Yessenzhanova Nursaule
Caspian University of Technologies and Engineering named after Sh. Yessenov
Aktau, Kazakhstan
Abstract. The use of organic carbon dioxide synthesis is an important form of modern #8220;green chemistry#8221;. The use of carbon dioxide in chemical synthesis is also of great importance in combating the greenhouse effect (the amount of carbon dioxide in greenhouse gases is more than 50%).
The carbon dioxide molecule has a low reactivity, so most of the reactions occurring in it occur only under certain conditions: the use of catalysts and harsh process conditions. In addition, some readily available simple carbon dioxide derivatives are highly active compounds. In particular, syntheses based on alkaline salts of alkyl carboxylic acids are of interest. The latter are easily synthesized by the reaction of carbon dioxide with alcoholates of alkali metals.
Products of phenols carboxylation – hydroxybenzoic acids and its derivatives, have wide using as semiproducts for obtaining pesticides, drugs, photostabizers, dyes and polymeric materials. The most widespread industrial process for manucfacturing of hydroxybenzoic acids and its derivatives is the Kolbe-Shmitt carboxylation of alkali metal phenoxides with carbon dioxide. The serious drawbacks of this process is the need for primary preparation of dry alkali metal phenoxides, which is fraught with great technological difficulties: the removal of water by vacuum distillation and extreme hydroscopycity of dry alkali metal phenoxides. Chemical synthesis in conditions of microwave irradiation in the present time is dynamical developing method of organic synthesis. Using of microwave irradiation in chemical synthesis connect with its ability hasten many chemical reactions. Wide possibility of using MW-irradiation in chemistry provoke big interest of investigation and applied using microwave irradiation. In present work more precisely optimal conditions of phenol carboxylation in conditions of microwave irradiation has been defined. For determination of influence of nature and position of substitutes in phenyl ring on yields of target products the activity a number of methyl- and haloidsubstituted derivatives of phenol has been defined.
Key words: phenol, cresol, chlorophenol, bromophenol, fluorophenol, sodium ethyl carbonate, carboxylation, microwave irradiation, hydroxybenzoic acid, carbon dioxide, salicylic acid.
DOI 10.56525/KQZR1262