The present invention provides a catalyst for synthesizing a cyclic carbonate and a preparation method and use thereof. A diamine compound X, a salicylaldehyde-containing compound and a metal source M are subjected to reaction, and then added with a phenothiazine compound Y for continuous reaction to obtain a phenothiazine metal Schiff base catalyst. The formation of phenothiazine free radicals by phenothiazine compounds with a central metal can protect the central metal in the course of reaction and inhibit inactivation caused by the self-polymerization of the central meta, thus improving the activity and stability of a catalyst. Phenothiazine compounds can be present as a polymerization inhibitor to inhibit the generation of by-products such as polycarbonates and polyethylene glycol and enhance the selectivity of the catalyst during the reaction. The phenothiazine compounds are alkaline and can adsorb and activate carbon dioxide during reaction, which helps to improve the reaction efficiency. The phenothiazine metal Schiff base catalyst prepared in the present invention has high activity, strong stability and good selectivity and thus, can achieve the efficient catalyzed synthesis of cyclic carbonates under mild conditions.

A production method of producing a fluorine-containing olefin by allowing a first olefin represented by the following Formula (1) and a second olefin to react with each other in the presence of a ruthenium compound represented by the following Formula (X) is provided. ##STR00001##

Provided is a chelate complex comprising (a) a rare earth metal cation M; (b) a chelate ligand of formula (CL1 A) or (CL1 B) c) at least one anionic nucleophilic ligand LN which is coordinated as a further ligand to the rare earth metal cation; and d) optionally one or more neutral donor ligands LD coordinated as ligands to the rare earth metal cation. Moreover, provided are a process for the preparation of a chelate complex, a process for the preparation of a polymer comprising a polymerization reaction of chiral cyclic ester monomers, and a poly(3-hydroxy butyrate) polymer which can be provided by the process.

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