Organic compounds -- part of the class 532-570 series – Organic compounds – Silicon containing
Patent
1989-03-31
1991-02-05
Shaver, Paul F.
Organic compounds -- part of the class 532-570 series
Organic compounds
Silicon containing
C07F 710, C07F 718
Patent
active
049906429
DESCRIPTION:
BRIEF SUMMARY
The subject of the present invention relates to the production of oximosilanes by a rapid, economical and safe method that obviates the use of solvents.
It is known that oximosilanes can be produced by inducing a reaction of organochlorosilanes with oximes in the presence of suitable acid acceptors and solvents (U.S. Pat. Nos. 3,962,160, 3,441,583, 3,341,486, 3,817,909, DE-AS 13 01 140, DE-AS 11 20 690, DE-AS 12 55 924, FR-PS 11 18 495, EP-PS 0 036 262, W. Noll, Chemie und Technologie der Silikone, Seite 342, Verlag Chemie, Weilheim 1968).
The byproducts resulting from the use of this known method will be, depending upon the acid acceptor employed, quaternary ammonium salts such as ammonium chloride or amine hydrochloride. Due to the inevitable formation of such salts during the reaction, it is necessary, in order to be able to produce an acceptable crystal paste, that a large quantity of solvent be added to act as a surfactant. After the reaction has ended, the resulting oximosilane is separated from the salt formed during the reaction, and the salt then washed with large quantities of solvent. The fact that these salts cannot be economically washed away gives rise to the great dsadvantage that a considerable quantity of the desired end product, i.e. oximosilane, is absorbed onto their surface.
The desired oximosilane, which is contained in the filtrate, remains in the bottoms after the solvent is driven off. Subsequent distillation of the oximosilane yields the pure end product.
It has been shown, in practice, that residues containing such salts and present in the oximosilane bottoms can, during the subsequent distillation procedure, cause the explosive disintegration of the oximosilane through a Beckmann rearrangement. This phenomenon has been treated in the report of Leslie J. Tyler, Vice President and Research Director of Dow Corning Company, (published in C+E News, issue of 2/9/1974).
The literature describes a number of processes that avoid the formation of such salts. In this vein, DE-OS 27 19 008 sheds light on the reaction of a substituted aminosilane, e.g. ethyl tri(cyclohexylamino) silane or methyl-tri (secondary butyl-amino) silane with methyl ethylketoxime, whereafter the thus formed cyclohexylamine or secondary butylamine is distilled off so as to produce a ketoximosilane, whereby the residual distillate, the oximosilane, can be used without further treatment to produce coloured or transparent silicon sealants. Such a process does not, however, solve the present problem, because the offending salts, already issuing from the production of the aminosilanes, renders this method, too, uneconomical.
Described in JP-PS 80-016008 (C.A. (1980), 92-199928) is the reaction of alkoxisilanes, preferably silicontetraalkoxisilanes aided by a transesterification catalyst from the cyclo-diaza undazene series, with ketoximes. It has been shown, however, that the rather sluggish advance of such reactions coupled with the formation of a plurality of different substitute products causes such reactions to be extremely slow. Such reactions, moreover, being ineffective facilitators of alkoxi group replacement, render the corresponding process incapable of providing an economical solution to the difficulties related to the production of tetra and trifunctional oximosilanes.
U.S. Pat. Nos. 3,697,568 describes iminoxiorganosilanes and a process for their production. Such iminoxisilanes distinguish themselves from the substance produced according to the invention in that they feature not only the oxime residue but also an additional glycol-ether residue. In order to produce such compounds, either a halogen silane or an acyloxisilane is converted with an oxime in the presence of ammonia or a primary alkylamine or arylamine in an inert diluent (claims 12 and 13). As illustrated by the examples given, the use of a nitrogen-containing base in an inert diluent for the purpose of enabling the reaction to completely run its course, is an unavoidable necessity. Example 6 of this publication describes the reaction of methyltri
REFERENCES:
patent: 3189576 (1965-06-01), Sweet
patent: 3448136 (1969-06-01), Paude et al.
patent: 3697568 (1972-10-01), Boissieras et al.
patent: 4033991 (1977-07-01), Shinohara et al.
Haring Horst
Shaver Paul F.
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