Synthesis And The Property Study Of The Polycarboxylic Acids With Sulphur- And Nitrogen-containing Groups.

Polycarboxylic acids chemicals are a type of chemicals containing several carboxyl groups in their moleculars. They are widely studied and showed much application perspective in the fields of spinning and weaving industry, construction, water treatment and coordination chemistry. Recently, membrane separation technology has been adopted extensively to strongly support the development of cycling economics and cleanly producing process. In this work, according to the developing direction of water treatment reagents and membrane separation technology,a summary about the current application situation of water treatment reagents and membrane separation technology has been conducted; Some polycarboxylic acids chemicals with sulphur- and nitrogen-containing groups has been synthesized, which might be used in membrane separation systems.(1)N,N-phosphitemethylene-aspartic acid was synthesized with aspartic acid, formaldehyde and phosohorus trichloride.(2)Dithiocarbanilic ramification of N-phosphitemethylene-aspartic acid was synthesized with aspartic acid, formaldehyde, phosohorus trichloride and carbon bisulphide.(3)N-carboxymethyl-aspartic acid was synthesized with malic acid, methanol, glycine, hydrochloric acid.(4)Dithiocarbanilic ramification of N-carboxymethyl-aspartic acid was synthesized with N-carboxymethyl aspartic acid and sodium pyrosulfite.(5)a) carboxymethylthiosuccinic acid was synthesized with malic acid and mercaptoacetic acid. b) carboxyethylthiosuccinic acid was synthesized with malic acid and 3-mercaptopropanoic acid.The technological conditions in above two synthesis process have been optimized. The above synthesized products were analyzed and characterized with IR,1 HNMR and elemental analysis. The corrosion-scale inhibition property of carboxyethylthiosuccinic acid was evaluated by the static scale inhibition method and polarization curves experiment. Results showed that no evident corrosion-scale inhibition effect of carboxyethylthio- succinic acid existed to calcium carbonate, which could partially be due to that no other active group than carboxyl was contained in it. However the chemical showed some corrosion-scale inhibition effect to red copper when added up to 20mg/L, and carboxyethylthiosuccinic acid appeared cathode Corrosion properties.