The present invention discloses a synthesis method of lactide by confinement effect catalysis of crystalline porous polymer material, wherein the method comprising: (I) synthesis of catalyst; (II) synthesis of lactide by confinement effect catalysis; and (III) purification of lactide. In the present invention, a yield of L-lactide by catalysis of L-lactic acid by crystalline polymers is as high as 85.6%, which is 10% higher than the yield of lactide by H-? molecular sieve reported in documents currently available; it is easy to prepare the crystalline porous polymer material catalyst, which is environmental friendly, has a high yield and is recyclable, for consecutive 7 times the catalysis yield is maintained to be higher than 70%, and catalysis yield conservation rate is far higher than catalysis effects of catalysts reported in documents currently available.

The present invention describes a process to prepare catalyst systems based on metal salts, supported on natural polymers and co-catalyzed by organic bases, for the catalytic transformation of carbon dioxide to organic carbonates through cycloaddition reactions to epoxides. The advantages of the presented system can be summarized on the use of raw materials of low cost for the preparation of the catalyst system, minimal environmental risk due to the low toxicity of the materials used, in some cases biodegradable such as the natural polymers, as well as high catalytic efficiency, reaching selectivities up to 100% and in some cases quantitative yields.

Methods are provided for modifying hydrogenation catalysts having silica supports (or other non-alumina supports) with additional alumina, and using such catalysts to achieve unexpectedly superior hydrogenation of feedstocks. The modified hydrogenation catalysts can have a relatively low cracking activity while providing an increased activity for hydrogenation.

Methods are provided for modifying hydrogenation catalysts having silica supports (or other non-alumina supports) with additional alumina, and using such catalysts to achieve unexpectedly superior hydrogenation of feedstocks. The modified hydrogenation catalysts can have a relatively low cracking activity while providing an increased activity for hydrogenation.

Methods are provided for modifying hydrogenation catalysts having silica supports (or other non-alumina supports) with additional alumina, and using such catalysts to achieve unexpectedly superior hydrogenation of feedstocks. The modified hydrogenation catalysts can have a relatively low cracking activity while providing an increased activity for hydrogenation.

The present invention discloses processes for producing -dicarbonyl compounds by contacting an aldehyde compound, an ,-unsaturated carbonyl compound, and a catalyst composition in the presence of an amide diluent. The resultant -dicarbonyl compounds then can be used to synthesize pyrrole compounds, such as 2,5-dimethylpyrrole.

Provided is a polymerization catalyst including a metal complex obtained by mixing at least one ketimine derivative selected from the group consisting of a -ketimine compound and a tautomer thereof with a compound having at least one metal selected from among Group 4 and 5 transitional metals, an organoaluminum compound, and a halogen compound.

Methods are provided for modifying hydrogenation catalysts having silica supports (or other non-alumina supports) with additional alumina, and using such catalysts to achieve unexpectedly superior hydrogenation of feedstocks. The modified hydrogenation catalysts can have a relatively low cracking activity while providing an increased activity for hydrogenation.

The present invention relates to a hybrid nanostructured photocatalyst, comprising a first nanoparticle comprising silver halide (AgX); a second nanoparticle, which is formed on an outer surface of the first nanoparticle and comprises Ag; and a polymer formed on any one outer surface of the first nanoparticle and the second nanoparticle, and a preparation method thereof. Specifically, the present invention provides a hybrid nanostructured photocatalyst having a high photocatalytic activity in a visible light region and a preparation method thereof.

The present invention relates to a process for the preparation of an optically pure (+) or (?) enantiomer of an iminium salt having the formula (I), aid process comprising the following steps: a) a reduction step of an iminium salt having the formula (II), said salt being in the form of a racemic mixture, in order to obtain a compound having the formula (III) in the form of a racemic mixture, b) a step of chiral HPLC separation of the compound of formula (III) in the form of a racemic mixture, for obtaining an optically pure (+) or (?) enantiomer compound having the formula (IV), and c) an oxidation step of the compound of formula (IV) for obtaining the compound of formula (I).