Synthesis of silanes with more than three silicon atoms are disclosed (i.e., Si.sub.nH.sub.(2n+2) with n=4-100). More particularly, the disclosed synthesis methods tune and optimize the isomer ratio by selection of process parameters such as temperature, residence time, and the relative amount of starting compounds, as well as selection of proper catalyst. The disclosed synthesis methods allow facile preparation of silanes containing more than three silicon atoms and particularly, the silanes containing preferably one major isomer. The pure isomers and isomer enriched mixtures are prepared by catalytic transformation of silane (SiH.sub.4), disilane (Si.sub.2H.sub.6), trisilane (Si.sub.3H.sub.8), and mixtures thereof.

A method of forming dialkyl carbonate is provided, which includes introducing carbon dioxide into a catalyst to form dialkyl carbonate, wherein the catalyst is formed by activating a catalyst precursor using alcohol, wherein alcohol is R.sup.3—OH, and R.sup.3 is C.sub.1-12 alkyl group or C.sub.5-12 aryl or heteroaryl group. The catalyst precursor is formed by reacting Sn(R.sub.1).sub.2(L).sub.2 and Ti(OR.sup.2).sub.4, and Sn(R.sup.1).sub.2(L).sub.2 and Ti(OR.sup.2).sub.4 have a molar ratio of 1:2 to 2:1. R.sup.1 is C.sub.1-10 alkyl group, R.sup.2 is H or C.sub.1-12 alkyl group, and L is O—(C═O)—R.sup.5, and R.sup.5 is C.sub.1-12 alkyl group. The dialkyl carbonate is ##STR00001##

A system and method of producing carbon nanotubes from flare gas and other gaseous carbon-containing sources.

The invention relates to the field of oligomerization of olefins to produce linear α-olefins, in particular hexene-1, with the use of a catalyst system. The catalyst system comprises a chromium source compound, a nitrogen-containing ligand, alkylaluminum, and a zinc compound, wherein catalyst system is activated during its preparation by 1) heating some and SHF irradiation (microwave irradiation) of alkylaluminum or a mixture of the alkylaluminum and the zinc compound, or by 2) heating alkylaluminum or a mixture of the alkylaluminum and the zinc compound, followed by holding (aging) the prepared catalyst system for a certain period of time.

The present disclosure provides a method and a catalyst for selective oligomerization of ethylene. The raw material for the catalyst consists of a dehydropyridine annulene-type ligand, a transition metal compound, and an organometallic compound in a molar ratio of 1:0.5-100:0.1-5000. The present disclosure also provides a method for selective oligomerization of ethylene accomplished by using the above-mentioned catalyst. The catalyst for selective oligomerization of ethylene has high catalytic activity, high selectivity for the target products 1-hexene and 1-octene, and low selectivity for 1-butene and 1-C.sub.10.sup.+.

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.

Disclosed are a catalyst system capable of selectively oligomerizing olefins including ethylene and a method for preparing an olefin oligomer by using the same and, specifically, a novel catalyst system capable of trimerizing and tetramerizing olefins, unlike olefin oligomerization catalyst systems that have been reported so far, and a method for preparing an olefin oligomer by using the same. The present invention provides a catalyst system for olefin oligomerization, the catalyst system comprising: a ligand compound represented by chemical formula 1; a chromium compound; a metal alkyl compound; and an aliphatic or alicyclic hydrocarbon solvent.

The invention relates to a new dialkyl tin oxide catalyst composition and its use for the synthesis of amino alkyl (meth)acrylates by transesterification from an alkyl (meth)acrylates and an amino alcohol, and especially 2-dimethylaminoethyl (meth)acrylate.

The invention also relates to polymers made with quaternized amino alkyl (meth)acrylates and use of said polymers in water treatment, sludge dewatering, papermaking process, agriculture, cosmetic and detergency composition, textile process, oil and gas recovery process such as enhanced oil recovery, fracturing, mining operation such as tailings treatment.

The present invention relates to a process for preparing the Alectinib or a pharmaceutically acceptable salt thereof using lesser reaction steps and also eliminating expensive and time-consuming column chromatography. The invention also relates to novel polymorphic forms of Alectinib and Alectinib hydrochloride.

The present invention relates to the use of n-butyllithium for catalyzing the hydroboration of an imine and a borane. A catalyst, the borane and the imine are sequentially stirred and mixed uniformly, and are reacted for 1-2 h; the mixture is exposed to air to terminate the reaction; and the reaction liquid is subjected to reduced pressure to remove the solvent, so as to obtain a borate with different substituents. The n-butyllithium disclosed in the present invention can be used for catalyzing the hydroboration of the imine and the borane in high activity under room temperature conditions, the amount of the catalyst is only 4-5 mol % of the molar weight of the imine, and the yield of the reaction can reach 90% or more.