GB843273A - Improvements in the preparation of cyclic dimethylsiloxanes - Google Patents

Improvements in the preparation of cyclic dimethylsiloxanes

Info

Publication number
GB843273A
GB843273A GB17823/57A GB1782357A GB843273A GB 843273 A GB843273 A GB 843273A GB 17823/57 A GB17823/57 A GB 17823/57A GB 1782357 A GB1782357 A GB 1782357A GB 843273 A GB843273 A GB 843273A
Authority
GB
United Kingdom
Prior art keywords
siloxane
parts
cyclic
groups
impure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB17823/57A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Union Carbide Corp
Original Assignee
Union Carbide Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Union Carbide Corp filed Critical Union Carbide Corp
Publication of GB843273A publication Critical patent/GB843273A/en
Expired legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07FACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/02Silicon compounds
    • C07F7/08Compounds having one or more C—Si linkages
    • C07F7/20Purification, separation
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07FACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/02Silicon compounds
    • C07F7/08Compounds having one or more C—Si linkages
    • C07F7/0834Compounds having one or more O-Si linkage
    • C07F7/0838Compounds with one or more Si-O-Si sequences
    • C07F7/0872Preparation and treatment thereof
    • C07F7/0874Reactions involving a bond of the Si-O-Si linkage
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07FACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/02Silicon compounds
    • C07F7/21Cyclic compounds having at least one ring containing silicon, but no carbon in the ring
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Silicon Polymers (AREA)

Abstract

Cyclic dimethylsiloxanes having from 3 to 7 siloxane units in the molecule are prepared from dimethyl-siloxanes which contain trimethyl-and monomethyl-siloxane groups by heating the impure dimethyl-siloxane at a temperature between 80 DEG and 200 DEG C. in the presence of metallic potassium or an acid or alkaline catalyst and an inert organic liquid which is at least a partial solvent for the impure siloxane. The cyclic compounds are separated from the mixture by distillation. The impure siloxanes contain at least 85 parts by weight of dimethylsiloxane groups and up to 15 parts of combined monoand trimethyl siloxane groups. If the former groups are present in amounts less than 85%, the process must be repeated. The starting materials may be linear, cyclic or cross-linked dimethyl siloxanes, including elastomers which contain fillers. Suitable organic liquids are hydrocarbons and ethers, e.g. diphenyl ether, diisopropyl ether, octadecane, deca- and tetra-hydronaphthalene, biphenyl, terphenyl, ditolylethane, and a mixture of hydrogenated derivatives of terphenyl. The pressure may be varied depending on the boiling point of the liquid. From 5 to 90 parts by weight of the solvent per 100 parts of total weight of solvent and siloxane are generally used. Suitable catalysts, in addition to metallic potassium, are sulphuric acid, alkali metal hydroxides, oxides, carbonates and bicarbonates, tetralkylammonium hydroxides and potassium organosilanolates. Examples are given, and the preparation is also described of an elastomer from a gum derived from the pure cyclic tetramer, ethylsiloxane-coated silica filler and benzoyl peroxide. Reference has been directed by the Comptroller to Specification 799,917.
GB17823/57A 1956-06-06 1957-06-05 Improvements in the preparation of cyclic dimethylsiloxanes Expired GB843273A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US843273XA 1956-06-06 1956-06-06

Publications (1)

Publication Number Publication Date
GB843273A true GB843273A (en) 1960-08-04

Family

ID=22184252

Family Applications (1)

Application Number Title Priority Date Filing Date
GB17823/57A Expired GB843273A (en) 1956-06-06 1957-06-05 Improvements in the preparation of cyclic dimethylsiloxanes

Country Status (4)

Country Link
BE (1) BE558079A (en)
DE (1) DE1083820B (en)
FR (1) FR1176541A (en)
GB (1) GB843273A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2908249A1 (en) * 1978-03-06 1979-09-13 Asahi Chemical Ind PROCESS FOR THE PRODUCTION OF OCTAMETHYLCYCLOTETRASILOXANE
US4276425A (en) * 1978-09-12 1981-06-30 Wacker-Chemie Gmbh Process for preparing cyclic dimethylpolysiloxanes
EP0311766A2 (en) * 1987-08-14 1989-04-19 Wacker-Chemie Gmbh Preparation and use of mixtures with a high content of cyclosiloxanes
FR2723095A1 (en) * 1994-07-29 1996-02-02 Gen Electric PROCESS FOR THE PREPARATION OF CYCLIC SILOXANES BY CRACKING
NL1003475C2 (en) * 1996-07-01 1998-01-12 Rhone Poulenc Chimie Cyclic poly-di:organo-siloxane cpds. for prodn. of silicone(s)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5110972A (en) * 1991-07-18 1992-05-05 Tremco Incorporated Process for recycling silicone scrap and products relating thereto
DE19934374C1 (en) * 1999-07-22 2000-10-19 Ge Bayer Silicones Gmbh & Co Continuous production of cyclic dimethylsiloxanes, e.g. octamethylcyclotetrasiloxane used in silicone elastomer production, includes removal of monomethylsiloxy compounds before recycling unwanted homologues

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2908249A1 (en) * 1978-03-06 1979-09-13 Asahi Chemical Ind PROCESS FOR THE PRODUCTION OF OCTAMETHYLCYCLOTETRASILOXANE
FR2419297A1 (en) * 1978-03-06 1979-10-05 Asahi Chemical Ind OCTAMETHYLCYCLOTETRASILOXANE PRODUCTION PROCESS
US4197251A (en) 1978-03-06 1980-04-08 Asahi Kasei Kogyo Kabushiki Kaisha Process for producing octamethylcyclotetrasiloxane
US4276425A (en) * 1978-09-12 1981-06-30 Wacker-Chemie Gmbh Process for preparing cyclic dimethylpolysiloxanes
EP0311766A2 (en) * 1987-08-14 1989-04-19 Wacker-Chemie Gmbh Preparation and use of mixtures with a high content of cyclosiloxanes
EP0311766A3 (en) * 1987-08-14 1989-07-26 Wacker-Chemie Gmbh Preparation and use of mixtures with a high content of cyclosiloxanes
FR2723095A1 (en) * 1994-07-29 1996-02-02 Gen Electric PROCESS FOR THE PREPARATION OF CYCLIC SILOXANES BY CRACKING
NL1003475C2 (en) * 1996-07-01 1998-01-12 Rhone Poulenc Chimie Cyclic poly-di:organo-siloxane cpds. for prodn. of silicone(s)

Also Published As

Publication number Publication date
FR1176541A (en) 1959-04-13
BE558079A (en)
DE1083820B (en) 1960-06-23

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