The invention relates to a method for purifying halogenated oligosilanes in the form of a pure compound or a mixture of compounds with respectively at least one direct SiSi bond, the substituents thereof being exclusively made from halogen or from halogen and hydrogen and in the composition thereof, the atomic ratio of the substituents:silicon is at least 3:2, by the action of at least one purification agent on the halogenated oligosilane and by isolating the halogenated oligosilanes with improved purity. According to prior art, halogenated monosilanes such as HSiCl.sub.3 are purified by treating with organic compounds, preferably polymers, containing amino groups, and are separated from said mixtures. Based on the contained amino groups, said method can not be used for halogenated oligosilanes as the secondary reactions lead to a decomposition of the products. The novel method is used to provide the desired products in a high yield and purity without using the amino groups.

The invention relates to a process for preparing isocyanate containing alkoxysilane groups, in which, in the sequence of steps A) to D), A) alkoxysilano(cyclo)alkylamine is reacted with dialkyl carbonate in the presence of a basic catalyst to give alkoxysilano(cyclo)alkylurethane, B) simultaneously or successively, the catalyst is deactivated, and low boilers, solids, salt burdens and/or high boilers are removed, C) alkoxysilano(cyclo)alkylurethane obtained after B) is thermally cleaved to release isocyanate containing alkoxysilane groups and by-product, leaving bottoms material, and D) isocyanate containing alkoxysilane groups and by-product are separated from one another and from bottoms material and collected, pa wherein the process regime at least of steps C) to D) is continuous.

The invention relates to a process for preparing isocyanate containing alkoxysilane groups, in which, in the sequence of steps A) to D), A) alkoxysilano(cyclo)alkylamine is reacted with dialkyl carbonate in the presence of a basic catalyst to give alkoxysilano(cyclo)alkylurethane, B) simultaneously or successively, the catalyst is deactivated, and low boilers, solids, salt burdens and/or high boilers are removed, C) alkoxysilano(cyclo)alkylurethane obtained after B) is thermally cleaved to release isocyanate containing alkoxysilane groups and by-product, leaving bottoms material, and D) isocyanate containing alkoxysilane groups and by-product are separated from one another and from bottoms material and collected, pa wherein the process regime at least of steps C) to D) is continuous.

The present invention relates to a process for preparing isocyanate containing alkoxysilane groups, in which, in the sequence of steps A) to D),

A) alkoxysilanoalkylamine is reacted with urea in the presence of an alcohol, optionally in the presence of at least one catalyst, to give alkoxysilanoalkylurethane,

B) simultaneously or successively, if used, the catalyst is removed and/or deactivated, and low boilers, medium boilers and/or high boilers are removed,

C) purified alkoxysilanoalkylurethane is thermally cleaved to release isocyanate containing alkoxysilane groups and by-product, leaving bottoms material, and

D) isocyanate containing alkoxysilane groups and by-product are separated from one another and from bottoms material and collected,

in which, in step C), i) the bottoms material is wholly or partly discharged from the cleavage apparatus, ii) subjected to thermal treatment and/or purification and/or an aftertreatment in the presence of alcohol and iii) the material removed, after thermal treatment and/or purification and/or aftertreatment in step B) or C), is fed in again.

The present invention relates to a process for preparing isocyanate containing alkoxysilane groups, in which, in the sequence of steps A) to D),

A) alkoxysilanoalkylamine is reacted with urea in the presence of an alcohol, optionally in the presence of at least one catalyst, to give alkoxysilanoalkylurethane,

B) simultaneously or successively, if used, the catalyst is removed and/or deactivated, and low boilers, medium boilers and/or high boilers are removed,

C) purified alkoxysilanoalkylurethane is thermally cleaved to release isocyanate containing alkoxysilane groups and by-product, leaving bottoms material, and

D) isocyanate containing alkoxysilane groups and by-product are separated from one another and from bottoms material and collected,

in which, in step C), i) the bottoms material is wholly or partly discharged from the cleavage apparatus, ii) subjected to thermal treatment and/or purification and/or an aftertreatment in the presence of alcohol and iii) the material removed, after thermal treatment and/or purification and/or aftertreatment in step B) or C), is fed in again.

Provided is an ultraviolet ray irradiation device, in which a flow tube through which a substance to be irradiated with ultraviolet ray flows is wound in a spiral manner around a bar-shaped ultraviolet ray source. Also provided is a method for purifying an organic compound that contains an organic lead compound as an impurity, the method comprising: a step for irradiating the organic compound with ultraviolet ray using the ultraviolet ray irradiation device; and a step for removing a lead component that is generated as the result of the irradiation of the organic lead compound with the ultraviolet ray from the organic compound.

Provided is an ultraviolet ray irradiation device, in which a flow tube through which a substance to be irradiated with ultraviolet ray flows is wound in a spiral manner around a bar-shaped ultraviolet ray source. Also provided is a method for purifying an organic compound that contains an organic lead compound as an impurity, the method comprising: a step for irradiating the organic compound with ultraviolet ray using the ultraviolet ray irradiation device; and a step for removing a lead component that is generated as the result of the irradiation of the organic lead compound with the ultraviolet ray from the organic compound.

A reversible photo-switchable isomerization of novel sterically hindered 2,2,6,6-tetraisopropyl-4,4-bis((trimethylsilyl)ethynyl)azobenzene and its synthesis.

A reversible photo-switchable isomerization of novel sterically hindered 2,2,6,6-tetraisopropyl-4,4-bis((trimethylsilyl)ethynyl)azobenzene and its synthesis.

A transesterification process for preparing alkoxysilane includes removal of metal transesterification catalyst from the alkoxysilane transesterification reaction medium.