2370-88-9Relevant academic research and scientific papers
Hydrocarbyl the cyclosiloxane preparation method (by machine translation)
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Paragraph 0019; 0026; 0027; 0031, (2017/09/20)
The invention discloses a preparation method of alkyl cyclosiloxane. The preparation method is characterized by comprising the following steps: taking alkyl halogenosilane as a raw material, taking crown ether as a solvent and dropping the alkyl halogenosilane in a mixed solution formed by water and the crown ether while continuously stirring the alkyl halogenosilane; carrying out hydrolysis at a certain temperature to carry out condensation polymerization; standing after the reaction to carry out layering; and directly carrying out decompressed rectification on the obtained hydrolyzed oil to separate trialkylcyclotrisiloxane, tetraalkylcyclotetrasiloxane, pentaalkylcyclopentasiloxane and hexaalkylcyclohexasiloxane. The preparation method has the advantages that alcohols and low-boiling point hydrocarbons are not used as solvents, the crown ether is used as solvent and direct rectification is carried out on the prepared hydrolyzed oil to obtain the alkyl cyclosiloxane, so that the processes of washing, neutralization, drying and filtering are saved; and the solvent which undergoes standing and layering after the hydrolysis can be reused or can be cooled to a certain temperature to separate out the crown ether for recovery, so that the production cost is saved.
Preparation of cyclic oligosiloxane
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Page/Page column 9, (2008/06/13)
Cyclic oligosiloxane is prepared through disproportionation reaction of organopolysiloxane in the presence of a catalyst. Cyclic oligpsiloxane of high purity can be produced in high yields by using a catalyst having formula (4): wherein M is Al, Ti, Zr, Sn or Zn, p is the valence of M, and R4 is a monovalent hydrocarbon group or the like.
PROCESS FOR PREPARING CYCLIC ORGANOHYDROGENSILOXANES
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Page/Page column 6; 7, (2008/06/13)
A process for preparing cyclic organohydrogensiloxanes comprises: (A) contacting a silane of the formula RHSiCl2, where R is selected from alkyl radicals having 1 to 12 carbon atoms and aryl radicals, with water to form a hydrolyzate comprising cyclic organohydrogensiloxanes and linear organohydrogensiloxanes, and (B) contacting the hydrolyzate with an acidic rearrangement catalyst in the presence of an inert liquid diluent to increase the ratio of the cyclic organohydrogensiloxanes to linear organohydrogensiloxanes in the hydrolyzate. The acidic rearrangement catalyst is an organic compound containing a strong acid group, for example a sulphonic acid, which is dissolved in the inert diluent present.
FEATURES OF INFLUENCE OF HCl ON HYDROLYTIC COPOLYCONDENSATION OF BIFUNCTIONAL ORGANOCHLOROSILANES WITH TRIMETHYLCHLOROSILANE
Kopylov, V. M.,Agashkov, S. P.,Sunkovich, G. V.,Prikhod'ko, P. L.
, p. 1257 - 1261 (2007/10/02)
The hydrogen chloride that is formed in the hydrolytic copolycondensation of R'RSiCl2 with Me3SiCl affects the composition of the reaction products only at cocentrations above 30-35percent, where it is responsible for splitting out the terminal trimethylsiloxy group.The stability of the terminal groups increases with increasing size of the substituents on the silicon atom in the R'RSiCl2.The total yield of Me3SiO(R'RSiO)mSiMe3 with m = 1-4 also increases with increasing size of the substituents on the silicon atom in the R'RSiCl2.The total yield of p with p = 3-5 increases with decreasing tendency of the R'RSiCl2 to form rings by hydrolytic polycondensation, and with increasing sensitivity of the terminal trimethylsiloxy group in the cocondensation products to the action of HCl and its activity with respect to the siloxane bond.
