Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
2001-01-19
2002-09-10
Moore, Margaret (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C556S460000, C528S032000
Reexamination Certificate
active
06448360
ABSTRACT:
BACKGROUND OF INVENTION
The present invention is a process for producing high-purity cyclic siloxane. More specifically, it is a process for producing high-purity cyclic siloxane by reducing the amount of silanol-containing linear siloxane contained as an impurity in cyclic siloxane. Cyclic siloxane can be prepared by the hydrolysis and condensation of diorganodichlorosilane or diorganocyclosilazane, and organopolysiloxane can be obtained by polymerizing such cyclic siloxane. However, linear siloxanes or silanes containing silanol groups are contained in the cyclic siloxane as impurities, and it is known that such silanes or linear siloxanes inhibit an increase in the molecular weight of the organopolysiloxane.
The authors of the present invention have attempted to use distillation in order to separate the silanol-containing linear siloxane contained in cyclic siloxane in the process of forming high molecular weight organopolysiloxane by polymerizing a cyclic siloxane having methyl groups and alkenyl groups having 6 to 14 carbon atoms. However due to the high boiling point of cyclic siloxane it has proved difficult to obtain high-purity cyclic siloxane.
It is an object of the present invention to provide a process for the production of high-purity cyclic siloxane by reducing the amount of silanol-containing linear siloxane contained as an impurity in cyclic siloxane having alkyl groups and alkenyl groups 6 to 14 carbon atoms.
SUMMARY OF INVENTION
The present invention is a process for the production of a cyclic siloxane described by formula
(R
1
(CH
3
)SiO)
d
comprising reacting in the presence of an alkali catalyst a siloxane mixture comprising a silane or a linear siloxane described by general formula
HO(R
1
(CH
3
)SiO)
b
H
and a cyclic siloxane described by general formula
(R
1
(CH
3
)SiO)
c
,
where R
1
is an alkenyl group having 6 to 14 carbon atoms, b is an integer of one or greater, c is an integer of 3 or greater, and d is an integer of 3 or greater.
REFERENCES:
patent: 2860152 (1958-11-01), Fletcher
patent: 3846464 (1974-11-01), Razzano
patent: 4197251 (1980-04-01), Hirakawa et al.
patent: 4689420 (1987-08-01), Baile et al.
patent: 4764631 (1988-08-01), Halm et al.
patent: 5109093 (1992-04-01), Rees et al.
patent: 5188899 (1993-02-01), Matsumoto et al.
patent: 5420325 (1995-05-01), Razzano et al.
patent: 5670689 (1997-09-01), Allandrieu et al.
patent: 6303811 (2001-10-01), Krahnke et al.
patent: 845554 (1960-08-01), None
patent: 42-8949 (1964-01-01), None
patent: 48-88199 (1973-11-01), None
patent: 49-92025 (1974-09-01), None
patent: 49-124067 (1974-11-01), None
patent: 54-090120 (1979-07-01), None
patent: 54-117491 (1979-09-01), None
patent: 55-38898 (1980-03-01), None
patent: 59-222495 (1984-12-01), None
patent: 2-91126 (1990-09-01), None
Higuchi Norikatsu
Maeshima Junichi
Okawa Tadashi
Takemasa Takao
De Cesare Jim L.
Dow Corning Toray Silicone Co. Ltd.
Moore Margaret
Scaduto Patricia M.
Troy Timothy J.
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