In general, glycerol conversion include chemical method and biological method, the vast majority is given priority to with chemical catalytic conversion, catalytic products, according to a report in the literature can be divided into two kinds, one is only the substrate glycerol, under different methods into the like – propylene glycol, propylene glycol, 1, 2, 1, 3 – propanediol), ethylene glycol, dihydroxyacetone, and syngas production; The other is the combination of glycerol with other reagents, such as cycloxylothane, which is produced by hydrogen chloride, and ester products, which are produced by esterification with carboxylic acid.
Propylene glycol (propylene glycol) including 1, 2 – propylene glycol, 1, 3 – propanediol two products.1, 2-propanediol (PG) is mainly used in the production of coatings and unsaturated polyester resin (UPR). In addition, it can be used as an antifreeze agent instead of glycol for antifreeze aircraft and as a coolant in food. In addition, a large amount of propylene glycol is used in the production of plasticizer and hydraulic brake fluid, it can also be used in non-ionic detergents and as a moisturizer in medicine, cosmetics, animal food, the tobacco industry. Propylene glycol is also a good solvent, can be used in ink and epoxy resin.1, 3 – propanediol (PDO) is a kind of important organic chemical raw materials, its application field is similar to other glycols, can be directly used in antifreeze, a variety of plasticizers, synthetic detergent, antiseptic, and emulsifier raw material, it is also used in synthesis of medicine and used as intermediates in organic synthesis, but it is the main application field is used to make a new polyester poly (2-1, 3 – propanediol terephthalate (PTT) materials. According to incomplete statistics, at present, the total output of the global PG market reaches 1.75m t/ year. The largest producer of PG is dow 56.15 million t/ year, accounting for about 1/3 of the total production, followed by Lyondell with 24%. Propylene glycol producers are mainly concentrated in North America with an annual output of 610,000 tons, followed by Europe with an annual output of 540,000 tons. According to statistics, the apparent consumption of propylene glycol in China is about 12 million tons per year. Due to the slow growth of domestic propylene glycol demand, it is estimated that the apparent consumption will increase less in the next few years, and domestic PG production is in surplus. In addition, in the current consumption structure of propylene oxide, the consumption ratio of the propylene glycol industry is only 7.7%, far lower than the global average. After 2008, the production of propylene glycol in China will increase rapidly, and the proportion of propylene glycol will increase greatly. It is estimated that the total consumption of propylene glycol industry will reach 112,000 tons by 2010, accounting for more than 10% of the total consumption of propylene oxide. Therefore, PG needs to reduce the cost technically and pull the demand. As a monomer synthesized polyester material,1, 3-propanediol shows better performance and stability than the monomer synthesized polyester material such as glycol, butanediol and 1, 2-propanediol. In the next few years, the PTT scale will reach an annual output of millions of tons, thus the demand for 1, 3-pd will increase greatly. In 2010, the global demand for PTT will exceed 1000kt, and the market prospect is good. However, the production capacity of 1, 3-propanediol in China is insufficient, so it is particularly important to develop the technology of large-scale production of 1, 3-propanediol like glycerin.