Thin-layer chromatography of vinyl monomers based on undecenoic acid

‘NOTES l WROM

543 34.39

‘Thin-layer

chromatography

of vinyl monomers

based on undecenoic acid

A variety of vinyl monomers derived from undecenoic acid, a pyrolysis product *of castor oil, and its derivatives have been prepared in this laboratoryl. We now report the separation by thin-layer chromatography (TLC) of six such vinyl monomers, each representative of one of the following groups: ally1 ester (R-CO-OCH&H=CH,), .allyl ether (ROCH,CH=CH,), vinyl ester (R-CO-OCH=CH,), vinyl ether (ROCH= CH,), acrylic ester (RCH,-0-CO-CH=CH,), an d methacrylic ester (RCH,-O-COC(CH,) =CH& Materials

and

methods

Ally1 undecenoate was prepared by direct esterification of the acid with ally1 .alcohol in the presence ,of catalytic amounts of $-toluenesulphonic acidg. Ally1 undecenyl ether was obtained by condensation of the sodium alkoxide of undecenol with .allyl bromide 1. Vinyl undecenoate and vinyl undecenyl ether were .prepared by the .familiar vinyl ester interchange3 and transethertication techniques*, respectively. Undecenyl acrylate and undecenyl methacrylate were ,prepared by ‘REWBERG’S procedures, involving alcoholysis of methyl acrylate or methyl methacrylate in the presence of an ,acidic catalyst and a polymerisation :inhibitor:, :., ; ‘. ’ : Using a thintlayer applicator (Desaga, l!@idelberg), glass plates (20, ‘x. ho cm) were coated as usual with a well-stirred suspensionof SilicaGel G :(E.“Merck, :Darmstadt ; 30 g in 60 ml water) to give a layer approximately 27,,u in thickness. The plates -were dried and preserved in a desiccator. For reversed-phase TLC, .the dried, coated

g the position of six vinyl monomers and a synthetic mixture of .,these on direct plate. ,thc solvent system being n-hexane-cther (94 : 6, v/v) ; from left .to right : ally1 undecenoate, uncleccnyl acrylate, undccenyl methacrylate, ‘synthetic mixture, vinyl undecenoate, dlyl undccenyl ether and vinyl undecenyl ether. . .

J. Chronzatog.; 34 (1968)

543-545

544

NOTES

.@x-tewas uniformly impregnated with silicone oil (Dow Corning, silicone fluid 200) by allowing a 5 0/o solution in diethyl ether to ascend the plate in a developing chamber. Argentated plates were obtained by’ uniformly spraying a 12% solution of silver nitrate in aqueous alcohol (50%) on the direct plate. The direct and reversed-phase thin-layer plates were charred with chromic acid while the argentated plates were charred with concentrated sulphuric acid. Rewlts

and disczcssion Fig. I shows the positions of the ‘six monomers and that of a synthetic mixture of these on a direct thin-layer plate when developed in a H-hexane-ethyl ether (94:G, v/v) system. ‘While the undecenyl vinyl ether and undecenyl methacrylate were resol-ved individually, ally1 undecenoate and undecenyl acrylate, and the vinyl undecenoate and ally1 undecenyl ether, resolved as pairs, The Rp’ x IOO values for ally1 undecenoate, undecenyl acrylate, undecenyl methacrylate, vinyl undecenoate, ally1 undecenyl ether and vinyl undecenyl ether were 41, 41,46, 52, 53 and 65, respectively. ’ IFig. 2 shows that clear resolution between vinyl undecenoate and ally1 undecenyl ether could acetonitrile-acetic ; ‘.,, I. I, ..,.

Fig.

be achieved on the ‘siliconised acid-water (70: 15 :15, v/v/v). .‘-. .,. .“. .“‘,,

plate,

The

RF

x

systenl being IOO values for ally1

.

:

Chromatogram showing the position of ally1 undecenyl (ri&f) and their synthetic mixture (centre) on a siliconised plate, nitrile-acetic acid-water (70: 15 : 15, v/v/v). . . :‘, Fig. 3. Chromatogram showing .the position of ally1 undecenoate 2.

the ‘solvent

.,.I 3, .,,:.. ,,:: .,.;,g:..,,,. ~?!,L?. ‘. :I:.. ether ‘(l&,~);~&iyl .\u%Sxetioate the solvent, system .being aceto;,

‘,

(left), undecenyl acrylate (right) and:their synthetic mixture (centre) on direct plate, the solvent system being Alexanc (dry)-ether , (dry)-bromine (95 :5 :I. I, v/v/v).

J.

Clrromatog.,

34 (rgG8)~-543-545

NOTES

545

undecenyl ether and vinyl undecenoate were 42 and 70, respectively. Ally1 undecenoI ate and undecenyl acrylate moved together both on reversed-phase and on argentated ,’ ‘4, thin-layer plates. Since the double bond is in conjugation with the carbonyl group in the acrylic ester and not in the ally1 ester, the procedure of KAUFMANN et aP, of bromination on the plate was examined. Fig. 3 shows that a clear resolution between the ally1 ester and the acrylic ester (23~ x, IOO values, 57 and SS, respectively) could.be obtained on the direct thin-layer plate developed in gz-hexane (dry)-ether (dry) (95 : 5) and containing I:. I ml of bromine per IOO ml solvent. Re,oio9& Research Hyderabad’ (Idia)

Laboratory,

N. G. KULI
J.S. AGGARWAL I N. G. KULICARNI,

N. KRISHNAMURTI, I?. C. CI-IATTERJEE AND J. S. AGGARWAL, J, Am. Oil Chemisls’ Soc., in press. 2 D. SWERN, G.N.BILL,EN AND, I-I. B. KNIGHT,J. Am. Chem.Soc., 6g (1947) 2439. 3 P. C. CHATTERJEE, 1-I; DAKSHINAMURTY AND J. S. AGGARWAL, I?zdiartJ. Teclmol., 4 (1966) 173. 4 0. L. BREICICEAND L.D. I
Received

February

gth, 1968 J. Chvomatog.,

34 (1968)543-545