a t advantage of using a s u lf u r ic a c i d - n i t r i c a c id m ixture due to i t s s e le c tiv e n e s s of o x id a t io n , i . e . , p r a c t i c a l l y n o n -o x id atio n of o x a lic a c id and non-form ation o f in te rm e d ia te s . Whereas, when a phosphoric a c i d - n i t r i c a c id m ixture is used, severe o x id a tio n of o x a lic a c id to carbon dioxide o ccu rs, and the fo rm atio n of i n t e r m ediary p roducts i s more p re v a le n t. I t i s tr u e th a t no r e a c t io n was o b ta in ed by the mother liq u o r of Experiment 17, w herein a phosphoric a c i d - n i t r i c a c id m ixture was used, w ith E e h lin g ’s s o lu tio n , but I b e lie v e th a t t h i s is due to the f a c t t h a t a la r g e r amount of phosphoric a c id and n i t r i c acid was used r e s u lt in g in a more complete o x id a tio n . However, t h i s does not in d ic a te a g r e a te r y ie ld of o x a lic a c id , b e cause even i f more o x a lic a c id i s formed, in a l l p r o b a b ility i t w i l l be o x id iz ed to carbon dioxide by the excess phos p h o ric and n i t r i c a c id s . T h erefo re, a n i t r i c acid -p h o sp h o ric a c id m ixture i s not s u ita b le as an o x id iz in g agent in the o x id a tio n of sucrose to o x a lic a c id because i t i s "n o n -se le c - tiv e " as f a r as t h i s r e a c tio n i s concerned, o x id iz in g o x alic a c id as f a s t o r f a s t e r th a n a sucrose s o lu tio n . 35 Experim ental c a l c u l a t i o n s . E x ac tly the same p ro ce dure was follow ed as in the n i t r i c a c id - s u lf u r ic a c id o x id a ti o n s . The method of c a lc u la tio n fo r Experiment 23 i s as fo llo w s : 126 88 H2C2°4 ' 2 H2° i °2 = 2 C03 ■ * " 3 H2° X z 5 x 88 = 3.49 g. = the w eight of carbon dioxide 126 th a t should be o b tain ed from 100$ o x id a tio n of fiv e grains of o x a lic a c id . Amount o f carbon dioxide e v o l v e d ...................... • p . 1220 grams T h e re fo re , Per cent o x id a tio n = 0.1220 x 100 = 3.5$ 3.49 A nalysis o f mother liq u o r The mother liq u o r was d ilu te d to 100 ml. and a 10 m l. sample was ta k e n f o r a n a ly s is . Volume of 0.5010 fi. potassium permanganate re q u ire d . • 8.35 ml. Y/eight of o x a lic acid in mother liq u o r . • (8.35 x 0.063 x 0.5010 x 10) = 2.63 «. CHAPTER IV ELECTROLYTIC OXIDATIONS E xperim ental procedures and r e s u l t s . The e l e c t r o l y t i c o x id a tio n of sucrose was th e n attem p ted , th e th e o ry being th a t by dropping a sodium n i t r a t e s o lu tio n in to the cathode compartment c o n tain in g s u lf u r ic a c id , n i t r i c a c id would be formed which would th en be e le c tro ly z e d , th e n i t r a t e ion tr a v e lin g to th e anode. The anode compartment co n tain s a sucrose s o lu tio n d isso lv e d in s u lf u r ic a c id . T herefore, th e n i t r i c a c id formed, as a r e s u l t of the l i b e r a t i o n of n i t r a t e ions a t the anode, should a c t as an o x id iz in g a g e n t, o x id iz ing the sucrose to o x a lic a c id . A lso, th e n itr o u s oxide lib e r a te d as a r e s u l t of t h i s o x id a tio n can be f u r th e r o x i dized back to n i t r i c oxide by the n ascen t oxygen lib e r a te d a t the anode, t h i s r e a c tio n th e re b y having p o s s i b i l i t i e s of being undertaken w ith a v ery sm all i n i t i a l amount of soidum n i t r a t e . The se t-u p used i s as shown in F igure 3, continuous s t i r r i n g being m aintained in both the anode and the cathode com partm ents• Experim ents 26, 27, 28, 29, and 30 were undertaken to ac q u ain t m yself w ith some o f the p e c u l i a r i t i e s of th e r e a c t i o n , to note the s e v e r ity of th e decom position of an o x a lic a c id s o lu tio n , to note the e f f e c t of e l e c t r o l y t i c a c tio n on Fi<j. 3 tidUQs S o l u t i o n 6 o c r o s e Solu-t-ioo constant- Level H ^ o- Bat-h r t - Electric Hecrvcr 38 a s u lf u r ic acid s o lu tio n of su c ro se , and to note the r a te a t which th e c o n c e n tra tio n of s u lf u r ic a c id in c re a se s a t the anode. Experim ents 26 and 27 (see page 39) were undertaken to stu d y the e f f e c t of e l e c t r o l y t i c a c tio n on pure o x a lic a c id . In Experim ents 28 and 29 (see page 40) , a s u lf u r ic a c id s o lu tio n of sucrose was e le c tr o ly z e d , th e sucrose s o lu tio n being added dropwise to the anode compartment from a s e p a ra to ry fu n n e l. Severe decom position w ith bad fro th e in g o ccurred in Experiment 28, th e cause probably heing due to too stro n g a s u lf u r ic a c id s o lu tio n . In E ^ e rim e n t 29 the c o n c e n tra tio n of the s u lf u r ic a c id w a sm a te ria lly d ecreased. No c r y s ta ls se p a ra te d out on co o lin g of th e anode liq u o r . This liq u o r was then d ilu te d to 250 m l. and a 25 m l. p o rtio n was t i t r a t e d a g a in s t a sta n d a rd s o lu tio n of potassium perm anganate. A very d e f in ite re d u c tio n of the potassium permanganate s o lu tio n took p la c e , but t h i s red u cin g a c tio n was found to be due to the presence of in v e rt su g ar, which was formed as a r e s u l t of the h y d ro ly sis o f the su c ro se . The presence of the in v e rt sugar was shown by the form ation of glucosazone and by the re d u c tio n of F e h lin g ’ s s o lu tio n , o x a lic acid g iv in g n eg a tiv e t e s t s in both of these r e a c tio n s . 39 Cathode S u lfu r ic a c id , s p .g . 1.50. . . . . . S u lfu ric a c id , s p .g . 1 .1 8 . • • • • • Anode S u lfu ric a c id , s p .g . 1 .5 0 . . . . . . S u lfu ric a c id , s p .g . 1 .1 8 . • • • • • O xalic acid• • • • • • • • • • • • • Vanadium pentoxide ..................................... Temperature o f r e a c tio n (anode c e l l ) .......................................... 50-55°C. R eaction tim e. ................................. . 3 h r s . V o ltag e. • • • • • • • • • • • • • • 6 v o lts C u rre n t.......................• • • • ...................... 0 .5 amp. Weight of o x a lic ac id th a t se p arate d out of anode c e l l • • • • • • • 2.215 g. P er cent p u r ity of c r y s t a l s . . . . . 90.8$ Weight of pure o x a lic a c id . . . . . 2.011 g. Weight of o x a lic a c id in the mother l i q u o r ............................... . 5.396 g. T o ta l w eight o f o x a lic acid reco v ered . . . . . . ................... 7.407 g. P er cen t o x id a tio n of the o x a lic a c i d ......................................... 35.9$ Exp. 36 600 ml. 110 ml. 10.000 g. Exp. 37 500 ml. 110 ml. 10.000 g. 0 .0 2 g. 50-55°C. 3§- h r s . 6 v o lts 1 .5 amp. 3.490 g. 92.2 $ 2.296 g . 4.148 g. 6.444 g. 35.6$ Gatliode Exp. 28 S u lfu ric a c id , s p .g . 1 .5 0 ........................ 500 ml. S u lfu ric a c id , s p .g . 1 .1 8 . . . . . . -------- Anode S u lfu ric a c id , s p .g . 1 .5 0 ........................110 ml. S u lfu ric a c id , s p .g . 1 .1 8 . . . . . . -------- Sucrose d isso lv e d in 15 m l. w a te r. . 15.00 g. Vanadium pentoxide • • • • • • • • • 0.02 g. Temperature of r e a c tio n (anode cell). . . . ....................... 50-55°G. R eaction tim e ...................................................1§ 3irs. V o lta g e .............................................. 6 v o lts C u rre n t............................................................... 1.5 amps. Experiment 50 V o lta g e................................................................ .... C u rren t. * ......................................................................... Volume of s u lf u r ic a c id in anode s e c tio n . . . . S p.g. of s u lf u r ic a c id .. .. . .. ........................ Temperature in anode c e l l ................................................... Exp. 29 500 ml. 110 ml. 10.00 g. 0.02 g. 50-55°C. 3 3irs. 6 v o lts 1.5 amps 6 v o lts 1 .5 amps 145 ml. 1.18 50-55°C. 41 In Experiment 30 (see page 4 0 ), th e r a te a t which the c o n c e n tra tio n of s u lf u r ic a c id in c re ase d a t th e anode, due to e v a p o ra tio n e f f e c t s and to e l e c t r o l y t i c a c tio n , was no ted . A o n e -h a lf ml. sample was withdrawn ev ery o n e -h a lf hour and was d ilu te d w ith 50 ml. o f d i s t i l l e d w a te r, which was then t i t r a t e d a g a in s t a standard s o lu tio n of sodium hydroxide (0.1278 N .) , m ethyl orange being used as an in d i c a to r . The r e s u l t s o b tain ed are shown by th e graph in Figure 4, p. 42. As s ta te d in Experiment 29, the sucrose s o lu tio n is h y d ro liz e d , form ing in v e rt sugar which e x e rts a red u cin g a c tio n on potassium permanganate s o lu tio n . T h erefo re , to make a c o rre c tio n f o r t h i s in th e t i t r a t i o n of the unknown s o lu tio n in determ ining the amount of o x alic a c id formed, i t was n ec essary to o b ta in the equivalence of a stan d ard in v e rt sugar s o lu tio n in term s of a sta n d ard potassium p e r manganate s o lu tio n . Thus, by knowing the e q u iv a le n t of the cuprous oxide, formed as a r e s u l t of the reduoing of F e h lin g ’s s o lu tio n , in term s of in v e rt su g ar, a c o rre c tio n can be made f o r the presence of red u cin g sugars in the mother liq u o r . Of co u rse, th e assum ption has to be made th a t the only r e ducing sugars p re se n t are eq u al q u a n titie s of glucose and f r u c to s e , in v e rt su g ar, which I b e lie v e t o be a reasonable assum ption. T itrd tio n Curve. Showing In crea se In Concentre*/von O f 3u Jfu rtc A c id A t The Anodo. Ttc^. Jf l e g e n d C u rren t - /• 5 Simp Vo/fct^e - 6 ro/f s / z 'r -7 samples were W//h dr a t/n on d fi tr a feu sga / n > f~ Sfdnoarci N a Oft m /. A /aO ti T/me (hr.) . ¥ O 1 > 7 * * O Z8-** 3 /*70 ,*f'G 3V-73 Tim e in hours 43 The stan d ard in v e rt sugar s o lu tio n was made up by d is s o lv in g 1.35 g. of C. P. anhydrous dextrose and 1.25 g. of C. P. fru c to se in d i s t i l l e d w ater and d i lu t in g to 250 ml. To 10 ml. o f th e sta n d a rd red ucing sugar s o lu tio n were added 200 ml. of d i s t i l l e d w ater and 5 ml. of co n cen trated s u lf u r ic a c id , th e r e s u ltin g s o lu tio n then being t i t r a t e d a g a in s t a stan d ard so lu tio n of potassium perm anganate. I t was found t h a t , when t i t r a t i n g a s o lu tio n c o n ta in ing red u cin g sugars a g a in s t a potassium permanganate s o lu tio n , a much b e t t e r en d -p o in t could be obtained by keeping a burner under th e s o lu tio n co n tin u o u sly w hile t i t r a t i n g . Volume of 0.2800N. potassium permanganate r e q u i r e d .. 8;75 ml. T h e re fo re , 8 .75 = 0.875 m l. of KMhO^ (0.2800 N.) i s e q u i- 10 v a le n t to 1 ml. of my standard s o lu tio n o f in v e rt su g ar, which co n tain s 2.5 - 0.0100 g. in v e rt sugar per ml. of s o lu - 250 t i o n . Note th a t the y ie ld s as o b tain ed in Experim ents 31 and 32 (see page 44) are had by assuming th a t a f t e r making a c o rr e c tio n f o r the in v e r t sugar in the liq u o r,, the r e s t o f the red u cin g a c tio n on the potassium permanganate s o lu tio n i s due to the presence of o x alic a c id . Whether or not th is i s a reaso n ab le assum ption I am not su re , as th e re may be in te rn e d ia r y p ro d u cts th a t a c t lik e o x a lic a c id , but t h i s was the only procedure th a t I could conceive t h a t would e - nable me to g ain an in s ig h t in to what was happening. 44 Cathode Exp, 31 Exp, 52 S u lfu ric a c id , s p .g . 1 .1 8 . . . . . . 500 m l. ----- S u lfu ric a c id , s p .g . 1 .2 2 . • • • • • --------- 500 ml. Sodium n i t r a t e . . . . . 25.0 g. d isso lv e d in 50 ml. w ater Anode S u lfu ric a c id , s p .g . 1 .1 8 . • • • • • 110 m l. 8 ----- S u lfu ric a c id , s p .g . 1 .2 2 ....................... ................ 110 ml. S ucrose....................... .... 15.0 g. d isso lv e d in 15 m l. w ater Vanadium pentoxide ...................0 .03 g . 0.03 g. Time tak en to drop sodium n i t r a t e s o lu tio n in • • • • • • • • • • T g- h r s . 1 h r . R eaction tim e. • • • • • • • . • • • 2 h r s . 2-J h r s . Temperature (anode c e ll) . . . . . . 50-55°C. 60-65°C. V o ltag e....................... .... 6 v o lts 5 v o lts C u rre n t................................................................ 1 .7 - 1 .8 amp.1 .8 -1 .9 amp. Weight of o x a lic a c id in the anode liq u o r* . . . . . . . . . 7.27 g. 7.06 g . T h e o re tic a l y ie ld . ................................ 33.2 g. 33.2 g. Per cent y ie ld 21.9% 21.2% *For th e c a lc u la tio n o f, see s e c tio n on Experim ental C a lc u la tio n s . 45 In Experiment 33 (see page 46) the tem perature o f th e re a c tio n was in c re a se d to 70-75°C. Extrem ely bad decomposi t io n and ch a rrin g occurred* Experim ents 34 and 35 (see page 46) were perform ed usin g a la r g e r c y lin d r ic a l tube as the anode, the c y lin d e r b ein g of medium p o ro s ity . However, th e d i f f i c u l t i e s w ith t h i s c e l l v/ere in c re a se d r a th e r th a n r e medied, because th e c e l l w a ll was even th ic k e r than p re v io u s l y . I b e lie v e t h a t the tube o ffe re d so much r e s is ta n c e to th e passage o f ions th a t th e sucrose s o lu tio n decomposed b efo re adequate o x id a tio n had tak en p la c e . In Experiment 35 decom position occurred a f t e r th e r e a c tio n was stopped in s te a d of during the r e a c tio n . T his may have been due to th e in c re a se in c o n c e n tra tio n of the s u lf u r ic a c id a t th e anode, which may become q u ite a p p re c ia b le , as shown by Experiment 30. 46 Cathode Exp. 55 Sxp, 54 Sxp. 55 Sodium n i t r a t e . . . * 25 g. in 150 g. in 75 g. in 50 ml, w ater 250 ml. w ater 200 ml. w ater S u lfu ric a c id . . . . . 500 ml. 275 ml. 350 ml. s p .g . 1.18 s p .g . 1.84 s p .g . 1.84 W ater..................................... ................ 5 0 0 m l. 600 ml. Anode S u lfu r ic a c id . • • • • 110 ml. 410 ml. 200 m l. s p .g . 1.18 s p .g . 1.84 s p .g . 1 .4 W ater. • • • • • • • • -------- 750 m l. 1000 ml. S u cro se............................... . 15 g. in 50 g. in 50 g. in 15 m l. w ater 60 m l. w ater 75 m l. w ater Vanadium pentoxide ♦ . 0.10 g. -------- p . 2 g. V o ltag e...................... . 6 v o lts 6 v o lts 6 v o lts C u rren t. • • • • • • • 1 .9 -2 .0 amp. 2.5 amp. 2.0 amp. R eaction tim e ....... 1 -J- h r s . l j h r s . 1 -g - h r s . R esu lt ...................Decomposition in a l l th re e cases 47 I n te r p r e ta t io n of r e s u l t s . The d i f f i c u l t i e s th a t are p re s e n t in t h i s type of o x id a tio n r e l a t e to the p re v e n tio n of th e lo s s of o x a lic a c id , due to the decom position by e l e c t r o l y s i s , to the d i f f i c u l t y of m a in ta in in g a f a i r l y c o n sta n t s u lf u r ic a c id c o n c e n tra tio n , and to the p re v en tio n of the c h a rrin g of the sucrose in th e s o lu tio n . The c e l l t h a t was used in th ese experim ents r e a l l y did not give t h i s a f a i r chance, as the c e ll w a ll was too th ic k and dense, th e re b y p rev en tin g adequate passage of ions in to th e anode s e c tio n . U n fo rtu n a tely , a more porous type of c e l l could not be o b ta in ed , as t h a t tjrpe i s made in very sm all u n its only, which are inadequate f o r the se t-u p which I used. In a l l p r o b a b ility a s p e c ia l c e l l could have been c o n s tru c te d , but i t s p ric e would have been p r o h ib itiv e . However, th e th e o ry of th e r e a c tio n i s good and i t seems to have p o s s i b i l i t i e s . 48 E xperim ental c a lc u l a ti o n s . The d eterm in atio n of th e p u r ity of the o x a lic acid was c a lc u la te d in th e same way as in the s u lf u r ic a c i d - n i t r i c a c id experim ents. The sodium hydroxide used in Experiment 30 was s ta n d ard ized by t i t r a t i n g a g a in s t a sta n d a rd h y d ro c h lo ric a c id s o lu tio n . The fo llo w in g i l l u s t r a t e s th e method by which the amount o f o x a lic a c id in the anode liq u o r in Experim ents 31 and 32 was c a lc u la te d : Experiment 51 The s o lu tio n in the anode c e l l was d ilu te d to 250 ml, and a 10 ml. p o rtio n was taken to determ ine th e amount of in v e rt sugar present.-** Weight of CugO o b ta in e d . 0.9534 g. By Munson and W alker’s t a b l e , 2 0.9534 g. Cu20 is approxim ately e q u iv a le n t to 0.472 g. in v e rt sugar. T h erefo re, O 4-7? Z 4-7 P . 0!0100* * (* see page 43) And, 47.2 x 0.875 = 20.65 m l. 0.2800 N. KMh04 2 = the e q u iv a le n t of the in v e rt sugar in 5 ml. of the anode liq u o r . T i t r a t i o n o f the s o lu tio n in the anode c e l l v/ith a stan d ard s o lu tio n of potassium perm anganate: ^ O ffic ia l Methods of A nalysis of th e A.O.A.C., 1935. p . 479. 2 r b i a . . p . 6 3 i . 49 Volume of sample • • • • • « ................................ • • • • • 5ml* Volume of 0,2800 N. potassium permanganate re q u ir e d . ........................................... 28.95 ml. T h erefo re, (28.95 - 20.65) = 8.30 ml. 0.2800 N. KM1 O 4 , wili° k i s due to the o x a lic a c id in th e s o lu tio n . T o ta l volume of the s o lu tio n in the anode c e l l . • 250 ml. One ml. of 1 N. K M 1 1 O 4 s o lu tio n = 0.063 g. H2C2O 4 • 2 HgO T h e re fo re . ( 250 x 8.50 x 0.2800 x 0 .0 6 5 )" 7.27 g. 5 = the w eight of the o x a lic a c id in the s o lu tio n in th e anode c e l l . CHAPTER V SU M M A RY A N D CONCLUSIONS An in v e s tig a tio n of the s u lf u r ic a c i d - n i t r i c a c id , th e phosphoric a c i d - n i t r i c a c id , and the e l e c t r o l y t i c oxida tio n of sucrose to o x a lic a c id was made. The r e s u l t s o f the experim ents in d ic a te d the s u lf u r ic a c i d - n i t r i c a c id procedure to be th e most prom ising. Experiment 16 i s r e p r e s e n ta tiv e of t h is method. A n i t r i c a c id s o lu tio n alone would n o t be s u i t a b l e , due to th e f a c t th a t the o x id a tio n is c a rrie d too far, r e s u ltin g in low y ie ld s . The presence of s u lf u r ic a c id a c ts as a p ro te c tiv e ag e n t, p re v en tin g excessive o x id a tio n of th e o x a lic a c id , as a c o n c e n tra to r as the r e a c tio n p ro ceed s, and causes the p r e c i p ita t io n of th e bulk o f th e o x a lic &cid in s o lu tio n due to i t s r e l a t i v e i n s o l u b i l i t y in s u lf u r ic a c id . In t h i s type of o x id a tio n , i t is b e s t to add th e sucrose s o lu tio n and n i t r i c a c id s o lu tio n s e p a ra te ly and slow ly to the r e a c tio n mix, th e re b y en a b lin g an easy c o n tro l of the tem perature and r e a c tio n r a t e , and p re v e n tin g ex cessiv e o x id a tio n of the o x a lic a c id from o c c u rrin g . The s u b s t itu ti o n o f phosphoric acid f a i l s in t h i s type of r e a c tio n because a phosphoric a c i d - n i t r i c a c id mix tu re r e a c ts w ith o x a lic a c id w ith as much ease as w ith a sucrose s o lu tio n , r e s u lt in g in very sm all and even n egative 51 y ie ld s . A lso, i f tlie re a c tio n i s c a rr ie d v ery f a r p a s t th e e n d -p o in t, severe decom position o f the sucrose occu rs. With the p ro p er design of c e l l so th a t th e re would be a fre e flo w of ions and so th a t the c o n c e n tra tio n of th e s u lf u r ic a c id in th e anode would be kept approxim ately con s ta n t, the e l e c t r o l y t i c type of o x id a tio n has p o s s i b i l i t i e s of fin d in g a p p lic a tio n . BIBLIOGRAPHY BIBLIOGRAPHY A lle n , A. H ., Commercial Organic A n a ly s is , p. £15. B e ils te in , System No. 152-194, p. 503. Chemical A b s tra c ts , Vols. 9, p. 33302 14, p. 3 1 5 # 15, p. 21014 15, p. 25456 16, p. 1055 16, p. 5665 16, p. 11002 18, p . 15649 19, p . 31592 20, p. 23121 24, p. 28317 24, p . 45277 27, p. 25765 28, p. 67039 29, p. 25125 30, p. 25125 30, p. 82476 31, p. 74011 O ff ic ia l Methods of A nalysis of the A._0.A.£., 1935. Thorpe, D ic tio n a ry of A pplied C hem istry, pp. 729-730 "O xalsaure, ” Ullman*s E n cyclopedia. Vol. 8 , 1920. W illard and Eurraan, Elem entary Q u a n tita tiv e A nalysis P a te n ts 53 England, No. 1824, L ifso h u tz , A.D. 1891. England, No. 28,077, A.D. 1902. Germany, No. 329,591, V a le n tin e r and Schwarz, Dec. 20, 1913. U nited S ta te s , No. 1,157,348, Oct. 19, 1915. U nited S ta te s , No. 2,057,119, O ct. 13, 1936.

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Asset Metadata

Creator Simon, Eli (author)

Core Title An investigation of the oxidation of sucrose to oxalic acid by the acid and electrolytic methods

Degree Master of Science

Degree Program Chemistry

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag chemistry, inorganic,OAI-PMH Harvest

Language English

Contributor Digitized by ProQuest (provenance)

Advisor Vivian, Robert E. (committee chair), [illegible] (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c17-787980

Unique identifier UC11348405

Identifier EP41509.pdf (filename),usctheses-c17-787980 (legacy record id)

Legacy Identifier EP41509.pdf

Dmrecord 787980

Document Type Thesis

Rights Simon, Eli

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

Repository Name University of Southern California Digital Library

Repository Location USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA