Greener Production Process of Acetylene and Calcium Diglyceroxide via Mechanochemical Reaction of CaC2 and Glycerol

Calcium carbide (CaC2) is widely used for the production of various acetylene derivatives, accompanying with a huge amount of carbide slag waste. To develop a clean production process, we explored the reaction of CaC2 and glycerol at varying conditions for the first time. The products were characterized by various techniques. It is observed that CaC2 can react with glycerol at ambient temperature in a stirred mill, with 96% of glycerol conversion after 1 h of milling at rotating speed of 450 rpm. Meanwhile, a quantitative amount of anhydrous acetylene free of PH3, AsH3, and H2S was obtained directly due to the lower reactivity of glycerol that suppresses its side reactions with the concomitant Ca3P2, Ca3As2, and CaS impurities. The mechanochemical reaction of CaC2 with glycerol is more efficient than the corresponding thermochemical reaction at high temperature, and CaC2 shows much higher reactivity than CaO with glycerol. The present process achieves direct production of high purity acetylene along with efficient conversion of glycerol to calcium diglyceroxide, a green plasticizer and thermal stabilizer of plastics, realizing high value utilization of both glycerol and CaC2 with full atom economy. This process may aid the sustainable development of the downstream industry of calcium carbide.