540-97-6Relevant articles and documents
Synthesis of 14C-labeled cyclic and linear siloxanes
Varaprath, Sudarsanan
, p. 37 - 47 (1999)
Simple procedures to synthesize a variety of 14C-labeled monomeric and polymeric siloxanes are described. Specifically, the synthesis of the following siloxanes, some of which are of significant commercial importance are provided: 14C-octamethylcyclotetrasiloxane (D4), 14C-decamethylcyclopentasiloxane (D5), 14C-hexamethyldisiloxane (MM), 14C-dimethyldimethoxysilane and 14C-dimethylsilanediol (DMSD) are examples of discrete monomeric species. 14C-350 and 1000 cSt polydimethylsiloxanes (PDMS) are examples of polymeric species. Synthesis of the monomeric species with the exception of dimethylsilanediol involve reactions of Grignard reagents with the appropriate chlorosilanes, while the polymeric materials were synthesized via acid catalyzed equilibration reaction of 14C-D4 with dodecamethylpentasiloxane (MD3M). The compound 14C-DMSD was obtained by the hydrolysis of 14C-dimethyldimethoxysilane. The labeled materials listed here were synthesized for their utility as tracers in several of the ongoing environmental fate and effects studies as well as toxicological investigations.
Razumovskii et al.
, (1975)
High-efficiency macrocyclic dimethyl siloxane compound preparation method
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Paragraph 0008; 0015, (2017/10/13)
The invention discloses a high-efficiency macrocyclic dimethyl siloxane compound preparation method which comprises the following steps: (1) utilizing tetramethyl disiloxane and octamethyl cyclotetrasiloxane as raw materials, performing ring-openingopen cycle in a sodium hydroxide or potassium hydroxide water solution and then inserting again to obtain dimethyl hydrogen silicone end capped direct-linked siloxane; (2) chlorinating the dimethyl hydrogen silicone end capped direct-linked siloxane with acetyl chloride under a catalytic effect of aluminum trichloride to obtain dimethyl chlorosilane end capped direct-linked siloxane; (3) hydrolyzing the direct-linked siloxane under the alkali condition to obtain varieties of macrocyclic diemthyl silicon ring bodies. The preparation method has simple steps and economical and safe technology and can be used for obtaining varieties of high-purity macrocyclic diemthyl silicon ring body products from simple raw materials; thus, high-difficulty distillation is avoided, and the preparation method is very suitable for industrial production.
Selective Formation of Alkoxychlorosilanes and Organotrialkoxysilane with Four Different Substituents by Intermolecular Exchange Reaction
Komata, Yuma,Yoshikawa, Masashi,Tamura, Yasuhiro,Wada, Hiroaki,Shimojima, Atsushi,Kuroda, Kazuyuki
, p. 3225 - 3233 (2016/11/29)
Alkoxychlorosilanes are scientifically and industrially important toward preparing silicone and silica as well as preparation of siloxane-based nanomaterials by stepwise reactions of Si?OR (R=alkyl) and Si?Cl groups. Intermolecular exchange of alkoxy and chloro groups between alkoxysilanes and chlorosilanes (functional group exchange reaction) provides an efficient and environmentally benign route to alkoxychlorosilanes. BiCl3 as a Lewis acid catalyst can promote the functional group exchange reactions more efficiently than conventional acid catalysts. Higher reactivity has been observed for chlorosilanes with smaller numbers of Si?CH3 groups and for alkoxysilanes with larger numbers of Si?CH3 groups. The reaction mechanism is proposed and selective syntheses of alkoxychlorosilanes are demonstrated. These findings also enable us to synthesize an organotrialkoxysilane with four different substituents.
