Rising crude oil prices and increasing concerns about the environment have led to a sharp increase in global biodiesel production. With the increase of world biodiesel production, the topic of converting glycerol, the main by-product in the biodiesel production process, into a high value-added chemical has become the focus of research at home and abroad. This research team reported for the first time that glycerol efficiently reduces CO in a hydrothermal reaction₂Formed into formic acid and converted into high value-added lactic acid in a yield of nearly 90%. Lactic acid can be further prepared into biodegradable polylactic acid plastics. The project has simple process, convenient operation, and fast reaction speed. It also reduces secondary pollution to the environment caused by waste alkali emissions in the biodiesel production process; it also solves the problem of cheap by-product waste glycerin faced by biodiesel factories, and simultaneously converts waste glycerin into high value-added chemicals, which promotes nature's carbon cycle and has high application value.

Application situation or application prospects：my country's biodiesel production increased by 357% from 2002 to 2007. In 2010, biodiesel production was approximately 200,000 tons. Among them, for every 9 kilograms of biodiesel produced, it is estimated that 1 kilogram of crude glycerol by-product can be obtained. Therefore, in 2010, my country's biodiesel by-product waste glycerin reached 20,000 tons. At the same time, the market potential of polylactic acid plastics is estimated to be 9 billion pounds per year, making it one of the most promising biodegradable plastics. At present, the world's production of lactic acid is 50,000 tons per year; the world demand for lactic acid probably exceeds 60,000 tons. With the increase in lactic acid production, polylactic acid plastics are expected to completely or partially replace polyethylene, polypropylene, polystyrene and other materials in plastic products in the future. This market prospect will be very broad. For example, to completely replace polyethylene, the annual production of lactic acid would require more than 50 million tons. Moreover, with the rapid development of China's economy, the demand for lactic acid will continue to increase significantly. Therefore, the conversion of waste glycerol, a by-product of the biological industry, into lactic acid has broad application prospects.

CO₂It is the greenhouse gas with the greatest impact on global climate change, so research is needed to quickly and effectively reduce CO.₂Technology for organic resources has important practical significance. On the other hand, waste glycerin is the main by-product of biodiesel. With the development of the biodiesel industry, its main by-product is cheap and has become a problem faced by biodiesel companies. This project uses environmentally friendly hydrothermal technology, uses waste glycerol or isopropanol as a reducing agent, and utilizes the characteristics of high temperature and high pressure water to convert CO without catalysis₂It is converted into formic acid and waste glycerol is converted into lactic acid.