The present invention provides a novel method for preparing an aminosilane-based compound, by which an aminosilane-based compound used for preparing a modified and conjugated diene-based polymer which shows excellent affinity with an inorganic filler in a rubber composition and increases dispersibility, may be prepared in high purity and high yield.

A method of stabilizing imino-functional silane involving adding thereto at least one Brnsted-Lowry base to inhibit, suppress or prevent the addition reactions of the imino-functional silane with itself to form a imino- and amino-functional silane and the subsequent deamination reactions to form conjugated carbon-carbon double bond-containing imino-functional silanes and stabilized imino-functional silanes containing the at least one Brnsted-Lowry base.

To provide: a purification method which uses a polyimide and/or polyamide imide porous membrane that exhibits excellent removal performance for impurities such as metals, and wherein a liquid that is a silylating agent liquid, a film forming material or a diffusing agent composition is an object to be purified; a purification method for purifying a silicon compound-containing liquid that contains a silicon compound which is capable of producing a silanol group by hydrolysis; a method for producing a silylating agent liquid, a film forming material or a diffusing agent composition, which uses the purification method; a filter medium which is composed of the above-described porous membrane; and a filter device which comprises the above-described porous membrane. A purification method for purifying a liquid, which comprises a step in which some or all of the liquid is caused to permeate through a polyimide and/or polyamide imide porous membrane having communicating pores from one side to the other side by means of differential pressure, and wherein the liquid is a silylating agent liquid, a film forming material or a diffusing agent composition that is used for diffusing a dopant into a semiconductor substrate.

To provide: a purification method which uses a polyimide and/or polyamide imide porous membrane that exhibits excellent removal performance for impurities such as metals, and wherein a liquid that is a silylating agent liquid, a film forming material or a diffusing agent composition is an object to be purified; a purification method for purifying a silicon compound-containing liquid that contains a silicon compound which is capable of producing a silanol group by hydrolysis; a method for producing a silylating agent liquid, a film forming material or a diffusing agent composition, which uses the purification method; a filter medium which is composed of the above-described porous membrane; and a filter device which comprises the above-described porous membrane. A purification method for purifying a liquid, which comprises a step in which some or all of the liquid is caused to permeate through a polyimide and/or polyamide imide porous membrane having communicating pores from one side to the other side by means of differential pressure, and wherein the liquid is a silylating agent liquid, a film forming material or a diffusing agent composition that is used for diffusing a dopant into a semiconductor substrate.

A method of making an organoaminosilane compound, comprising i) combining A) a compound comprising a primary or secondary amine, B) monosilane (SiH.sub.4), and C) a catalyst, where the catalyst comprises magnesium or boron, where A), B) and C) are combined under sufficient conditions to form the organoaminosilane compound and hydrogen. A method of making a silylamine, the method comprising: i) forming an organoaminosilane compound by i) combining A) a compound comprising a primary or secondary amine, B) monosilane (SiH.sub.4), and C) a catalyst, where the catalyst comprises magnesium or boron, and ii) combining ammonia and the organoaminosilane compound produced in i) under sufficient conditions to form a silylamine product and a byproduct, where the byproduct is a primary or secondary amine.

A process for preparing a cyclic polysiloxazane is disclosed. The cyclic siloxazane may optionally be converted to an ?-alkoxy-?-amino-functional polysiloxane. The cyclic siloxazane or the ?-alkoxy-?-amino-functional polysiloxane, may be used as a capping agent for a silanol-functional polyorganosiloxane in a process to make an amino-functional polyorganosiloxane.

A process for preparing a cyclic polysiloxazane is disclosed. The cyclic siloxazane may optionally be converted to an ?-alkoxy-?-amino-functional polysiloxane. The cyclic siloxazane or the ?-alkoxy-?-amino-functional polysiloxane, may be used as a capping agent for a silanol-functional polyorganosiloxane in a process to make an amino-functional polyorganosiloxane.

A method of stabilizing imino-functional silane involving adding thereto at least one Brnsted-Lowry base to inhibit, suppress or prevent the addition reactions of the imino-functional silane with itself to form a imino- and amino-functional silane and the subsequent deamination reactions to form conjugated carbon-carbon double bond-containing imino-functional silanes and stabilized imino-functional silanes containing the at least one Brnsted-Lowry base.

A method of stabilizing imino-functional silane involving adding thereto at least one Brnsted-Lowry base to inhibit, suppress or prevent the addition reactions of the imino-functional silane with itself to form a imino- and amino-functional silane and the subsequent deamination reactions to form conjugated carbon-carbon double bond-containing imino-functional silanes and stabilized imino-functional silanes containing the at least one Brnsted-Lowry base.

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.