A STUDS' OP THE BROHIATIOlf PRODUCE

OP PESHTLMEROAPTOAGBTIC MI©

APPHOVEDs

1

7. r d-^ v <L

Professor

A S O T OF 3BB BROMimTIOH PRODUCTS

OP FHEBYLMEHC AP TOACETIC MID

THESIS

Presented to the Graduate Council of Worth

f@xas Stat# College i» Partial Pulflllraeat

«f th© K®qmir6n©jits

Fmp tb» Degree of

MASTER OF SCISHCE

ar

Clarenee William Sohia@lpf@alg Jr., B. S.

piano, Texas

August, 195$.

TABLE OP C01I2E1TS

Pag®

LIST OF TABLES , . , , i r

LIST OF ILLUSTRATIONS „ v

Chapter I. TSmmOTlOS . . . . . . '1

II, EXPERIMENTAL " . |

Preparation of Monobromo Derivative# of Phenyls©rcaptoac©tic Acid

Bromin&tion of Phanylaercaptoaoe tic Acid without Catalyst

Bromination of Phenyl®©re ap toac© tie Aeid with gat&lyst

Reactions of- Pheny1m© r c ap toac © t i c Acid Dibroraid#

Analysis Methods

III. DISCUSSIOK OF RESULTS . . 26

BIBLIOGRAPHY 27

LIST OP & B M

fablo f & m

1. Yields of Monobroaophenylaercaptoacetic Aei&s £>

2» Melting Points and Analyses of the Monobroxaophenylmercaptoacetic Acids . . » 6

3» Partition Chroma to gr aphy Column and Eluent Composition. . , , , 12

k* Eluent Systems in Adsorption chromato-graphy . . . 14

5« Heeovery of Acids in Analyses Represented in Figure 1 . . . . . . . . . . i7

It

LIST OP ILLUSSRATIQJ®

Figure Pago

1. Adsorption Analyses ©f the phenyl* mereaptoacetic Acids Rising f l uen t System fw© • # • # * * * * . * # • * # • « l 6

2« In f ra - red Absorption spectrum of Phenylmercaptoacatie Acid 19

3» In f ra - red Absorption Spectrum of o-Broraophony 1m®rc aptoace t i c Acid , , , , , 20

1 * Inf ra - red Absorption Spee truss of m-Bromophenylmerc ap toac e t i c Acid . , , , , 21

S>. In f ra - red Absorption spectrum of p-Bromoptoany lme r c ap toace t i e Acid , . , , 22

6 . Inf ra- rod Absorption spectrum of Rosidtt® • • • • • • • • • * • • « « • 23

?• In f ra - red Absorption Spectrum of a®si<tn# *B* * « • • • • • • < • » , • » « - * 2 .

CHAPTER I

IBTH0DTKJ7I OH

During the course of m investigation to determine fell®

herMcldal properties of ft series of compounds* Ashmor©

broain&ted pheny liaeroapt oac etic acid, When h» brosinated

with iron as a catalyst,, to obtained a compound which melted

at lilt? to ll£°* 'Shis coapootid was prowa to be p-broso»

phenylaercaptoacetic acid, H© obtained a iiionobroiao deriva-

tive of unknown configuration melting at 1O||.0 when he

broialnated without a catalyst. He reported this latter

cosapoxmd to be nuclear substituted because no precipitate

was obtained with alcoholic silver nitrate **-

PuBsaerer prepared a phenyliaereaptoaee tic acid dibromida

by brominating phenyliaerc ap to ace t i c acid in carbon disulfide

with anhydrous conditions below 20°. Prom this dibroa&d© he

obtained & mixture of nuclear substituted acid® melting

below 100° upon exposure to air, ©specially if the air was

moist# He reports no further purification of this mixture.

Upon treatment with a large amount of water or with water

containing potassium carbonate or sllwr oxide, phenylaul-

foacyacetie acid Melting at 116° was obtained* A produot

% i w s Ashmore, n2he Synthesis and Testing of Differen-tial Herbicides,tt (Unpublished Master*s Thesis, Department of Gheasistry, north Texas state College, I9I4.8}.

mstltiog a t 13B® lb# 1X9° believed to Is® p«broaophenylraarcapto-

acetic acid, was form6. upon heating the dibromid© precipitate

to i t s melting point

This investigation was begun in order to deterrain© the

nature o f the 10%° selling compound prepared by Ashaore moA

to determine which isomers and the i r relative ammrntm are

produced during broaination of- phenylsisre&p bo&ee t i c m Id#

the ortho- and raeta-bramophenylaeroaptoaeetie acids are not

reported in the literate*©# I t was therefor# decided to

prepare these confounds along with the para isosaer by

m&mfelguous methods i s order to compare the properties- of

Wms® acids with the products obtained from bpomliiatlon.

The possibility of an oc-bromophenjlmere&ptoacet ic aoid is

remote because t&e corresponding ooohloro acid, as prepared

by FKNaexer, decoisposed when exposed to water or air*. 3 I t

was also considered of interest to repeat sonse of the exper-

iments o f F w e r e r ,

For tii© separation of and the analysis of the products

of a brorainatlon reaction, chr oatatogr aphy and spectroscopic

analysis gave the greatest promise of success, Partition

chromatographic analysis has been utilized for the separa-

tion of and <juantltatlve estimation of acetylated amino

^Rudolph Ptoaaerer, Ber . , Ij2* 327$ (1909),

^ludolph Punsaerer, Ber., IjZ, 2282 (1909) *

k acids "by Martin and Synge,^ of water-soluble carboxylio

acids by Marvel and Rands, and of hig£i molecular weight /

fatty aeida by Ramsey and Patterson, Partridge and Brl»-

I@y7 used displacement chromatography on synthetic ion-

exshaage resins for the qualitative separation of amino

acids. A correlation between the degree of adsorption of

certain earboxylic acids on silica gel and the configura-

tions of the acids has been shown by Gyani and (jangaly «®

Williams^ predicts a correlation between the absorption

bands in th@ eight to ten and twelve to fifteen micron re-

gions and the presence of mono sub s ti fcution, or of para,

a©ta» or ortho disubstitution in the ben2ea® nucleus.

Ferguson and Levant10 have recently utilized the presence

of these absorption bands la analyzing disubstituted com-

pounds.

^A. 3* fm Martin and R. L. M. Synge, Blochem. J.» 35, 1J58 <19lp.)» ' * — w ~ * - **

fp. S. Marvel and R. D. Hands, Jr., J. As# Che®. Soe., |2, 26i|2 (1950). ~

L. Ramsey and w. 1. Patterson, J. Assoc* Official Aggy ghem., ||l {1948}. ~ • — — ~

h . X» Partridge and H. C. Briatley, Biochem. J".# kf* 153 {19515 . ' 1 ~ ^

®B. P.. Gyani and p. B. Ganguly, J. Indian Ohem. So©#-* 20, 331 ~ —

%an Zandt Willi®M# Rev, jci. inatrtoaentSii i2» 13 5, C191| ') •

. 10Lloyd II. Ferguson and Aim J. Levant, Anal* c9mm»* 21, 1510 (1951). ' ***

43H*OTR II

1XPERI MEITM*

preparation of Moaobrosao Derlyatlyea of

The prepara tions of the nionobromophenylmsreap to&ce tie

acids were carried out according to the following procedure

for the preparation of o~bronK>phenylmercap toaee t ic acid.

o-BrC$H||.IiH2 + HOBO +• HC1 > o~Br C Hj ltgO 1 -I- SHgO

o-BrO Kl lgGl + CgH OCSSK - BrC BfySCSGCgH •XS1 + 1,

o#». -BrCfcH SCSOCgH + H20 EOS, then

HOI -• 9»;

. EOH, than o-BrC IihSH f G10H2000H

: »o-: HOI

SH 4-COS +C2^0H

BrC H SOHgCOOH -f-HCl

2hirty-four grams (0.20 mole} of o-breraomiline was "

mixed wife $2 milliliters of concentrated hydrochloric acid

arid gafflslent water to effect solution. ®i© mixture was

cooled to 0° sad di&sotiaation was accomplished by adding a

ten percent solution of sodium nitride until starch-iodide

pmpes* showed an excess of nitrous &eid»

fbM resulting solution and an aqueous solution of I|B ;

grams (0,3 mole) of potassium ethyl xanthate were poured

sirault&a©ously, with stirring* into a large beaker

containing a thermometer. During t h i s time a heavy brown

o i l began to sepa ra t e . 2h© teapera ture of t h e Mixture i s

the beaker was kep t .at 60° to 80®' during the r eac t ion* Af t e r

mixing was completed, the r e a c t i o n mixture was heated to

b o i l i n g f o r s eve ra l minutes , While the mix tar® was - s t i l l

warm, 38 ' m i l l i l i t e r s of th© o i l was separa ted . I b i s o i l was

reflux®d overnigfcfc with 34 gwawi (0.6 so l e ) of potassium

hydroxide d isso lved in $0 Milliliters of alcohol sad $0

milliliters. of water* Th© mixture was d i l u t ed to lj.00 m l l l l *

l i t e r s , a c i d i f i e d , and steam d i s t i l l e d * Fourteen gross of

crude o-bromothiophenol was obtained a s a yellow l i qu id . , 1

f t » crude o-broaothlophenol was r©fluxed f o r 18 hours

with a mixture of 18.9 g^aas (0.20 aol®} of ohlopoacetlo

a c i d , 25»2 greats (O.ifO mole} of potassium hydroxide$ 100

m i l l i l i t e r s of e t h y l a lcoho l , and 100 m i l l i l i t e r s of water*

At the end of t h i s per iod the r eac t ion mixture was a e i d l f l e d

and ex t r ac t ed with e t h e r . The e ther was ex t r ac t ed with an

aqueous so lu t ion of sodium bicarbonate and t h i s f i l i a l ex~

t r a c t was a c i d i f i e d , t h i r t e e n and s i x t y - s i x hundredths grams

of erod» o-br oiaophenylmerc ap to ace t ic ac id mm obta ined, A

por t ion was r e c r y s t a l l i z e d and analyzed.

Hie percentage y i e l d s of the crude raonobroaophenyl-

mercaptoacetic ac ids are given l a $able 1 . i t iese y i e l d s are

based on- tfe© « p s » t l t y of s u b s t i t u t e d a n i l i n e u s e d .

%)* A# Shi r ley , p repara t ion mf Q&mmt® I n termed!atea,* P« 61*

TABLE 1

YIELDS OP CHUBB HOHOBROMOPHEHYXjIffilRCAFrOAOBHC ACIDS

Aeid Percent Yield

o-Broaophenylraerc ap toace tic acid 28 m-Broaophenylsisrcap to ace tic acid . * . • . » . « . . 22 p^Broisophenylia© reap toace tie acid * »-• . . . . . . . . 3

Table 2, shows the Halting points, bromine analyses* and

neutralization equivalents ©f these confounds#

TABLS 2

l®LfE»0 POI8TS AID AHAIXSKS OP fHt I«5NOBROMOPHimJMSHCAPTOACETIC ACIDS

A© id Point °G(cor.)

"liu'wail.gftSim 'S pa£?* A© id Point

°G(cor.) Calculated for SgH^OgBrS Found

mrnmtm rm Sp|%lrS Pound

Orfeo let a Para

117-0 85-0 115-6 i? n? 32.31

32.3||. 32*3i{.

32«^ 32*03 31.9®

^Determined by the Carius me Shod*

Brominatlon of Phenylaeroaptoaeetie Acid gttbout Catalyst L'""r

Pour grams (0*02t§. mole) of phenylsiereapto&eeiic acid

was dissolved in 100 milliliters of glacial acetic acid con-

tained in a 200 Milliliter flask equipped with & stirrer*

©lis solution m m cooled in an ice bath and 1 ,00 grams

(0.02k *»ole) of bromine was added slowly, fh© mixture was

allowed to warm to room temperature while being stirred and

stirring, was continued for eighteen hours.- At th® ©ad of

t h i s period unre acted bromine was blown from the solatium

using a gent le stream of a i r* Evaporation, was continued to

dryness, Hie weight of fee crude product was $*77 grams,

fkilB erode product was dissolved in 2$ m i l l i l i t e r s of

g l ao i a l acs t i c a d d and the solut ion was poured in to 100

m i l l i l i t e r s of ioe water* 4 copious whit® p r e c i p i t a t e was

produced, The p r e c i p i t a t e weighed ^,$'3 grants and upon,

rec rys t&l l i za t ion proved to Is® predominantly p-bromophenyl-

wareaptoacetio ac id ,

lisa f i l t r a t e r e s u l t i n g from the reiaoval of the p r e c i p i -

t a t e f r o a the acet ic acid-water mixture was evaporated to

dryn©sb. The r e s u l t i n g so l id was designated Residue "A1*,

Brosinat ion of Phenylaercap toacet ic kola with Catalyst

pour g ram fG.OSfj, mole) of phenylmercaptoacetic a©id

was dissolved in 100 m i l l i l i t e r s of g l a c i a l ace t i c a®id con-'

tallied in a 200 m i l l i l i t e r f l a s k ©quipped with a s t i r r e r *

0n@-tenth gram of f r e s h i ron f i l i n g s was added, This so lu-

t ion vraa cooled in an lee bath and lj.,G0 grass# ( 0 , 0 2 J f mole) of

bromine was added slowly, The mixture was allowed to warn

to room temperature while being s t i r r e d and s t i r r i n g was.

continued f o r eighteen hours. At the and of t h i s period un~

reacted bromine was blown from the so lu t ion using a gent le

stream of a i r . Evaporation was continued to dryness, The

r e s u l t i n g so l id was a dark red color because of the f e r r i c

8

bromide present. *&» solid was dissolved in eth@r and this solution was extracted with aqueous sodium bicarbonate until

ferric bromide began to appeal* in th© aqueous phase. Hie

coiibined extracts top© acidified and a whit© precipitate

'Wiping 3*2)4 grams mm removed. fhe precipitate upon re~

crystallisation proved to bo predominantly p~bro»i©pheiayl~

»©reaptoac© tie a©id* . .

fte@ filtrate resulting from the removal of the preeipi»

tat© from th© acidified extracts was ©rfepaettd with ether*

©10 e ther was evaporated sad th® resulting solid was design

n&ted Residue *8*.

°£, P aylnBTOtptottoetlo laid Pibromide

The phenyliaer capto&c©tie acid dibroa&de used la these

experiments wma prepared by the method of Puiss&erer.

Owe and ninety-five hundredths grass of the dibromide

preeipltate urns treated with 20 milliliters of cold dis-

tilled water* fh© color of the proolpitat® became white

within three minutes and the water became yellow colored,

fhe precipitate was r©moved. An effort was made to re-

erystalliz© this material from benzene but only a portion

dissolved, to benzene-soluble portion was a mixture -ffhich

aelted over the rang© 97° to 109°. a*h© benzene-Insoluble

portly was ree ry a tall i ze d f « ethyl ace tat® and the

zrmmvert Bar., J|gf 2275 (1W)

resulting white crystals melted with decomposition at" llj20.

Halogen wm absent but sulfur was pre sent in this acidic

coi^mmS, fm wmz tr&l i zation equivalent mm- Htm p#r»

c©nt sttlfas- mm ll|..3jj» ¥!km structure of this

mbl# pVQ&a&t Is m3kB&ai&*

and ninetf-ona hundredths grass of to dibroaide

jwwsipitats was treated with 20 milliliters of cold di**

tilled water in which was dissolved $ grass of potassium

carbonate • Sfa© precipitate because WHITER IBBISdiately*

Following acidification, a precipitate weighing 2»If£ grass

*as obtained,, T»o components of this precipitate were

isolated. One was p-bromophenylser capt oaoetic acid while

»th®r was the product of unknown structure utentioned in

th® previous paragraph.

Eighty-one hundredths gram of th® dibroalda precipltat©

was- heated *fc 50° to TO0 for on© hour. lydrogea brostlde was

observed being evolved. Portj-four hundredths gram of

p-broaophenjljserc&ptoacetic acid was obtained after tfire©

recrystallis&tloas of th© reaction product.

M&lYsIs Methods

JlSI chroma tographic _teb©«—-The chroma to graphic tub© waa

®ad# of pyrex glass of insld© diameter 1$ railllaietera. Hear

th® bottom was Mad® a series of Indentations for the support

of & circle of copper screen wlr» upon which was placed *

m

circle of f i l t e r paper, 3Ss© top of lis# tatm wmm f i t t ed

with a female .ball~asd~ socket gjwsnd glass joint and the

bottom of the tub© was olaotd wife a one-way stopcock,

the overall length of the tuba was 53 eentiffieters. & sal©

ball-and-socket grotmd $£*«•< Joint was used for connection

with a system whioh contained an op@n»e«d mmemtmr and ft

n#edle~valve leak and which was ooniseoted to the laboratory

air supply.. By this means a constant pressure could be

exerted upon the acKfeK&t* of the tube.

Partition chrosiatographie partition

chromatographic methods utilised wmm similar to those of

Marvel and lands,^ Ihe utilisation of partition chroma-

tography depends upon the selective distribution #f sample

between an iiiEaobile solvent phase and a mobile solvent phase

with consequent extraction of t&e sssaple with the mobile

phase,

fen grass of the iroiobile phase was mixed thoroughly

in a mortar with twenty grass® .of Jfallinckrodt Analytical

Reagent Silicic Acid (precipitated). if desired, a assail,

amount of indicator dissolved in the immobile phase was

added at this point. The raixtmr© was a lurried with $0

mlll l l l tera of the in i t ia l ©Iment and poured into, ttie

chromatographic tube, 'She tu.be containing the resulting

column was shaken gently to remove entrapped air bubbles

%farv®l and Rands, cg>. c i t .

IX

with the stopcoclc open at the bottom. His eolmon was washed

with $0 Mil;!,liters of it® Initial, la ordar t# pro-

mote equilibrium ba fcwsan the iraraobile ph&as and th© aobtX®

phase# As the last of this wash material was passing into

the colu&a&j, a small circle of filter paper was dropped jba.%®

the* tub© to eo¥@r the column* <gkm purpose of this top circle

of filter paper was to aid in the ©veil application of ft»

sast le to tha column,

A wighod sample af an acid or a Bathetic Mixture of

acids was dissolwd is m aittisw of initial elient. Just

bafor® the top of th« column became dry, th& solution of

saraple was applied to. fc£» oolus® using a pipette, Hie «©lm»

tiosa of sample was forced into the column using gentS#

pressure* Hi® ini tj al aidant was then added to tb» tub©

aboira tha column and ©Imtioit wm started using a positiT©

Tessstee of afeout IfO centimeters of mercury*. Uia collue tion

of 10 milliliter fractions of th© elust© was b@gua Ismh»

diatesly.

Ua each of the 10 Milliliter fractions w$# added 10

milliliters of neutral raothyl alcohol to increase til® solu-

bility of tha tltr&st. 2h» resulting aixtur# was titrated

with standardized tenth-nom&l sodium hydroxid© to the

phenolphthal® in end-point.*

fho <sroluui© of titraiit was plot tod against valwm of

sluate for cash 10 milliliter fraction. Proa such a graph

the region, of acid elation was easily discerimble.

X2

TABDS 3

PARTI S O I CHROMATOGRAPHY COLUMU a i d m i m m c o m p o s i t i o n

Immobile fbmm

Water

Propylene glycol

Propylene glycol

Ethylene glycol

Aeetamide#

Sluent system {applied in si* port 1(3918)

(a (b

(®)

(A)

(®) <*)

percent percent

90 percent 10 percent 85 percent 15 percent 80 percent 20 percent ?5 percent 2> percent

chloroform chloroform n-butyl alcohol chloroform and n~butjrl alcohol chloroform and n-btttyl alcohol chloroform' and n-butyl alcohol chloroform and n-butyl alcohol

n»Hex&ne saturated wife propylene glycol

Benzene saturated with propylene

Indicator

®s»

Benzene satarated with ethylene glycol

Benzene saturated with acet amide

Breasresol green made slightly baaie with

Hroatcresol green made slightly baaie with aimonla

Bromeresol green made slightly basic with smm&lm

lone

^Molten when mixed with silicic acid.

KHI graphs indies, t© 443,0.% tho acid wfts very

slowly f i w the ©olusn and a© sharp separat ion was «eli£o¥©Ni

because of the low s o l u b i l i t y of th© acids in m y of %i»

s y s t e m ©aployed. fh@ us© of an ind ica to r with thro© ©f the

e luent systems permitted the observation tha t the acid

d i f f u s e s very slowly and m a t th© i n i t i a l l y narrow band

toro&d»»s m th® acid i s w » d toward the bottom of th©

eoluiaa.

3 i s a t abu la t ion of the eoluran cosipasitions f o r

the s e r i e s of p a r t i t i o n chroaatographic analyses* i t i s to-

be noted t h a t coiaraeroial solvents were p u r i f i e d be for© bo ing

u sM as immobile phase or «latent* P u r i f i c a t i o n was necessary

to remove undesirable unsaturated or oxygenated compounds and

to rosiov© water so t h a t th© condit ions of analys is could bo

dupl ica ted.

j jgorp t le i t chromatographic ana lys i s ,—fhe jaethod of

preparing the colusa f o r adsorption ana lys is weus s imi lar to

t&B- Bisthod employed in p a r t i t i o n ehroaatogfaphy previously '

described. However# bo oasis® in. adsorption chroiaa to graphy

***• of e lu t ion depends upon the s e l ec t i ve rat© of r e -

moval of a sample which i s adsorbed to th© coluaai ma te r i a l

i t s e l f , th© use of an immobile solvent phase was unnecessary,

f$i® method of analysig of the e lua te f r a c t i o n s was saaa® a s previously described in the sec t ion on p a r t i t i o n

chromatographic ana lys i s , observation of the acid zone when

34

7ABLS k

Eumw ss:STEMS m ABSORFTEOIT mmommmmn:

System ifteaber Blment Composition,

03ft®' » * * # • • * . * • * * * F i f t y milliliter portions of: (a) 100 pftrec&t n-hexan© (b) 95 percent n-h®xsna and

5 percent chloroform (c) 90 percent n~h©xa»e and

10 percent chloroform (d) 8^ percent and

%$ p#re#at chloroform (e) 80 percent n~hexan© and

20 percent chloroform ( f ) ?5> percent n-hexane and

2> percent ohlorofora

Tm • • • • »*«**«'** Fifty m i l l i l i t e r portion® #f t, (a) 100 percent chloroform (b) 99 percent ©hlorofom and

1 percent n-bmtyl alcohol £e) 98 percent chloroform and '

2 percent n-butyl alcohol (d) 97 pwMntts chloroform and

3 percent n-bittyl ititedfal {«) 95 percent ehlorofom and

5 percent n~butyl alcohol

Ihree . . . . . . . . . . . Fiftf- milliliter portions of: (a) 100 percent ehlorofom (b) 98 percent chloroform. and

fpereeia-% * $ » * . . „ percent chloroforat and

I}, percent e ther {d} 9# percent chloroform and

o percent e ther C«) 92 percent chloroform. md

8 percent e ther ( f ) 90 percent ehlorofom and

10 percent e ther

us ing the adsorp t ion method wm pos s ib l e because the silieie

ac id beearae more t r a n s l u c e n t in th© region con ta in ing th©

ac id , fh@ correlation of the xoiwi wi th the pres&nce of m-M

w&m v e r i f i e d fey t i t r a t i o n l a every case .

Th# th ree ©luent systems used in t h i s s e r i e s of d e t e r -

minat ions are descr ibed in Table If,

System one proved, to be of l i t t l e use* Th© acid was

©luted very slowly and carried over into a l a rge mmib®r of 10

m i l l i l i t e r e l u a t e f r a c t i o n s . Syatarn two showed promise i a

that the ind iv idua l ac ids *93?© ©luted sharply a f t e r from l60

to 130 m i l l i l i t e r s of the e lua t e had been c o l l e c t e d and

t i t r a t e d , - Sue d e t e r r e n t i n using this system of graded

e l u e n t s ms t ha t each of the ac ids was ©luted over the same

range of elu&te f r ac t ion®, Qualitative information could

no t be derived nor could q u a n t i t a t i v e e s t ima t ion be made in

the case of a n i x t a r e . System th ree wm l i t t l e b e t t e r ttian

system one* system three was u t i l i z e d , however, in the

small seal© sepa ra t i on of pure a~bromophenylsiereap t o a c e t i c

ac id from an impuri ty in th© crude p r e p a r a t i o n . The impuri ty

was d i f f i c u l t l y reiaovable by r e c r y s t a l l l z a t i o n .

Figure 1 i s a coiaposite graph of the volume of t i t r a n t

p l o t t e d a g a i n s t the volus® of elu&te f o r f o u r separa te

analyses us ing e l u e n t system two# In each case the recovery

of a©id was g r e a t e r than 93 pe rcen t bu t because of the

proximity of to e l a t i o n peaks, t h i s method of ana lys ing

« mlximm of tb» ac ids was d i s c a r d s

l6

Fig. 1.—Adsorption Analyses of the Fhenylm^rcap to-acetic Acids Using Bluent system IWo.

17

fable 5 shows the mounts of th© acids added to and

recovered from the columns whose analyses ar© represented

in Pi gar© 1. fhe amount of acid added and the amount

recovered are expressed as the volume #f tltraat used In

those determinations# •

f&BIiB 5

HBCOVBHY OP ACIDS I I ABALXSSS REPB1SEITED I I FKHJBB 1

Acid "'jmmrmTm'wm&r Volume Equivalent of 0.1012 » WaOH

As&Baf of Acid " covered, fotsaaf Equivalent of 0.1012 * KaOH

Meta broao Ortho bromo Para broam Unsubstituted

1**31 i»l» Ur.12 Ull. ILl6 ml. 5-0? Ml*

4.02 «i. £.01 ml* luOO ml. 5.07 al.

Infra-red Absorption Analysis

Th© absorption spectrum of the acids in the solid state

both In the form of a paraffin oil mil between two rock

salt flats and after being melted between two rock salt

flats proved erratic and subject to misinterpretation.

Carbon tetrachloride proved unsuitable as. a solvent da,® to

lor solubility of the acids and the fact that it has a

strong absorption band at 12.5 to 13.5 microns. The acids

were sufficiently soluble in carbon disulfide, however, and

the absorption bands of this solvent at 6.56 and 25.2

aicroas did not interfere*.

18

The instrument used was a Beckman model IR-2 spectro-

photometer. For each scan the operating condi tions of the

instrument ware the same. The slit width was 0.6 millimeter

for the region 7*$ to 10 miorons and 1*2 millimeters for the

region 12 to 1% miorons, gain was operated at maximum

and the period was eight seconds. fhe metal shutter was

used during the entire scan because the glass shutter nor-

mally used at wave lengths greater than 9 microns was

broken, fhe wmm length drive was operated at low speed,

fh© same absorption cell was used for eaoh determination*

The thickness of its lead spacer was estimated to be 0,2

millimeter*

The carbon disulfide was dried and distilled. For

analysis of the pure acids, 0.05> molar solutions of each

were used. For the reference curve, carbon disulfide in

the same eell was used-* For analysis of broaination

reaction produets, saturated solutions in carbon disulfide

of each solid to be analyzed were prepared and the spec-

trum of each solution was compared to that of carbon

disulfide. A point by point quotient of the recorded

percent transmission of each sample in carbon disulfide

divided by the recorded percent transmisalon of carbon

disulfide alone wag made. Ihe results are recorded in

Figures 2, 3> k* 7«

m

«d •Hf <

#

I 5 O

& I %4 o

i 0 •H 43'

O

I m

i i # «\i *

10

?S

+4 0 <

*k4

(3)

I O 4*

til 0 &

1 & ! a# 2 i o u m »

0

*-t cr

£4 •T|-^

0

5 0

4&

6 0 H £

«d £

i

*

tjf i *

*

W «ri

a

•H O <: o

0 1 5 " & O fc

& I a i * m k u o

43 o 0 0« r j

C O «r| 4*

& 0 <| *d 1 I u n M I I

te *4 fc

22

::ss:ssssn»»=oi

23

* < *

§ *0 IB

m m %4 a

4 »

§ 4 ^

O K

3

I

M i i •

s D

&0

ft*

2k

#

U m r

m H

4$ m

§

& 0 m •a

1 3 £

4 I*

HI 1 i

• W

On the bas i s of the spect ra observed in Figures 2, 3#

and 5* c e r t a i n absorption maxima were assigned to c e r t a i n

s t r u c t u r a l c h a r a c t e r i s t i c s of the confounds. Absorption •

maxima assigned weres 7*76 microns f o r carbon hydrogen

bending; Q,3£ microns t e n t a t i v e l y f o r a ry l a lkyl t h i o e t h e r j

9*1&» 9*9&» and 12.25 microns f o r para d i s u b s t i t u t i o n j

9*80 and 13.5>0 microns f o r ortho d i s u b s t i t u t i o n j X2*9S> and

13*30 microns f o r meta diaubstifcution; and 13*60 microns

f o r the unsubs t i tu ted plpnyliaercap t oaee t i c ac id .

tfpon coa?>arisen of the spectra of Residues nA* and WB*

with the spectra of the pure acids , i t was seen tha t absorp-

t ion maxima corresponding to mono sub s t i tu t i on , para dtsubat i -

t u t i o a , and ortho d i subs t i t u t ion occur i s both , f t warn

concluded t h a t upon bromination of pbenylraercaptoaoetic acid

with and without the iron c a t a l y s t , bromination occurs both

in the ortho and para p o s i t i o n s . Usea equiiaolar amounts of

bromine and of phenylmercaptoacetic acid a w used, some

phenylmereaptoacetle acid f a i l s t o r e a c t . *rhe meta absorp-

t ion band wag not observed to the spectrum of e i t h e r les idue WAW or Residue nBn*

CHAPTER III

DISCUSSION OP RESULTS

Throughout this investigation, no 10lf° melting compound

has been detected. It must be concluded, therefor®, that

this previously reported melting point was in error or that

the material was a mixture sine# it was reported to have

depressed the melting point of authentic p-broiaophenylmer-

captoaoetlo acid,

Al though chrosa.to graphic techniques did not prove fe as-

able for qualitative or quantitative astimatlon of mixtures

of pheny laer c ap t o ace 11 c acid and Its raonobromo derivatives*

infra-red spectrophotometry did prove to be of value.

p-BroiaophenylsaerGaptoacetic acid is the chief product pro-

duced upon brominating phenylmercaptoacetlc acid without

a catalyst and with an iron carrier. A small amount of

o-bromophenylrae rcaptoacetio acid is produced but no m-brorao-

phenyliaereap tome# tic acid Is detected by infra-red methods.

It is possible that spectrophotometry could be utilized

in a quantitative determination If more narrow slit widths

could be used In our instrument so that higher resolution

would be obtained in the 12 to lif microns region.

26

BIBLIOGRAPHY

Books

Shi r ley , D, A., Preparat ion of Organic* Intermediates , Hew York, John Wiley and sons, Xne,, 1951*

Art ic le s

F@rga.so®, Lloyd H, and Levant, Alma J . , Anal, Cheia., 23, 1510 (195D.

Gyani, 1# P« and oaagaly* P, B, , J , Indian Chea. Soo*» 20, 331 (19l|.3). ' ' : "

Martin, A. J» P. and Syng®, R. L. ! • , Bioehea. J . . 35. 3353 (XgpL). ' ~

l a n r e l , c , S. a»d lands , R„ X>., J r , , J . JHt# chea, 3©e*» 72# 2oi 2 <1950). ' ~ • * -

Par t r idge , S. M. and Briraley, R, C,» Biochem, J , . k<5. 152

( i 9 5 i j » _ | ~ .

Pw®ter©r, Budolf, Bar , , ]j2, 22?£ (1909}.

Tmmmr$ Hudolf, Ber,» kZ» 2282 (1909), Ramsey, L. L, and. Pat terson, w. I . , J , Assoc, o f f i c i a l Asr.

Chea., JX, IjJjl (19%8>. ~ — ^

Williams, fan Zandt, l e v , s c i , Instruments# 19# 135#- C'19%8')-«

flfcpublishsd Mater ia l

Ashjaor®, James, "the Synthesis and fa s t ing of D i f f e r e n t i a l Herbic ides ," (Unpublished Master*s m@si» t Department of Chemistry, North Texas Stat® College, 19i{.8),

Z?