Russian Journal of Applied Chemistry, Vol. 74, No. 2, 2001, p. 350. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 2, 2001, pp. 342 3343. Original Russian Text Copyright C 2001 by Osadchenko, Tomilov. BRIEF ˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝ ˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝˝ COMMUNICATIONS I. M. Osadchenko and A. P. Tomilov State Research Institute of Organic Chemistry and Technology, Moscow, Russia Received June 23, 2000 Abstract-The feasibility of p-cresol alkylation with isohexyl alcohol, using phosphotungstic heteropoly acid as catalyst, was examined. Alkyl derivatives of p-cresol find application as The experiment with phosphomolybdic acid H PMo O failed, because the catalyst appeared antioxidants, surfactants, and perfumes. In particular, 7 12 42 to be reactive toward the starting compounds. products of p-cresol alkylation with isohexyl alcohol are used in synthesis of vetinone perfume (see scheme). Below is given a typical procedure for condensa- tion of p-cresol with isohexyl alcohol. OH A reactor equipped with a reflux condenser with +(CH ) CH 3C(CH ) 6 a Dean3Stark trap, a stirrer, a thermometer, and a drop- 3 2 3 2 ping funnel was charged with 102 g (0.982 mol) of OH p-cresol and 2.0 g of H PW O . The mixture was CH 3 7 12 42 heated on an oil bath to 85395oC, and 51 g (0.50 mol) OH OH O of isohexyl alcohol was added dropwise at this tem- g g g g R R R perature over a period of 40 min. The temperature was j j j j H O 2 2 76 76 gradually raised to 1053120oC, and the mixture was re- 3H O 2 88 fluxed for 4 h 40 min. In the process, water was sepa- g g g rated in the Dean3Stark trap. After the reaction was CH CH CH 3 3 3 complete, the content of the target product was de- termined by GLC to be 50.5%. To isolate the product, where R = (CH ) C 3CH(CH ) . 3 2 3 2 the mixture was neutralized with 3 g of sodium carbon- Kheifits et al. [1, 2] studied the alkylation of ate. The neutralized mixture was vacuum-distilled. p-cresol in the presence of various catalysts including The target fraction (bp 125 3140oC/8310 mm Hg) con- Fe (SO ) , ZnCl ,BF , and H SO . Sulfuric acid ap- 2 4 3 2 3 2 4 tained, according to GLC, 97% 4-methyl-2-isohexyl- peared to be the most suitable. At a 2 : 1 molar ratio phenol. The product yield was 53 g (55.2% in terms of of p-cresol to alcohol and a temperature of 110 3 loaded isohexyl alcohol), and the amount of bottoms, 120oC, the target product was obtained in about 50% 7.2 wt % relative to the target fraction (with sulfuric yield. A major drawback of the process is the ap- acid as catalyst, the amount of bottoms was 15 wt %). preciable tarring of the reaction mixture containing The alkylation of p-cresol with 2-methyl-2-pentan- about 15 wt % tar. ol was performed similarly. The yield of the condensa- tion product, 4-methyl-2-(2-methyl-2-pentyl)phenol, The tarring, and also the high corrosive activity was 50%. of sulfuric acid stimulated us to look for new cata- lysts for this process. We decided to test heteropoly REFERENCES acids which have recently found use as catalysts in many processes . Among the tested heteropoly 1. Kheifits, L.A. and Podberezina, A.S., in Problemy or- ganicheskogo sinteza (Problems of Organic Synthesis), acids, the best results were obtained with reagent- Moscow: Nauka, 1965, pp. 124 3132. grade phosphotungstic acid H PW O [TU (Techni- 7 12 42 2. Kheifits, L.A., Podberezina, A.S., Klimakhina, S.T., cal Specifications) 6-09-4376 378]. With this catalyst, and Grigor’eva, L.T., Maslozhir. Prom 3st., 1976, no. 7, the formation of tars under the conditions recom- pp. 32334. mended for the process with sulfuric acid decreased 3. Kozhevnikov, I.V., Usp. Khim., 1987, vol. 56, no. 9, by more than a factor of 2. pp. 141731442. 1070-4272/01/7402-0350 $25.00 C 2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry – Springer Journals
Published: Oct 13, 2004
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