Yunzheng Li

A novel polyaspartic acid derivative with multifunctional groups for scale inhibition application

ABSTRACT Polyaspartic acid is a green biodegradable antiscalant and widely applied in water treatment field. However, its scale inhibition efficiency is not prominent, especially for calcium orthophosphate. So we introduced acylamino and hydroxyl groups simultaneously to prepare a novel polyaspartic-acid derivative (PASPTU) with multifunctional groups by the reaction of polysuccinimide with threonine and urea. The graft copolymer was analyzed by using nuclear magnetic resonance, gel permeation chromatography, thermogravimetric analyzer and Fourier transform infrared spectroscopy. Its scale inhibition performance for calcium orthophosphate, calcium sulfate and calcium carbonate was evaluated. The findings showed that the scale inhibition rates of the graft copolymer reached up to 100% for calcium orthophosphate, 100% for calcium sulfate and 91% for calcium carbonate at certain dosages. The findings above showed that the copolymer had excellent scale inhibition efficiency for calcium salts in water treatment processes.

4,5,6-Tri-O-acetyl-2,3-di-S-ethyl-2,3-dithio-d-allose diethyl dithio­acetal

The title compound, C20H36O6S4, was obtained by ethanethiolysis of 3,5,6-tri-O-acetyl-1,2-O-isopropylidene-α-d-glucofuranose. One of the ethyl groups is disordered over two sites with refined occupancies of 0.869 (6) and 0.131 (6). Compared with the precursor, the absolute configuration of the stereocenters at positions C-3 and C-2 are inverted and maintained, respectively.

(5S*,6R*,7R*)-6-Formyl-5-phenyl-7-propyl-perhydro-pyrazolo[1,2-a]pyrazol-1-one.

The title compound, C16H20N2O2, was obtained by catalytic asymmetric cycloaddition of trans-3-propylacrolein with 1-benzylidenepyrazolid-3-one betaine. There are two symmetry-independent molecules in the asymmetric unit. In both molecules, the two five-membered heterocyclic rings adopt envelope conformations.