At present, research on the synthesis of itaconic acid from petrochemical products is being carried out at home and abroad, and certain achievements have been made. After three years of research, the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences and Dalian University of Technology have established a new process for the synthesis of itaconic acid from petrochemical products. This technology uses maleic anhydride as the main raw material to obtain itaconic acid through four steps of esterification, addition, methylation and hydrolysis.
Maleic diesters can also be used as starting materials, eliminating the esterification reaction. For example, the use of itaconic acid diester as a product for sale can also save some of these hydrolysis. In this way, the route of the station can be simplified as two key reactions of addition and methylation, and these two reactions can be combined into one step. The route has the following advantages: 1 Rich in raw materials. There are more than 20% maleic anhydride production plants in China with an annual production capacity of about 40,000 tons. After the new maleic anhydride devices such as Tianjin Zhonghe, Liaoning Panjin and Jinxi are put into production, the production capacity will reach 80,000 tons. The maleic anhydride market exceeds supply. , raw materials are adequate. 2 Itaconic acid selectivity is significantly increased. So far, many technical routes reported in the literature that use petrochemical products as raw materials have one common shortcoming, that is, the selectivity is low, only about 30%, and they are at a disadvantage in competition with the fermentation method and are difficult to industrialize. For this reason, the key to the new synthetic route proposed by Dalian Institute of Technology and Dalian University of Technology is to increase the selectivity of itaconic acid. They used the following technical measures: (a) Direct conversion of maleic anhydride to formaldehyde was a two-step reaction. The addition of active hydrogen-containing addition reagent I-IX was first added to the maleic anhydride diester and then to formaldehyde. Methylation reaction. HX is a heteroatom-containing compound and can be converted to a by-product. (b) Homogeneous catalysis with heterogeneous catalysis being highly selective. (c) The gas-solidification reaction is a solid phase reaction in which the liquid phase reaction (d) changes from 300 to 500°C. The high-temperature pressurization reaction is a normal temperature and atmospheric pressure reaction. Since the reaction conditions are mild, side reactions at high temperatures are avoided.
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