Disclosed are (2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-bromo-2,2-difluoroacetate, a waterborne polyurethane, and preparation methods thereof. The (2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-bromo-2,2-difluoroacetate could be used as a modified monomer for preparing a waterborne polyurethane, and substituents at a C2 position of the (2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-bromo-2,2-difluoroacetate are two fluorine atoms and one bromine atom. When it is used for preparing the waterborne polyurethane, fluorine and bromine groups are introduced into the structure of the waterborne polyurethane, and the resultant waterborne polyurethane exhibits good moisture resistance and flame retardance.

SiOC-bonded polyether siloxanes are produced by transesterification of alkoxysiloxanes with polyetherols in the presence of trifluoromethanesulfonate as catalyst. The computational total water content of the reactants including alkoxysiloxanes and polyetherols is ≤5000 ppm by mass, advantageously ≤300 ppm by mass, preferably ≤150 ppm by mass, more preferably ≤100 ppm by mass, in particular ≤50 ppm by mass. The determination of the individual water contents is performed beforehand, preferably by titration according to Karl Fischer.

A method for synthesizing pitavastatin tert-butyl ester includes obtaining a substance B through reacting (4R-CIS)-6-chloromethyl-2,2-dimethyl-1,3-dioxolane-4-acetic acid tert-butyl ester with a substance A under the action of a first base catalyst, 5 oxidizing with an oxidizing agent to obtain a substance C, then reacting with 2-cyclopropyl-4-(4-fluorophenyl)-quinoline-3-formaldehyde under the action of a second base catalyst to obtain a substance D, and finally, carrying out an acid deprotection to obtain pitavastatin t-butyl ester. The reaction conditions of the present invention are mild and controllable, and the reaction conditions of the synthesis of the Julia olefination do 10 not require an ultra-low temperature reaction. The operation is convenient and simple, the stereoselectivity is good, the yield is high, and the synthesized pitavastatin t-butyl ester is a completely non-cis isomer, and its purity is high.

Method for Synthesizing Pitavastatin t-Butyl Ester A method for synthesizing pitavastatin tert-butyl ester includes obtaining a substance B through reacting (4R-CIS)-6-chloromethyl-2,2-dimethyl-1,3-dioxolane-4-acetic acid tert-butyl ester with a substance A under the action of a first base catalyst, 5 oxidizing with an oxidizing agent to obtain a substance C, then reacting with 2-cyclopropyl-4-(4-fluorophenyl)-quinoline-3-formaldehyde under the action of a second base catalyst to obtain a substance D, and finally, carrying out an acid deprotection to obtain pitavastatin t-butyl ester. The reaction conditions of the present invention are mild and controllable, and the reaction conditions of the synthesis of the Julia olefination do 10 not require an ultra-low temperature reaction. The operation is convenient and simple, the stereoselectivity is good, the yield is high, and the synthesized pitavastatin t-butyl ester is a completely non-cis isomer, and its purity is high.

The present invention relates to a method of preparing a heterogeneous linear carbonate, the method including performing a transesterification reaction of dimethyl carbonate (DMC) and ethanol (EtOH) in the presence of a catalyst, wherein the catalyst is one or more selected from the group consisting of lithium methoxide (LME), lithium ethoxide (LEE), sodium methoxide (SME), sodium hydroxide (NaOH), and a mixture thereof, and the catalyst is input in a state of being dissolved in a sulfoxide-based solvent.

Provided herein is a method of preparing a heterogeneous linear carbonate, including: performing a transesterification reaction of dimethyl carbonate (DMC) and ethanol (EtOH) in the presence of a catalyst; and filtering a composite obtained by the transesterification reaction through a filter.

SiOC-bonded polyether siloxanes are produced by transesterification of alkoxysiloxanes with polyetherols in the presence of trifluoromethanesulfonate as catalyst. The computational total water content of the reactants including alkoxysiloxanes and polyetherols is 5000 ppm by mass, advantageously 300 ppm by mass, preferably 150 ppm by mass, more preferably 100 ppm by mass, in particular 50 ppm by mass. The determination of the individual water contents is performed beforehand, preferably by titration according to Karl Fischer.

A process to form a cyclic olefin polymerization catalyst which includes contacting a metal alkoxide with a transition metal halide to form a transition metal precatalyst, and contacting the transition metal precatalyst with a metal alkyl activator to form the activated catalyst comprising a transition metal carbene moiety. A cyclic olefin polymerization process is also disclosed.

A catalyst including: neodymium; sodium; and a ligand, which is a compound expressed by Structural Formula (1) below, wherein the neodymium and the ligand form a complex at a molar ratio of 1:2 (neodymium:ligand): ##STR00001##

This invention relates to nickel catalysts with alkali ions for homopolymerization and copolymerization.