New Technology On Preparing Acrylic Acid From Bio-Lactic Acid

Acrylic acid and its ester derivatives are principal raw materials in the manufacture of polymeric products. The demand of acrylic acid all over the world is increasing rapidly. In order to exploit and utilize the biological resources better, to look for substitutes for the petrochemicals. The highest total yield of methyl acrylate and acrylic acid is60.1%with a feed stock with a mass ratio of water/methyl lactate40/60, which is pumped into the catalyst bed at400℃, previously evaporated at235℃, a flow of N215mL·min-1,1.5ml·h-1feed stock. The catalysts are calcined at430℃. The optimum reaction temperature for neodymium phosphate catalyst is325℃, at which the total yield of methyl acrylate and acrylic acid30.4%is achieved, and38%for13X zeolite at300℃. The modifications to zeolites are also investigated. The selectivity of the methyl acrylate and acrylic acid is more than80%with the second-stage reaction, which can utilize both the13X zeolite and the sulphates catalyst.O-acetyl-ethyl lactate is produced by reaction of ethyl lactate and acetic anhydride (1:1.5), at60℃for6hr, with DMAP as catalyst and sodium carbonate as pacing antacids. O-acetyl-ethyl lactate is extracted from the organic layer. The product obtained from first step reaction is diluted by the same amount of ethanol. The solution is the feed stock for the second step reaction. The highest yield of acrylic acid and ethyl acrylate is achieved at310℃reaction temperature, with0.02mL·min-1sampling rate evaporated at230℃, with1.5g13X zeolite as catalyst.