Oxalyl Chloride CAS 79-37-8

The German patent introduces that oxalic acid and phosphorus pentachloride react in phosphorus oxychloride in the presence of triethylamine to obtain oxalyl chloride, and the yield can reach 73%.

Domestic production example: in a 2L four-necked flask with a stirrer, a solid raw material supply funnel and a distillation device, 1kg of phosphorus pentachloride and 12g of triethylamine are suspended in 500g of phosphorus oxychloride, and at a reaction temperature of 60° C. and Under the pressure of 2.5kPa, 100g of water-free oxalic acid was supplied for 40min, and finally stirred at 70°C and 2.5kpa for 30min. During the supply and stirring, in the distillation apparatus, we obtained: w=20.7% oxalyl chloride and w=78.4% trichloride Phosphorus oxide mixture 4979, unreacted phosphorus pentachloride 589 and added triethylamine and residual phosphorus oxychloride in the reactor. In terms of oxalic acid, the yield is 73%; in phosphorus pentachloride, the yield is 80%.

The Japanese patent describes the chlorination of oxalate esters (dimethyl, diethyl, dipropyl or diphenyl) to form chlorine oxalate in the presence of light. For example: 12g of dimethyl oxalate is injected with chlorine gas at 160°C at a rate of 50cm3/min under the illumination of light, and the reaction is carried out for 8h to obtain 10.2g of oxalyl chloride. 17.5g of dipropyl oxalate can be reacted with light at 165℃ for 8h to obtain 8.9g of oxalyl chloride.

The European patent has introduced that oxalyl chloride is obtained through three-step chlorination reaction: 1. trichloroacetyl chloride and ethylene glycol react without solvent to obtain ethylene glycol bis-trichloroacetyl ester; 2. above-mentioned substances are subjected to photochlorination to obtain four Chlorinated ethylene glycol bis-trichloroacetate; ③ This substance is rearranged at 50-160 ° C to obtain oxalyl chloride.

The US patent describes the decomposition of tetrachloroethylene carbonate in the presence of 1% dimethylformamide at 80-85 °C to obtain 79% oxalyl chloride and 21% phosgene.

The Japanese patent describes that tetrachloroglycolide or its polymer is decomposed in the presence of Lewis base to obtain oxalyl chloride. For example: a mixture of 2.99g of tetrachloroglycolide and 0.1g of triethylamine is heated to 64.5-74°C in a chlorinated benzene solvent, kept for 0.5h, and then distilled to obtain oxalyl chloride. Its yield was 89.3% (purity 96.3%).