Preparation of propyl carbonate_industrial additives

Preparation background and overview of propyl carbonate

Organic carbonates such as propyl carbonate are an important class of intermediates in the field of chemistry. They can be used as reagents in methylation reactions and methyl esterification reactions. In these reactions, tetrahydrofuran titanium chloride is used to prepare phenol. Ethers, quats, ureas, urethanes, isocyanates and polycarbonates. These broad applications constitute a large demand for the commercial production of organic carbonates. The industry has put a lot of effort into developing technologies for the production of organic carbonates.

Traditional industrial production is carried out through the phosgenation reaction of methanol. This method is being phased out due to the toxicity of phosgene and the need for corrosion-resistant reactors. Research has developed a catalyst for the synthesis of organic carbonates from urea and hydroxyl-containing compounds. The catalyst includes a calcined product. The calcined product is a hydrated salt containing rare earth elements at a calcining temperature of 150-450°C. Prepared by calcination.

Preparation of propyl carbonate

The preparation of propyl carbonate is divided into the following two steps:

Step 1): Calculate the catalyst precursor La(NO3)3·6H2O in air at a calcination temperature of 350°C for a calcination time of 4 hours. 54.0 g of methanol, 6.0 g of urea and 0.5 g of catalyst prepared as before (ie, 8.3% by weight of urea) were added to the reactor. The reaction was carried out at autogenous pressure (approximately 19.5 atmospheres) and 170°C for 4 hours. During the reaction, the catalyst is prepared by releasing the by-product ammonia through a valve hydroxypyridine located above the reflux column.

Step 2): Add 48.0g propanol, 6.0g urea and 0.8g of the catalyst prepared as before (ie, 13.3% of the weight of urea used) into the reactor. The reaction was carried out for 6 hours at autogenous pressure (approximately 12.2 atmospheres) and 180°C. The yields of dipropyl carbonate (DPC) and propyl carbamate (propyl carbonate, PC) were 54.2% by weight and 18.3% by weight, respectively.