SYNTHESIS AND PROPERTIES OF THE METHYL ESTERS OF 3,5-DI-METHYLCYCLOALKYL-4-HYDROXYPHENYLPROPIONIC ACID

A study was carried out and a method was developed for the synthesis of sterically hindered phenols by cycloalkylation of methyl ester of 4-hydroxyphenylpropionic acid with 1-methylcyclopentene, 1- and 3-methylcyclohexene in the presence of a KU-23 catalyst (modification 10/60 (GOST 20298)) with a pore radius of 250-600 Å. The optimal conditions for cycloalkylation of methyl ester of 4-hydroxyphenylpropionic acid with methylcyclenes in the presence of a KU-23 catalyst (temperature 100-110 ºС, reaction time 5-6 h, molar ratio of ether to cyclene 1:2, amount of catalyst 10% per taken ester) were determined. At these conditions, the highest values of yields and selectivity of the target product are achieved. The yields of the target products were 69.8-72.5% of the theory for the taken ester and the selectivity was 89.6-94.3% for the target product. The chemical structures of the synthesized methyl esters of 3,5-di-cycloalkyl-4-hydroxyphenylpropionic acid were confirmed by spectral methods of analysis, the purity and fractional composition – by chromatographic methods of analysis. For the compounds the physicochemical parameters, molecular weight were determined and elemental analysis was carried out. For the processes of catalytic cycloalkylation of methyl ester of 4-hydroxyphenylpropionic acid with methylcyclenes the material balance was calculated and compiled. The synthesized methyl esters of 3,5-dicycloalkyl-4-hydroxyphenylpropionic acid were tested as stabilizers for the polyurethane polymer. Esters were added during the synthesis of a polyurethane polymer. Then the membrane were prepared from a mixture of polymer and ester. These membranes were subjected to light and heat aging at a temperature of 150 °C for 6 h, UV irradiation for 40 h. Based on the tests carried out, it was found that methyl ester of 3,5-di-(1-methylcyclohexyl)-4-hydroxyphenylpropionic acid can be recommended for use as a heat stabilizer for polyurethane polymer and face coverings for artificial leather based on it. For citation: Naghiyeva M.V., Rasulov Ch.K. Synthesis and properties of the methyl esters of 3,5-dimethylcycloalkyl-4-hydroxyphenylpropionic acid. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 6. P. 85-93. DOI: 10.6060/ivkkt.20236606.6777.