Identification of Esters of Monobasic Acids by the Use of Ethanolamine WILLIAM H. RAUSCHER A N D DONALD L. MACPEEK Rensselaer Polytechnic Institute, Troy, N. Y .
T
HE successful use of ethanolamine for the identification of esters of dibasic. acids has been reported ( 2 ) . It has now
serves as a derivative for charactc.rizing thc acid. 111 ~iiost c'ascs investigated, however, a solid amide was not o1)tairied. 111 this circumstance the reaction misture is acidified with hydrochloric acid and iefluxetl it short, tinill ti) h y d ~ 1 1 amide. The liberated organic acid rmy it1 solution, or may apprar ;is nn insoluble liquid or solid. Solid acidh :ire lemovcd by filtratioii : otherffise the acid is renioved by ether estr:trtioris. Formic and hydroxy aliphatic acids could riot be rtvxvt,rtd by extractions. The acid is suhsequcntly identified through t h r x boiling or inelting point, irides of i,r:fraction, and a typical di'rivative. Results obtained by the use of the abovc p r ( i ( ~ e d i i r c\vir11 ~ a variety of esters are given in Table I. Ail nirxltiiig xiid Ix~ilirig points are corrected. The .\--B-hyilro\;~-et~i~.l uriiitles of ~ ~ i i i r i : t i i i i ( ~ acid and salicylic acid w:re found t o have the correct iiitrogtsii analyses.
been found possible to apply the procedure to esters of monobasic acids. These esters undergo rapid ammonolysis on refluxing with ethanolamine. From the reaction misture the alcohol or phenol can be distilled in a state of purity satisfact,ory for identification purposes or, if the alcohol or phenol boils clost: to or above the boiling point of ethanolamine (172" C.), it can be extracted with ether. The ether extract is washed with a small amount of water to remove traces of the alkanolamine which would otherwise interfere with the refractive index of the alcohol or phenol to be identified. During the distillation i t is possible t o make an adequate check on the boiling point of the alcohol or phenol. I n the case of a solid alcohol, distillation might not be advisable, but it can be isolated by filtration and identified in the usual way. A determination of refractive index and the preparation of a typical derivative complete the identification of this fragment from the ester.
cooled, after removal of the alcohol or phenol.
\14TEHIA LS
This amide
Table I.
of comparable purity.
Identification of Esters
Alcohol or Phenol
Ester
Isoamyl ropionate Ethyl n-Eutyrate Ethyl n-caproate Methyl n-caprylate Methyl pelargonate Methyl palmitate Methyl stearate Ethyl o-hydroxybutyrate Ethyl lactate Di-n-butyl tartrate Trieth I citrate Ethyl i e n z o a t e Iaoprop 1 benzoate Benzyl genzoate Methyl salicylate n-Butyl p-hydroxybenzoate Methyl o-chlorobenzoate Methyl anthranilate Methyl p-aminobenzoate Methyl p-toluate Methyl anisate Ethyl o-genzoylbenzoate Methyl cinnamate Ethyl cinnamate Ethyl phenylacetate Isopropyl phthalate Di-n-butyl phthalate C clohexyl acetate PKenyl acetate o-Cres 1 acetate 1-Napxthyl acetate 2-Naphthyl benzoate 2-Naphthyl salicylate Celloaolve acetate Benzyl acetate
M.P. of 3,j-Dinitrobenzoate, C. Found Lit.
Acid ____.-_____
Lit. 132 64.7
nD Found Lit. 1.4109 1.4075 1.3276 1.3288
7739.5 129-134 7.5-79 i6-79 63-65 64-68 63-64 63-68 76-78
78.'3 132 78.3 78.3 64.7 64.7 64.7 64.7 78.3
1.36'16 1.4091 1.3608 1.3604 1.3275 1.3348 1.3354 1.3354 1.3602
1 .'3610 1.4075 1.3610 ... 1.3610 1.3288 103,9-'104.4 1.3288 105.2-106.8 1.3288 ... 1.3288 ... 1.3610 ...
77-79 113-120 76-78 78-80 80-84 197-205 63.5-64.3 113-119
7R 9
-1 . 3607
1.3610
78 3 82.4 205.5 64.7 118
...
...
63,6-64.0
64.7
1,3310 1.3288
, . .
..
138.8-140.1
141
63.1-64.3 63.0-64.1
64.7 64.7
1.3292 1.3288 1.3311 1.3288
...
..
140.2-141.0
144
64-67 63.3- 6 4 . 2 76.2-78.2
64.7 64.7 78.3
1 , 3 3 0 5 1.3288 1.3346 1.3288 1.3615 1.3610
176.5-177.2 183.8-184.3 90.3-93,5
178 184.2 93-94
63,4-64.1 77.5-79 76,l-77.2 81-83.3 115-117 158-160 179-180 190-191 94.3-95.21 121.9-122.31 120.9-121.5( 135-140 198-204.2
64.7 78.3 78.3 82.4 118 161.1 182 190.8 941 1231 122.21 184.8 205.6
1,3290 1.3288 1.3602 1.3610 1.3652 1.3610 1.3770 1.3793 1.3989 1.3991
130.3-130.7
133
B.P., Found 128-132 64-66.5
O
C.
118
1.
ioS~io6 58 0 - 5 8 . 5 90.8-92.5 58.3-59.0
... ...
. . I
N-8-hydroxyethyl amide. b Isolation of acid unsuccessful. 6 Benzoic acid by oxidation of alcohol.
d
1.3598 1.3610 1.3771 1.3793 120.7-'1'21.3 1,5390 1.539g 121.1-121.4c 1.3283 1,3888 ... 1.3986 1.3891 ..
... ...
... .,. .,,
1.4'190 1,5396
...
... ... .. ,.. ...
i.'5'3'96
...
107 61 93 61 8
... ...
107 107
,..
B.P. or X1.P.. C.-. Found Lit.
...
Found ,..
Lit.
...
... .. ...
1 .'3868
61.9'62.4 62 1-62.8
fji.'4 63
1.4268
67 0 - 6 7 . 8 69.6-70.da 87.2-88.0" 93.3-94.2''
ti7
... ...
...
...
...
,.. ...
... ...
i351i42 156-164 197-204 235-240
i4i:4 164 205.4 239.3
1 .'3'8'83 1.3921 1.4171 1.4301
1 ,3979 1.4163
... ...
210:212
...
b
...
h
...
h
122 121 i
120.8-121.4 121.0-121.4 121.0-121.4
...
... ..
ziz' ...
... iii'7 121 7 121.7
...
... ,.. ,..
... .. . .
... . , , ,
.,. ...
,..
... .. ...
...
:.,
.,
,..
. .
, . .
...
izoLi2i 63.5-64.0
...
...
122' 64
... ...
...
, . .
...
, . .
... ...
...
...
iio.i~i'ii.5 i i i '
N-8-h droxyethyl phthalimide. N i t J b e n i y l ester. %.P.
923
, . .
75.&70,5
... ... ,..
... ... 120. i l i z i . 3 158,2-158.6
...
...
76.5
...
, . . , .
... ...
. I .
... ...
...
...
...
...
...
...
.,.
... ..,
... ..,
..
I . .
... ,.. , . .
i
...
112.3-114.2 150.6-151.5
,..
iii : 7 . . . 158 ... . . . . . . ...
...
163.3-'164.2"
, . .
,.. , .
M.P. of p-Broinophenacyl Ester, C. Found Lit.
... ...
..
..
...
...
..
n'D"
... , . ... ... ...
...
100.0-100.2s 100.3-101 . O a
,,,
. ... . . ... ,
127.5-'
