US2566956.Pdf

Patented Sept. 4, 1951 ... ??? .. 2,566,956 UNITED STATES PATENT office George Wesley Pedlow, Jr. and Carl Shelley. Miner, Jr., Evanston, Ill., assignors to Minne sota Mining & Manufacturing Company, St. Paul, Minn., a corporation of Delaware Application December 31, 1942, Serial No. 40,904 1 Claim. (Cl. 260-4488) 1. The present invention relates to organic silicon It will be noted that this procedure does not yield Compounds and to products or articles involving 'an alkoxy silicane, nor an alkoxy chloro sili the same, and to methods for producing such cane; rather it yields an alkyl silicane or an alkyl Compounds. chloro silicane, such as: - Certain of the organic silicon compounds in s C question may be regarded as silicon tetrachloride, \sic, SiCl4 (which is derivable from silica, SiO2), in which at least one of the chlorine atoms is re ' ... - ??” placed by an organic radical, particularly an in which the carbon atom of the alkyl group alkoxy radical, yielding, compounds such as (or of an aryl group) is joined directly to the sili ... (RO)2SiCl2 and where the compounds in ques con atom; whereas in alkoxy silicon compounds tion have certain special properties and novel there is an oxygen atom intervening between the '-characteristics and/or are adapted for new and carbon atom of the alkyl group and the silicon valuable uses. The invention as a Whole will atom, which materially alters the nature of the be more fully explained hereinafter. 5 product:: - Further, the Grignard reaction is very Heretofore others have produced certain or expensive and hence unsuitable for ordinary large ganic silicon containing products, starting with scale commercial operations, at least in many silicon tetrachloride, SiCl4. Silicon tetrachloride cases and, in fact, in most cases unless magne is a chemical product which has long been known. sium becomes much cheaper. This reaction also - It can readily be produced in different ways in 20 involves the use of large volumes of anhydrous cluding, by blowing chlorine through a tower ‘ether, which is not only expensive but is hazard packed With Sand and coke and of Controlled tem ous and difficult to handle. -" ' ? - - - - - .. `? •?’ - - …. perature and other conditions. Thus silicon tet Another procedure which has been tried is the rachloride is a readily available material. Wurtz Reaction, an ordinary application of which One material which has been known for quite 25 -Some time, and which is derivable from Silicon C tetrachloride, is ethyl orthosilicate, i. e. CH,Cl + 2Na + C-de-CI – CH-SiC), + 2NaCl . which may also be referred to as tetra-ethoxy That is, phenyl chloride (otherwise known as silicane. This can be produced by the reaction 30 chloro benzene) plus silicon tetrachloride plus of silicon tetrachloride and ethyl alcohol under sodium will (to some extent) tend to yield phenyl certain conditions, so that the ethoxy radical trichloro silicane plus Sodium chloride. replaces the chlorine and HCl is evolved. This However this reaction, where it is desired to ... reaction has not proved too difficult because the replace part of the chlorine atoms of silicon tet hydrogen chloride does not react readily with 35 rachloride with phenyl or other aryl or alkyl ethyl alcohol. In fact, HCl does not react readily groups, tends...to result in a mixture of all pOS with primary alcohols in general. sible phenylor other arylor alkyl Substituted.sili However hydrogen chloride is quite reactive canes. There is also a tendency for the phenyl with other alcohols; and this fact has interfered chloride, or equivalent, in the presence of sodium, with the production of interaction products of 40 to produce diphenyl, or equivalent, which fur silicon tetrachloride and alcohols, excepti for pri ther detracts from the practical worth of such a mary alcohols. For example, see “Alkyl Ortho process. For example, in endeavoring to pro silicates' by A. W. Dearing and E. Emmet Reid, duce Phi2SiCl2, i. e. diphenyl, dichloro silicane, we Journal American Chemical Society, vol. 50, have found that it is difficult to secure a yield 1928, page 3058: The writers tried one secondary better than 15-20 percent. -- alcohol, i. e. isopropyl alcohol, but were unable The Friedel-Crafts type of reaction may also to produce an alkyl silicate of any kind this way; be considered. A typical Friedel-Crafts reaction so they otherwise employed only primary alcohols is: - - - - - - - - - in their work. Alcohols other than primary alco 50 , " Al Cla hols have a natural tendency to form the corre * 3. - ?? + C2HC1 --> CH3-C2H5 -- HCl sponding alkyl chloride and SiO2 when it is at It might also be assumed that the following re tempted to react such an alcohol with silicon action will occur, but it has not been successfully tetrachloride. completed, insofar as we are aware: Other procedures have been employed in at SS - Al Cls tempts to produce certain so-called organic sili | 3. CBI : --; SiCl4 ----» : CHSiCls - HCl . con-containing compounds. Thus the Friedel-Crafts reaction appears un one such procedure (which has advantages for workable in this connection, the Wurtz reaction certain purposes) involves the use of the Grig appears, impractical from the point of view of nardtion, noteEugenereagent. For G. example, Rochow as Patent a general No. 2,258,218.0 illustra many commercial conditions, and the production 2,566,956 3 of normal alkoxy silicanes such as tetra-ethoxy has the unique characteristic of having alkoxy Silicane appeared unpromising because of the in groupS attached to Silicon, Where the compound stability of such products toward hydrolysis. Of itself is resistant to both neutral and alkaline hy the various reactions and products above dis drolysis. Compounds of this character, upon cuSSed, the Grignard reaction and the products 5 heating to moderate temperatures, above the produced thereby (having a carbon to silicon, . respective melting point of each, Will polymerize -C-Si-, linkage), in Spite of the high cost to form resins Which may be controlled to a clear of Such reaction, apparently appeared most colorleSS, Water-resistant fusible character. prOImiSing: See Eugene C. Rochow PatentS NoS. The tern alkoxy Silicane is used herein to des 2,258,218, 2,258,219, 2,258,220, 2,258,221 and O ignate compounds in which at least one of the va 2,258,222. lences of Silicon is taken up by an alkoxy group We have, however, discovered an important and the other Valences may be Satisfied by one or class of organic-silicon compounds which do not more groupS Or atoms Such as chlorine, oxygen, have molecules with a carbon to silicon linkage, hydroxyl, amino, alkoxy, alkyl, aryl, etc. and furthermore which have a carbon-oxygen Insofar as We are aWare no one prior to Our Silicon (-C-O-SI-) linkage and yet do not invention ever produced an alkoxy Silicane or have the short-comings. of normal alkyl ortho other organic-Silicon compound of any type (e.g. Silicates, Such as ethyl orthosilicates (also re an alkoxy chloro Silicane) Which could be hy ferred to as tetra-ethoxy silicane). We have drolyzed to produce a compound having alkoxy also found that we can produce organic-silicon groupS attached to Silicon, Which latter compound compounds, e. g. starting with Silicon tetrachlo is resistant to neutral and/or alkaline hydrolysis; ride (SiCl4), in which only a portion, e. g. two, neither has there ever been produced, insofar as of the chlorine atoms are replaced by alkoxy We are aWare, an alkoxy Silicane containing one groups. This we have been able to accomplish or more other groups or atoms (in addition to the by employing a tertiary alcohol, e. g. tertiary : 5 tert-alkoxy group or groupS), and Which corn butyl alcohol or tertiary-amyl alcohol, for reac pound is stable to Ordinary neutral or alkaline tion with Silicon tetrachloride (under particular hydrolysis. conditions which avoid the undesirable produc Saying Somewhat the Same thing in other tion of tertiary-butyl chloride, or the like, plus Words, insofar as We knoW no One prior to our SiO2). Insofar as we know, no one prior to our 30 invention ever produced an alkoxy chloro Silicane invention has ever reacted a tertiary alcohol with in which the chlorines can be removed by hydrol silicon tetrachloride; or produced organic silicon ysis, e.g. by alkaline hydrolysis, using an alkaline compounds such as we have been able to produce. material, Such as ammonia, or pyridine, which is We have furthermore, been able to carry out our soluble both in Water and in the alkoxy chloro operations with good yields (e.g. 80 percent or Silicane, where the alkoxy groups are stable, i. e. better). So as to replace two chlorine atoms of 35 unaffected by such hydrolysis. the silicon tetrachloride, instead of all four chlo It is an object of Our invention to produce al rine atoms, as in the making of ethyl orthosili koxy silicanes, especially tertiary-alkoxy sili cate, (C2H5O)4Si. By employing different condi canes, of the type above indicated, which can be tions we can also replace either one or three chlo 40 hydrolyzed to produce the corresponding alkoxy rine atoms, as desired. ... silicanes which are resistant to neutral and/or We have produced various compounds of the alkaline hydrolysis. It is also an object of our type just referred to, including, for example, di invention to produce alkoxy Silicanes, having tertiary-butoXy dichloro silicane, one or more other groups attached to Silicon in addition to the alkoxy group or groups, which ((CH3)3CO)2SiCl2 compounds are stable against neutral and alka di-tertiary-amoxy dichloro silicane, line hydrolysis. It is also an object to provide resins, as above indicated, by polymerizing the type of compound last-mentioned.

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