BE533700A - - Google Patents

Description

       

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   The present invention relates to a process for making siloxanes having alkoxy groups attached to terminal silicon atoms.



   Siloxane polymers of this type have also been referred to as end-blocked alkoxy siloxanes, and have heretofore been prepared by controlled hydrolysis of dialkoylsilanes, as disclosed in US Pat. America No. 2,415,389 of February 4, 1947. This process is difficult to regulate and gives a mixture of products.



  It is also difficult to form high viscosity blocked end siloxanes by this process.



   In accordance with the invention, end-blocked siloxanes can be prepared in a wide range of viscosities and molecular weights, and the process conditions can be controlled so as to provide siloxane polymers of desired characteristics. Thus, one aspect of the invention involves the polymerization of a lower molecular weight siloxane, such as cyclic tetramer of dimethyl siloxane, in the presence of a dialkoxy-silane. The molar ratio of siloxane to dialkylsilane used determines the viscosity and average molecular weight of the end-blocked siloxane with alkoxy groups.



   The invention is based on the discovery that compounds containing Si-O-C and Si = O-Si = bonds react with each other in the presence of alkaline catalysts with exchange of silicon atoms. This reaction is illustrated by the following general equation:
 EMI1.1
 ùsi-0-Si + Si 0. = C = Si 0-Si = + = Si 0-C =
Usually, the silicon-oxy-carbon bond is found in one compound, such as dimethyldiethoxysilane, and the silicon-oxy-silicon bond in another compound, such as cyclic dimethylsiloxane trimer or tetramer, but the invention can be demonstrated with compounds of the same type. - holding both types of bonds in a single molecule.

   Thus, diethyltetraethoxydisiloxane undergoes rearrangement when heated in the presence of an alkaline catalyst so as to form ethyltriethoxysilane and a polymer, as follows:
 EMI1.2
 And (Et0) 2Si0Si (OEt) zEt ----; a. EtSi (OEt) 3 + polymer
The usual embodiment of the invention comprises the heating in the presence of an alkaline catalyst of a siloxane free of alkoxy groups with an alkoxy-silane having at least one hydrocarbon radical attached to the silicon atom or with- a polysiloxane having at least one hydrocarbon radical and at least one alkoxy group attached to the same silicon atom. Under these conditions, polymeric siloxanes are formed with ends blocked by alkoxy groups.

   It is preferable that the siloxane free of alkoxy groups is a dialkyl- or diaryl-cyclic trimer or tetramer.



   The nature of these polymers depends on the raw materials. In one type, a dialkoxy-silane is reacted with a double-functional siloxane to form a linear polymer as follows:
R'2Si (OR ") 2 + n (R2SiO) x = R" O- (R2SiO) nx-SiR'2-OR "(I) or
R "O- (R2SiO) nx-SiR'2- (OSiR2) nx-OR" (II)
2 2

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In the above equation, ± represents the number of monomeric siloxane elements present in the starting siloxane (3 or 4 respectively for a trimer or tetrameric cyclic siloxane), n represents the number of molecules of cer siloxane entering the final siloxane polymer with ends blocked by alkoxy groups, and (nx) represents the average degree of polymerization,

   it being understood that the final polymer mixture contains larger molecules and smaller molecules than the average. R "represents an alkyl or alkenyl radical and R and R 'represent hydrocarbon radicals such as alkyl, vinyl, aryl
 EMI2.1
 or aralkyl. It is not known whether, in the final polymer, the radical (R ') 2Si of the dialkoxysilane is in the terminal position or in an intermediate position in the polymer chain, but its exact location is somewhat
 EMI2.2
 effect on the properties of the polymer. QnA'Ies radicals R and R 'are identical, structures I and II are identical. The most significant characteristic of polymers is that they contain the groups
 EMI2.3
 alkoxy terminals - # il.

   These alkoxy groups are capable of reacting subsequently, for example by hydrolysis or condensation.



   The molecular weight of the final polymer is determined by the charge ratio of the siloxane to the alkoxysilane, and the determined molecular weight of the lower polymers agrees well with the molecular weight calculated from the charge ratios. The molecular weights of the higher polymers are more difficult to determine, but the viscosity of the products, which is an indication of molecular weight, increases gradually with the molecular weight calculated from the charge ratios.

   Thus, the invention allows the production of siloxanes
 EMI2.4
 with ends blocked by groups of alsoxyde molecular weight and viscosities determined in advance, as shown by the following equations relating to representative preparations:
 EMI2.5
 (CHJ) zSi (ûf2H5) 2 + (Si (CHJ) 20) 4 = C2H50 (Si (CHJ) zO) 5C2H5, (CHJ) 2Si (002H5) 2 + 2 (Si (CHJ) 20) 4 = C2H50 (Si (CHJ) zO) 9C2H5 (CHJ) zSi (OC2H5) 2 + 8 (Si (CHJ) 20) 4 = cz 5otsi (cA3) zo) 33cz g5
To form another type of polymeric siloxane having alkoxy groups attached to terminal silicon atoms, a trialkoxysilane is reacted with a siloxane.

   By way of illustration, a type of
 EMI2.6
 polymer formed from a siloxyne of the (R2Sio) x type is made as follows: O (R SiO) R "RSi <R '<> 3 + 3 n (R2SiO) = R-'Si- I - 0 (RSSio) Rr '3 x O (RSiO) 1 / In this case, it is a branched chain polymer which is re =.
 EMI2.7
 shown, and R, R 'and R ", .s, z and nx have the meanings given. End-blocked alkoxy siloxane polymers prepared using triple-functional alkoxy silanes as conditioning agents. blocking ends also gradually increase in molecular weight and
 EMI2.8
 viscosity with increasing ratio of siloxane to trialkoxysilane charged.

   These polysiloxanes can be represented by the following general formula: (R'Si03) (R2SiO) z (RII) J in which R, R 'and R "have the meaning indicated above and is an integer equal to at least 2, and preferably equal to at least 8. This formula comprises not only the branched-chain polymers indicated above, but also the linear trialkoxypolysiloxanes having an alkoxy group attached to a silicon atom with a function.

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 triple located in an intermediate position in the chain, namely;
R "(SiR2O) 4OSiR'O (SiR2O) 4R"
GOLD"
A third type of polymer having an alkoxy group attached to a terminal silicon atom is formed by the reaction of a siloxane with a monoalkoxysilane.

   In this case, among other products, a siloxane polymer with an end blocked by a single alkoxy group is formed as follows:
R'3Si (OR ") + n (RZSiO) x = R'3Si- (R2SiO) nx-OR"
Mixtures of any of the above three types of polymers can also be obtained by reacting a siloxane with a mixture of alkoxysilanes, for example a mixture of any two of the compounds such as mono-alkoxysilanes, dialkoxysilanes and trialkysilanes. The molecular weight and viscosity of these mixtures can be determined by adjusting the molar ratio of siloxane to total molecules of alkoxysilanes used, and the properties of these mixtures are determined by the proportions in which the respective alkoxysilanes are used.



   A fourth type of polymer is obtained by reacting a tri-functional siloxane polymer of the (RSiO 3 / 2N) type with a trialkoxysilane. In this case, polymers are obtained whose viscosities differ from those of the starting polymers, and the polymers formed contain alkoxy groups.These groups allow them to combine with alkyd resins by exchange of esters between the alkoxy group and the groups hydroxyl present in the alkyd resin. This fourth type of reaction can be represented as follows, x being usually equal to at least 8:
 EMI3.1
 
The above equation indicates that in some cases a polymer with ends blocked by alkoxy groups of higher molecular weight forms.

   However, the viscosity and hence the molecular weight of the final polymer may be higher or lower than the initial mixture of trialkoxysilane and triple functional siloxane polymer, depending on the viscosity of the starting polymer. Cosity gives balanced products of higher viscosity and polymers of high viscosity give balanced products of lower viscosity. However, for the same molar ratio of triple functional siloxane polymer to trialkoxy silane, the final viscosity of the equilibrated products is about the same whether the viscosity of the starting polymer is high or low.



   It is also possible to form complex mixtures of end-blocked alkoxy siloxanes by reacting double-functional siloxanes and triple-functional siloxanes with mono-, di- or tri-alkoxysilanes or mixtures thereof.

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   Reactions between a siloxane free of alkoxy groups and an alkoxy silane occur by mixing the ingredients in the presence of an alkaline catalyst at room temperature, but the reaction is very slow. It is preferable to heat the reaction mixture to 50-200 ° C. in order to speed up the reaction. At a temperature of 150 ° C. the reaction is usually completed in two to three hours. As the alkaline catalyst, preference is given to potassium silanolate KO (Me2SiO K, which is prepared by heating potassium hydroxide with cyclic tetrameric dimethyl siloxane. These catalysts usually contain about 3%. by weight of potassium.

   The amount of this catalyst can vary from 0.3% to 10% by weight of the reaction mixture. Based on the potassium content, this represents from 0.01% to 0.30% of the weight of the potassium contained in the reaction mixture. However, other alkaline catalysts such as potassium hydroxide, sodium hydroxide, alkali metal alkoxides such as potassium methoxide and butoxide, tertiary amines and ammonium compounds can be used. quaternary such as tetramethyl ammonium hydroxide.



   Regardless of the viscous products desired, the reaction produces a small amount of light products which can be removed from the reaction mixture. To accurately determine the physical properties, it is necessary to remove these lightweight products, but this is not necessary for many industrial uses of products such as oils, intermediates, dielectrics and water repellants.



   The reaction should also be carried out under substantially anhydrous conditions since the presence of water causes undesirable hydrolysis reactions.



   The examples which follow are divided into different parts so as to illustrate the various embodiments of the invention.



   PART A
Examples 1 to 11.



  Reaction of dialkoxy-silanes with double-functional siloxanes Example 1 - Purified linear polymer with blocked ends.



   . pans a round bottom flask of 500 cc. 0.5 months (148 g) of cyclic tetrameric dimethylsiloxane, 0.1 mol (14.8 g.) of dimethyldiethoxysilane and 0.5 g are placed. of potassium dimethylsilanolate containing 3.% by weight of potassium. The flask is fitted with a reflux condenser and placed in a bath at constant temperature of 150 ° C. for 5 hours. The reactants are then cooled and filtered so as to remove a small amount of white solid suspended in the oil. The 162 g. polymer oil obtained are divided into two portions.



   I. One serving of 65 g. of the product has the following properties:
 EMI4.1
 
<tb> Viscosity <SEP> at <SEP> 25 C. <SEP> 16.9 <SEP> ce.
<tb>



  % <SEP> OC2H5 <SEP> in <SEP> weight <SEP> 5.3 <SEP> ¯ <SEP> 0.3%
<tb> Molecular <SEP> weight, calculated <SEP> <SEP> 1628
<tb> P.M. <SEP> diaprés <SEP> OC2H5 <SEP> 1695
<tb>
 
II. The 97gb portion of the product is rectified under reduced pressure at 150 ° C. for 15 minutes. 86 g are obtained. clear oil with the following properties:
 EMI4.2
 
<tb> Viscosity <SEP> at <SEP> 25 C. <SEP> 22.1 <SEP> cs.
<tb>
<tb>



  % <SEP> OC2H5 <SEP> in <SEP> weight <SEP> 5.4 <SEP> ¯ <SEP> 0.3%
<tb>
<tb> Molecular <SEP> weight, calculated <SEP> <SEP> 1628
<tb>
 

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 EMI5.1
 F.M. according to OCZHS 1655 P. M. by cryoscopy in cyclohexane 1495
The light fractions from the rectification are collected in a solid carbon dioxide collector, these fractions have the following properties:
 EMI5.2
 
<tb> Weight <SEP> 11 <SEP> g. <SEP> (Il, 3% <SEP> in <SEP> weight <SEP> of
<tb> oil)
<tb> n25 <SEP> 1.393 <SEP> (for <SEP> comparison
<tb>
 
 EMI5.3
 n2de (Me2SiO) 4 ;;; % OC2115 9 1.3943 (MeSiO),
The average molecular weight shown for this and other product is the weight calculated from the molar ratio of the end-blocking ethoxysilane to the siloxane present in the raw material.



   It will be noted that the product freed from the light fraction has a higher viscosity than that of the crude product. Molecular weights of the purified product were determined by three methods: calculation from charge ratios, cryoscopy and from ethoxy content assuming the molecule contains two ethoxy groups. Satisfactory agreement between the molecular weight values determined in these ways shows that the compound is a dialkoxy compound and that the molecular weight of the polymer is determined by the charge ratio of the reactants.



    Example 2 - Linear polymers with blocked ends of different viscosities.



   6.67 g are placed in a large test tube. of dimethyldiethoxysilane, 13.33 g. of cyclic tetrameric dimethylsiloxane and 0.1 g. potassium dimethyl silanolate as a catalyst (containing 3% by weight of potassium). We hermetically seal the test tube and heat it
 EMI5.4
 in an oil bath at 15000 for three hours. The polymer oil thus obtained, not rectified, has a viscosity of 2.2 cs. at 37 7C. The molecular weight measurement by cryoscopy in cyclohexane gives a value of 440
 EMI5.5
 (The calculated value referred to the amount of dimethyldiethoxysilane used as end blocking agent is 444.



   Using a method similar to that described above, samples of polymeric dimethylsiloxanes having ends blocked by alkoxy groups were prepared by applying varying amounts of dimethyldiethoxysilane as an end blocking agent. The results of these experiments are shown in Table I.



   TABLE I Base-catalyzed equilibration of the cyclic tetramer of dimethylsiloxane
 EMI5.6
 and dimethyldiethoxysilane at 15 ° C, for three hours
 EMI5.7
 ¯¯¯¯ Reagents Product ¯¯¯ ¯¯¯¯ Exp. Mols (Me2SiO) Catalyst s Viscosity Wt. molecular n Mols Me / m7 '- \ Silanolate de en es.

   Cal- MoIs Me 2 Si OEt 2 potassium (wt%) 37 l 98.08 OUJI- -Found gim
 EMI5.8
 
<tb> a <SEP> 4 <SEP> 0.5 <SEP> 2, <SEP> 2 <SEP> 1, <SEP> 2 <SEP> 444 <SEP> 440
<tb>
<tb> b <SEP> 8 <SEP> 0.5 <SEP> 4.8 <SEP> 2.3 <SEP> 740 <SEP> 709
<tb>
<tb> c <SEP> 16 <SEP> 0.5 <SEP> 10, <SEP> 6 <SEP> 4.7 <SEP> 1332 <SEP> 890
<tb>
<tb> d <SEP> 32 <SEP> 0.5 <SEP> 25.9 <SEP> 11.7 <SEP> 2516 <SEP> 1255
<tb>
<tb> e <SEP> 64 <SEP> 0.5 <SEP> 53.1 <SEP> - <SEP> 4884 <SEP> -
<tb>
<tb> f <SEP> 80 <SEP> 0.5 <SEP> 80.5 <SEP> - <SEP> 6068-
<tb>
<tb> g <SEP> 110 <SEP> 0.5 <SEP> 128.8 <SEP> - <SEP> 8288 <SEP> -
<tb>
<tb> h <SEP> 130 <SEP> 0.5 <SEP> 139.1- <SEP> 9768 <SEP> -
<tb>
 

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   # Contains 3% potassium by weight ## Cryoscopic values in cyclohexane ### After removing 9,

  6% light products, the molecular weight is 2394.



   It will be noted that the viscosities increase progressively with the load ratio, of (Me2SiO) / Me2Si (OEt2) and that there is satisfactory agreement between the molecular weights determined by cryoscopy (after elimination of the light fractions) and the calculated values. according to load reports. Experiment (a) in the table represents the data of the above experiment for the reaction of one mol of (Me2SiO) with one mol of Me2Si (OEt) 2, Me and Et representing respectively the methyl and ethyl radicals.



  Example 3 - Effect of reaction time on product viscosity.



   A series of experiments are carried out for various times.



  Here is a typical experience.



   23.68 g are placed in a large test tube. of tetrameric cyclic dimethylsiloxane, 1.48 g. of dimethyldiethoxysilane and 0.12 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The test piece is hermetically sealed and it is immersed in an oil bath at 150 ° C. for 5 hours. The viscosity of the reaction mixture after this time is 23.5 centistokes at 377C.



   Table II gives the results of various experiments and shows that the reaction is substantially complete within three hours.



   TABLE II Equilibration catalyzed by a cyclic tetramer base of dimethylsiloxane and of dimethyldiethoxysilane at 150 C.
 EMI6.1
 
<tb>



  Exp. <SEP> Month <SEP> (Me2SiO) <SEP> Catalyst <SEP> Time <SEP> Viscosity <SEP> of
<tb>
<tb>
<tb>
<tb>
<tb> n <SEP> Month <SEP> Me. <SEP> If (OEt). <SEP> silanolate <SEP> of equi- <SEP> product <SEP> (centi-
<tb>
<tb>
<tb>
<tb>
<tb> Mols <SEP> MeiSi (OEt) 2 <SEP> potassium <SEP> free <SEP> stokes <SEP> to <SEP> 37 7C.
<tb>
<tb>
<tb>
<tb>
<tb>



  (wt.%) <SEP> (hours)
<tb>
<tb>
<tb>
<tb> 32 <SEP> 0.5 <SEP> 1 <SEP> 23.6
<tb>
<tb>
<tb> b <SEP> 32 <SEP> 0.5 <SEP> 3 <SEP> 23.8
<tb>
<tb>
<tb> c <SEP> 32 <SEP> 0.5 <SEP> 5 <SEP> 23.5
<tb>
<tb>
<tb> d <SEP> 32 <SEP> 0.5 <SEP> 7 <SEP> 24.1
<tb>
<tb>
<tb> e <SEP> 32 <SEP> 0.5 <SEP> 24 <SEP> 25.8
<tb>
   Example 4 ... Effect of catalyst concentration.



   A series of tests were carried out using different catalyst concentrations using 15 g each time. of reagents and a molar ratio of (Me2SiO) / Me2Si (OEt) 2 of 64/1. Here is a typical experience.



   In a large 'provette we place 14.55 g. of cyclic dimethylsiloxane tetramer, 0.45 g. of dimethyldiethoxysilane and 0.208 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The test piece is hermetically sealed and it is immersed in an oil bath at 150 ° C. for 3 hours. The viscosity of the silicone oil thus obtained is 57 centistckes at 37 7 C.



   Table III below gives the results of these experiments.

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   TABLE III Base-catalyzed equilibration of cyclic dimethylsiloxane and dimethyldiethoxysilane at 150 ° C. for three hours (weight of the reaction mixture: 15 g.)
 EMI7.1
 
<tb> Exp. <SEP> Month <SEP> K <SEP> x <SEP> 10-4ss <SEP> form <SEP> Weight% <SEP> silanolate <SEP> of <SEP> K <SEP> viscosity
<tb>
<tb>
<tb>
<tb> n <SEP> of <SEP> KO (Me2SiO) xK <SEP> containing <SEP>% <SEP> pds. <SEP> of <SEP> cs.

   <SEP> 37 7 <SEP> c.
<tb>
<tb>
<tb>
<tb> e (array <SEP> 1) <SEP> - <SEP> 0.5 <SEP> 53.1
<tb>
<tb>
<tb> a <SEP> 1.6 <SEP> 1.2 <SEP> 57.0
<tb>
<tb>
<tb> b <SEP> 2.4 <SEP> 1.8 <SEP> 59.4
<tb>
<tb>
<tb> c <SEP> 3.1 <SEP> 2.3 <SEP> 61.3
<tb>
<tb>
<tb> d <SEP> 3.9 <SEP> 2.9 <SEP> 62.5
<tb>
<tb>
<tb> e <SEP> 4.7 <SEP> 3.5 <SEP> 64.6
<tb>
<tb>
<tb> f <SEP> 5.5 <SEP> 4.1 <SEP> 62.6
<tb>
<tb>
<tb> g <SEP> 6.3 <SEP> 4.7 <SEP> 64.5
<tb>
<tb>
<tb> h <SEP> 7.5 <SEP> 5.6 <SEP> 63.6
<tb>
<tb>
<tb> i <SEP> 10.0 <SEP> 7.5 <SEP> 69.2
<tb>
<tb>
<tb> j <SEP> 12.5 <SEP> 9.4
<tb>
 
These results show that a catalyst concentration of less than 1% by weight of potassium silanolate is effective for the production of the desired polymers.

   Although higher catalyst concentrations can be used, as seen in the table above, this is not recommended because the increased viscosity of the polymer can be caused by the loss. alkoxy groups, which would undesirably influence the subsequent condensation.



    Example 5 - Linear end-blocked polymers from crude siloxanes.



   The foregoing examples illustrate the preparation of end-blocked alkoxy group linear siloxane polymers prepared from cyclic tetrameric dimethylsiloxane. It is also possible to use raw materials from the hydrolyzation of dimethyl dichlorosilane, as shown below.



   In a flask fitted with a reflux condenser, 1110 g are placed. Chloride-free dimethyl hydrolyzate from dimethyl-dichlorosilane, viscosity 3500 centistokes at 25 ° C., 44 g. of chloride-free dimethyl-diethoxysilane, and 7.7 g. potassium silanolate as a catalyst (containing 3% by weight of potassium). The mixture is heated to 150 ° C. for 3 hours in an oil bath, then cooled to room temperature. The oil thus obtained is centrifuged so as to remove any suspended solid material which may be present. It has a viscosity of 2.7 cs at 3767 C.



   In another preparation in which the molar ratio of (MeSiO) to Me2Si (OEt) 2 is 12/1 instead of 5/1, the viscosity of the final product is 7.7 cs. 137 7 C.



   Example 6 - End-blocked linear polymer from cyclic diethylsiloxane trimer.



   Various experiments were carried out using trimeric cyclic diethylsiloxane equilibrated with dimethyldiethoxysilane and diethyldimethoxysilane. Here is a typical experience
In a 500 cc balloon. fitted with a stopper, 183.6 g.



  (0.6 mol) cyclic dimethylsiloxane trimer, 14.8 g. (0.1 mol) of diethyldimethoxysilane and 1 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The mixture is heated in an oil bath at 150 ° C. for three hours After the mixture has cooled to room temperature and centrifuged to remove the small

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 amount of solid in suspension, 19 gb of a clear oil with a viscosity of 152 cs are obtained. at 37 7 C.



   The following table gives the results of this experiment and another.



   TABLE IV Equilibration of the trimeric cydl diethylsiloxane with the alkoxysilanes at 150 ° C. for three hours.
 EMI8.1
 



  Exp. Blocking agent Months (Et2SiO) Silanolate Viscosity Weight iP of the ends of K (cat.) Es. to mol. aleo silane Month block agent. ds. 7 7C. CC. a Et2Si (OMe) 2 18 0.5 152 1984 b Me2Si (OEt) 2 30 0.5 403 3236
The above alkoxy-terminated diethylsiloxane oils are ungrounded and contain low boiling cyclic compounds.



    Example 7 - Linear end-blocked polymers from other dialkoxy-silanes.



   It has also been found that certain other double-functional alkoxy-silanes equilibrate in the presence of an alkali catalyst with the cyclic dimethylsiloxane tetramer to give linear oils with alkoxylated ends. Among those that have been tried, we can cite the
 EMI8.2
 diphenyldiethoxysilane, diethyldimethoxysilane, diethyldlalloxysilane, tetrameth ldiethoxydisiloxane, hexamethyl-diethoxytrisiloxane ot dimethyl-difeethylhexoxysilane. The results of the equilibrations with these various compounds are given in Table V.



   TABLE V Equilibration of the double-functional alkoxy-silanes with cyclic dimethyl-siloxane at 150 C in the presence of 0.5% of KO (MeSiO) K as catalyst
 EMI8.3
 
<tb> Reagents <SEP> ¯ <SEP> Product
<tb>
 
 EMI8.4
 Ezp, Agent Mols (Me2SiO) Viscosity in cs Wt. mol. blocking n ##### - #### 37 7 C. 98 8 C. calculated - ¯ Month aflo block .. a (C6H5) 2Si (0Et) 2 4 6.9 2.7 568 b (C6H5) 2Si (OEt) 2 8 9.2 3.8 864 c (C6H5) 2Si (oEt) 2 16 15.7 6.4 1456 d (C6H5) 2Si (OEt) 2 32 29.3 Il, 8 2640 e (C6H5) 2Si (OEt ) 2 64 60.8 25.0 5008 f (Etsi (0Me) 28 24.1 - 2220 g Me2Si (OCsHr7) 2: 8 7.2 - 850 h Me2i (OCH2-CH-CH2) 2 32 36.2 - 2568 i Et (Me2SiO) zEt 30: 22.2 - 2516 j EtO (Me2SiO) 3Et 29 23.8 - 2516
 EMI8.5
 S C8H17 = 2-ethylhexyl Here are the details of these experiments.

 <Desc / Clms Page number 9>

 



  Experiment a - In a large test tube, 11.84 g are placed. of cyclic dimethylsiloxane tetramer, 10.88 g. of diphenyldiethoxysilane and 0.12 g. potassium silanolate as a catalyst (containing 3% by weight of potassium). The test piece is sealed and left in an oil bath heated to 150 ° C. for three hours. The polymer with blocked ends thus obtained has a viscosity of 6.9 es. at 37 7 C.



  Experiment f - In a 500 cc flask. 206.2 g are placed. (0.7 mol) of cyclic dimethylsiloxane tetramer, 14.8 g (0.1 mol) of diethyldimethoxysilane and 1 g of potassium dimethylsilanolate as catalyst (containing 3% by weight of potassium). The flask is sealed and heated in an oil bath at 150 ° C. for 3 hours.



  After cooling to room temperature, the mixture is centrifuged to remove the. small amount of suspended solid matter. 220 g are obtained. of a clear oil with a viscosity of 24.1 cs. at 37 7 C.



  Experiment g- In a 500 cc flask. we place 148 g. (0.5 mol) cyclic dimethylsiloxane tetramer, 76.5 g. (0.25 mol) of dimethyl-bis (2-ethylhexoxy) silane and 0.75 g. of potassium dimethylsilanolate (containing 3% by weight of potassium. The flask is sealed and heated at 150 ° C. for 5 hours in an oil bath. After cooling to room temperature and centrifuging the mixture for removing the suspended solids, a clear oil is obtained with a viscosity of 7.2 centistokes at 37 ° C. The viscosity of the original mixture of reagents is 2.1 tbsp at 37 ° C.



   The above polymeric oil was also rectified to remove the light portions at 150 ° C. under 2 mm. of mercury, for one hour, after deactivation of the catalyst. The rectified oil has a viscosity of 7.7 cs. at 37 7 C.



    Example 8 - Linear end-blocked polymers from other double-functional cyclic siloxanes.



   Other trimeric and tetrameric cyclic siloxanes have been found to equilibrate with the dialkyl- or diaryl-dialkoxysilanes in the presence of an alkaline catalyst. Among the cyclic siloxanes used, mention will be made of trimeric cyclic phenylmethylsiloxane, trimeric cyclic ethylmethylsiloxane, mixtures of tetrameric cyclic dimethylsiloxane with cyclic diethylsiloxane trimer and with trimeric cyclic phenylnethylsiloxane. The results of the equilibrations with these various compounds are shown in Table VI.



   ,

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TABLE VI Equilibration of double-functional ethoxysilanes with cyclic siloxanes
 EMI10.1
 (Experiments carried out at 150% 1 for 3 to 5 hours using 0.5% by weight KO (Me2SiO) xK (containing -3% by weight K) as the catalyst.
 EMI10.2
 



  Ex. Cyclic siloxane Agent of Month (R, .Si) Viscosity Weight n used blocking Month ag. block. in cs. at . molecular
 EMI10.3
 
<tb> used <SEP> 25 C. <SEP> laire <SEP> cal-
<tb>
<tb> butt
<tb>
 
 EMI10.4
 a (MeO) 3 2Si (OEt) 2 3 84.9 680
 EMI10.5
 
<tb> b <SEP> "<SEP> 2 <SEP> 7 <SEP> 329.0 <SEP> 1204
<tb>
<tb> c <SEP> "<SEP>" <SEP> 12 <SEP> 694.2 <SEP> 1904
<tb>
<tb> d <SEP> 15 <SEP> 892.4 <SEP> 2312
<tb>
<tb> e <SEP> "<SEP>" <SEP> 30 <SEP> 1895 <SEP> 4352
<tb>
<tb> f <SEP> 50 <SEP> 3473 <SEP> 7072
<tb>
 
 EMI10.6
 g (EtszMeo) 3 MezSi (OEt) 2 4 4.3 500
 EMI10.7
 
<tb> h <SEP> "<SEP> 10 <SEP> 14.5 <SEP> 1028
<tb>
<tb> i <SEP> "<SEP> 12 <SEP> 17.8 <SEP> 1204
<tb>
 
 EMI10.8
 Il 20 41.6 1908
 EMI10.9
 
<tb> k <SEP> "<SEP> 50 <SEP> 119.2 <SEP> 4548
<tb>
<tb> 1 <SEP> "<SEP> 80 <SEP> 239.3 <SEP> 7188
<tb>
 
 EMI10.10
 m (Me Sip) 3 Me Si (OEt) 4 4,

  5 500 (] And n2 sio 3 Il 20..5 1028
 EMI10.11
 
<tb> "<SEP> 10 <SEP> 20.5 <SEP> 1028
<tb>
<tb> o <SEP> "<SEP>" <SEP> 12 <SEP> 22.3 <SEP> 1204
<tb>
<tb> p <SEP> "<SEP>" <SEP> 20 <SEP> 47.9 <SEP> 1908
<tb>
<tb> q <SEP> "<SEP>" <SEP> 50 <SEP> 124.1 <SEP> 4548
<tb>
<tb> r <SEP> "<SEP> 71 <SEP> 249.5 <SEP> 7114
<tb>
 
 EMI10.12
 s (Me2..iO) 4) 3E Me2Si (OEt) 2 4 9.4 568 (SsiMeo) 4)
 EMI10.13
 
<tb> t <SEP> 10 <SEP> 31.1 <SEP> 1178
<tb>
<tb> u <SEP> "<SEP> 12 <SEP> 42.5 <SEP> 1408
<tb>
<tb> v <SEP> "<SEP>" <SEP> 20 <SEP> 80.0 <SEP> 2248
<tb>
<tb> w <SEP> 50 <SEP> 113.1 <SEP> 5398
<tb>
 x Experiment carried out with a reaction time of 16 hours.
 EMI10.14
 SE Equimolar ratio of the two monomer elements (R 2SiO) 0 Phenyl radical.



  Here are details of various experiments.
 EMI10.15
 Experiment c = Polymer of phenylmethylsiloxane with ends blocked by
4th ethoxy groups.



   In a 500 cc balloon. 81.6 g are placed. (0.2 mol) cyclic phenylmethylsiloxane trimer, 13.6 g. (0.05 mol) of diphenyl-diethoxysilane and 0.48 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The flask is sealed and heated in an oil bath at 150 ° C. for serze hours.

   After cooling to room temperature, 95 g are obtained. of a clear oil pcs seducing the following properties:
 EMI10.16
 
<tb> Viscosity <SEP> to <SEP> 25 <SEP> C <SEP> 694.2 <SEP> cs.
<tb>
 
 EMI10.17
 % ethoJqr .k. 4.8 + 0.3%
 EMI10.18
 
<tb> Molecular <SEP> weight <SEP> Calculated <SEP> 1904 <SEP> - <SEP>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> according to <SEP> the <SEP> assay <SEP> of ethoxy <SEP> 1875
<tb>
 
The above oil (14.7 g.) Rectified under reduced pressure at 150 ° C. does not give light fractions.

 <Desc / Clms Page number 11>

 



    Experiment i - Polymer of ethylmethylsiloxane with ends blocked by ethoxy groups.



   Place in a 500 cc balloon. 105.6 g. (0.4 mol) cyclic ethylmethylsiloxane trimer, 14.8 g. (0.1 mol) of dimethyldiethoxysilane and 0.6 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The flask is sealed and heated in an oil bath at 150 ° C. for 5 hours. After cooling to room temperature, the product is filtered to remove a small amount of a white fluffy solid suspended in oil. 120 g are obtained. of a clear oil which is divided into two portions,
I. 99 of crude oil having the following properties:
 EMI11.1
 
<tb> Viscosity <SEP> to <SEP> 25 C <SEP> 17.8 <SEP> cs.
<tb>
<tb>
<tb>



  % <SEP> ethoxy <SEP> 6.8 <SEP> + <SEP> 0.2%
<tb>
<tb>
<tb> Molecular <SEP> weight <SEP> calculated <SEP> 1204
<tb>
<tb>
<tb> according to <SEP> the <SEP> assay <SEP> of ethoxy <SEP> 1325
<tb>
 
II. 21 g. of product rectified under reduced pressure at 150 ° C. for 20 minutes give 19 g. clear oil with the following properties
 EMI11.2
 
<tb> Viscosity <SEP> to <SEP> 25 C <SEP> 25.0 <SEP> cs.
<tb>
<tb>



  % <SEP> ethoxy <SEP> 6.0 <SEP> + <SEP> 0.2 <SEP>% <SEP>
<tb>
<tb> Molecular weight
<tb>
<tb> calculated <SEP> 1204
<tb>
<tb> according to <SEP> the <SEP> assay <SEP> of ethoxy <SEP> 1500
<tb>
 
The light fractions are collected in a carbon dioxide snow collector with a view to rectification; they have the following properties:
 EMI11.3
 
<tb> Weight <SEP>. <SEP> 2 <SEP> g <SEP> (10 <SEP>% <SEP> of oil)
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>% <SEP> ethoxy <SEP> 15.2 <SEP> + <SEP> 0.4 <SEP>% <SEP>
<tb>
 Experiment 0 — Dimethylsiloxane dimethylsiloxane polymer with ends blocked by ethoxy groups. ,
Place in a 500 cc balloon. 44.4 g.

   (0.15 mol) of tetrameric cyclic dimethylsiloxane 61.2 g (0.2 mol) of trimeric cyclic diethylsiloxane, 14.8 g (0.1 mol) of dimethyldiethoxysilane and 0.6 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The flask is sealed and heated in an oil bath at 150 ° C. for 5 hours. After cooling to room temperature, the product is filtered to remove a small amount of a white fluffy solid suspended in oil. 120g is obtained. of a limpid oil which is divided into two portions.



   1.100 g. crude oil having the following properties:
 EMI11.4
 
<tb> Viscosity <SEP> to <SEP> 25 C <SEP> 22.3 <SEP> cs.
<tb>
<tb>
<tb>
<tb>



  % <SEP> ethoxy <SEP> 6.7 <SEP> + <SEP> 0.3 <SEP>% <SEP>
<tb>
<tb>
<tb> Molecular <SEP> weight <SEP> calculated <SEP> 1204
<tb>
<tb>
<tb> according to <SEP> the <SEP> assay <SEP> of ethoxy <SEP> 1325
<tb>
 
II. 20 g. of product rectified under reduced pressure at 150 ° C. for 20 minutes, giving 19 g. clear oil with the following properties:
 EMI11.5
 
<tb> Viscosity <SEP> to <SEP> 25 C <SEP> 27.7 <SEP> cs.
<tb>
<tb>
<tb>



  % <SEP> ethoxy <SEP> 5.4 <SEP> + <SEP> 0.2 <SEP>% <SEP>
<tb>
<tb>
<tb> Molecular <SEP> weight <SEP> calculated <SEP> 1204 <SEP> - <SEP>
<tb>
<tb>
<tb> according to <SEP> the <SEP> assay <SEP> of ethoxy <SEP> 1662
<tb>
 

 <Desc / Clms Page number 12>

   Experiment w - Copolymer of dimethylsiloxane and-phenyl-methylsiloxane with ends blocked by ethoxy groups
In a 500 cc balloon. 29.6 g are placed. (0.1 mol) cyclic dimethylsiloxane tetramer, 54.4 g. (0.133 mol) cyclic phenyl-methylsiloxane trimer, 9.87 g. (0.067 mol) of dimethyl-diethoxysilane and 0.47 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The flask is sealed and heated in an oil bath at 150 ° C. for 5 hours.

   The product is cooled and 84 g are obtained. of clear oil which is divided into two portions.



   I. 69 g. crude oil having the following properties:
 EMI12.1
 
<tb> Viscosity <SEP> 42.5 <SEP> s.
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>



  % <SEP> ethoxy <SEP> 6.1 <SEP> 4 <SEP> 0.35
<tb>
<tb>
<tb>
<tb> Molecular weight
<tb>
<tb>
<tb>
<tb> Calculated <SEP> 1408
<tb>
<tb>
<tb>
<tb> according to <SEP> the <SEP> assay <SEP> of ethoxy <SEP> 1475
<tb>
 
II. 15 g. of product rectified under reduced pressure at 150 ° C. for 20 minutes, giving 14.7 g. clear oil with the following properties:
 EMI12.2
 
<tb> Viscosity <SEP> 51.2 <SEP> cs.
<tb>



  % <SEP> ethoxy <SEP> 5.4 <SEP>% <SEP>
<tb> Molecular <SEP> weight
<tb> Calculated <SEP> 1408
<tb> according to <SEP> the <SEP> assay <SEP> of ethoxy <SEP> 1662
<tb>
 Example 9 - Copolymers of dimethylsiloxane and diphenylsiloxane with ends blocked by ethoxy groups.



   In a 250 cc balloon. fitted with a rubber stopper, 99 g. (0.125 mol) tetrameric cyclic diphenylsiloxane, 37 g.



  (0.125 mol) cyclic dimethylsiloxane tetramer, 27.2 g. (0.1 mol) of diphenyldiethoxysilane and 0.82 g. potassium dimethyl silanolate as a catalyst (containing 3% by weight of potassium). The contents of the flask are heated to a temperature at which the tetrameric diphenylsiloxane melts. The flask is then placed in a bath at constant temperature of 150 ° C. for 4 hours. After cooling the mixture, 164 g are obtained. of a clear polymer oil with a viscosity of 1496 cs. at 25 C.



  Example 10 - Polymers of diphenylsiloxane with ends blocked by ethoxy groups.



   23.8 g are placed in a flask fitted with a rubber stopper.



  (0.03 mol) cyclic tetrameric diphenylsiloxane, 3.26 g. (0.012 mQl) of diphenyldiethoxysilane and 0.135 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The melt mixture is heated under argon and equilibrated at 150 ° C. for five hours. After cooling to room temperature, a waxy solid is obtained which softens at 60 ° C. and becomes a clear oil at 145 ° C.



  Example 11 - Polymers of phenylmethylsiloxane with ends blocked by amino-ethoxy groups.



   In a 500 cc balloon. fitted with a rubber stopper, 136 g. phenylmethylsiloxane hydrolyzate, 17.8 g. (0.1 mol) of b @ s- (2-aminoetoxydimethylsilane) and 0.77 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium).



  The flask is heated in a constant temperature bath at 150 ° C. for 4 hours. At the end of this time we obtain '150 g. of a clear polymer oil with a viscosity of 376 cs. at 25 C. and which contains 1.98% amino group (theory 2.08%). The molecular weight of the polymer is 1610 based on the assay of end amine groups (calculated molecular weight 1538).

 <Desc / Clms Page number 13>

 



    PART B Examples 12 and 13 Reaction of trialkoxysilanes with double-functional siloxanes.
 EMI13.1
 



  ¯Example 12 - Polymer with ends, "blocked by branched chains.



   In a 500 cc balloon. equipped with a reflux condenser, 0.45 mol (133.2 g.) of cyclic tetrameric dimethylsiloxane, 0.1 mol is placed
 EMI13.2
 (19.2 g.) Of ethyltriethoxysilane and 0.45 g. potassium dima 1-silanolate containing 3% by weight potassium. The flask is then placed in a bath at constant temperature at 150 ° C. for 5 hours. The product is cooled and filtered to remove a small amount of a white fluffy solid suspended in the oil.

   151 g are obtained. of a clear oil with the following properties:
 EMI13.3
 
<tb> Viscosity <SEP> to <SEP> 25PC <SEP> 13.5 <SEP> cs.
<tb>
 
 EMI13.4
 ethoxy 9.30.3%
 EMI13.5
 
<tb> Molecular <SEP> weight <SEP> Calculated <SEP> 1524
<tb>
<tb> according to <SEP> the <SEP> assay <SEP> of ethoxy <SEP> 1460
<tb>
 
Preparation of these polymers on a large scale gives products with more clearly defined properties. 49.385 kg are charged into a Pfaudler vessel with a capacity of 115 liters, fitted with a stirrer. a mixture of cyclic dimethylpolysiloxanes containing approximately 22% of tetramer, 20% of pentamer and 56% of higher cyclic polymers (of formula (R2SiO) in which n is at least equal to 6),
 EMI13.6
 7.082 kg. ethyltriethoxysilaHe and 19.5 g. of powdered potassium hydroxide.

   The stirrer is started and the temperature of the tank is brought to 150 ° C., a temperature which is maintained for 3 and a half hours.



  At the end of this time, the vessel is placed under reduced pressure and the light fractions are driven off under an absolute pressure of 50 mm. of mercury at a temperature between 125 and 250 C. It is eliminated in the form of light fractions 12 and 15% of the contents of the tank.



   The residue is a viscous oil with a molecular weight of 1500 (by cryoscopy). Its ethoxy content is at analysis 8.8% by weight, which agrees satisfactorily with the theoretical value.
 EMI13.7
 of 9% by weight for a trialkoxypo3ysiloxane of this molecular weight. Example 13 - End Blocked Siloxans with Branched Chain Alkoxy Groups from Trialkoxysilanes. '
Various triple-functional alkoxysilanes are balanced by means of cyclic tetrameric dimethylsiloxane in the presence of an alkaline catalyst so as to obtain polymers of the branched type containing at least a few structures of the type:

     
 EMI13.8
 o (Me2SiO) and x
 EMI13.9
 R - Si - o (Me2SiO) xET o (me2SiO) xET We have equilibrated the phenyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane and hexaetho: x; yd.is :: ll \ YIDtt'hart '& raLV4C c..c; ti7.1t11'3,10-cyclic xane tetramer. Here are the numerical indications relating to these operations (Table VII).

 <Desc / Clms Page number 14>

 



   TABLE VII Equilibration of the triple-functional alkoxysilanes with tetrameric cyclic dimethylsiloxane at 150 ° C. for 3 hours in the presence of 0.5% by weight
 EMI14.1
 of KO (Me2SiO) xK as catalyst.
 EMI14.2
 
<tb>



  Exp. <SEP> Agent <SEP> of <SEP> blocking <SEP> Month <SEP> (MeSiO) <SEP> Viscosity <SEP> Weight
<tb>
<tb>
<tb>
<tb>
<tb> N <SEP> of <SEP> ends <SEP> Months. <SEP> ag. <SEP> Block. <SEP> en <SEP> es. <SEP> molecular
<tb>
 
 EMI14.3
 ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯37 7 9808 calculated a EtSi (OEt), 8 5.2 2.4 782 b EtSi (oEt) 3 16 9.6 4.4 1374 c EtSi (OEt) 3 32 20.5 S, 8 2558 d EtSi (OEt) 3 64 4., 5 Ié, 0 4926 es ViSi (OEt) 3 8 4 , 7 2.1 780 f 31 Visi (OEt) 3 32 16.4 7.0 2556 gc 6H5SI (OEÎ) 3 8 6.3 2.8 830 h oHSsi (OEt) 3 32 23.2 9.7 2608 i (EtO) 3Sii 2C2H4 64 23.2 - 5090
 EMI14.4
 
<tb> CH2 = CH-
<tb>
 Here are operational details on various of these experiments.
 EMI14.5
 Experiment 17.76 g are placed in a large test-tube. Cyclic dimethylsiloxane tetramer, 5.76 g. of ethyl-tiniethoxysilane and 0.12 g.

   potassium dimethylsilanolate as a catalyst (containing 3% - potassium). The test tube is sealed and immersed in
 EMI14.6
 an oil bath at 150 C for 3 hours e = t-half. The polymer oil thus obtained has a viscosity of 5.2 cs. at 37 7 C.
 EMI14.7
 Experiment - In a large test tube we place 17.76 g. tetrameric cyclic dimethylsiloxane. 5.7 g. of vinyltriethoxysilane and 0.12 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The test piece is hermetically sealed and left in an oil bath at 150 ° C. During three hours. Poly- oil
 EMI14.8
 mother thus obtained has a viscosity of 4.7 es. at 37 lC.



  Experiment s - In a large test tube we place 17.76 g. of cyclic dimethylsiloxane tetramer, 7.2 g. of phenyltriethoxysilane and 0.12 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The test piece is hermetically sealed and left in an oil bath at 150 ° C. for 6 hours. Polymer oil
 EMI14.9
 thus obtained has a viscosity of 6.3 es. at 3 7 7 C.



  Experiment i - In a large test tube we place 14.2 g. Cyclic dimethylsiloxane tetramer, 1.06 g. d-1-hexaethoxydisilylethane and 0.2 g. potassium dimethylsilanolate as a catalyst (containing 3% by weight of potassium). The test piece is sealed and immersed in an oil bath at 150 ° C. for three hours. The polymer oil thus obtained has a viscosity of 23.2 cs. at 37 7C.



   PART C Equilibration of triple-functional polysiloxanes with trialkoxysilanes.



  Example 14-
The triple functional polysiloxanes equilibrate with the al-
 EMI14.10
 coxjF - Uanes in the presence of alkaline catalysts. This is shown by experiments between completely condensed ethylpolysiloxane and ethylethoxysilaneo. These experiments are listed in Table VIII.

 <Desc / Clms Page number 15>

 



   TABLE VIII Equilibration of EtSiO3 / 2 with EtSi (OEt) ,, in the presence of potassium butoxide as catalyst.



   Viscosity of the mixture in tbsp to 37 7
 EMI15.1
 
<tb> Exp. <SEP> Month <SEP> of <SEP> Month <SEP> of <SEP> Before <SEP> After
<tb> n <SEP> (EtSiO3 / 2) n <SEP> EtSi (OEt) 3 <SEP> balancing <SEP> balancing
<tb>
<tb>
<tb> a <SEP> 1 <SEP> 0.6 <SEP> 3 <SEP> 8.5
<tb> b <SEP> 1 <SEP> 0.3 <SEP> 112 <SEP> 106.0
<tb> c <SEP> 1 <SEP> 0.6 <SEP> 23 <SEP> 9.5
<tb> d <SEP> 1 <SEP> 0.9 <SEP> 10
<tb>
 à Sample is a solid resin of w / m / about 4500 ## lower w / w material.



   PART D
Equilibration of Polysiloxanes with Monoalkoxysilanes Example 15 Preparation of a linear polymer of dimethylsiloxane with ends blocked by both trimethylsilyl and ethoxy groups.



   In a 250 cc balloon. we place 88 g. chloride-free dimethyl hydrolyzate (viscosity at 25 C: 3500 cs.) obtained by hydrolyzate of dimethyldichlorosilane, 1.8 g. (0.1 mol) of trimethylethoxysilane and 0.5 g. potassium dimethylsilanolate as catalyst (containing 3% by weight of potassium). The flask is fitted with a reflux condenser and heated in a constant temperature oil bath at 150 ° C. for three hours. The product is cooled and filtered to remove a small amount of white solid suspended in the oil. A clear oil with a viscosity of 10.2 cs is obtained. at 25 C.



   Note that, in the example above, there are the following types of polymers with blocked ends:
1. EtO (Me2SiO) xEt
2. EtO (Me2SiO) xSiMe3
3. Me3SiO (Me2SiO) xSiMe3 with predominance of the second.



   PART E
Preparation of specific alkoxy silicones.



   At the low ratios of siloxane to alkoxysilanes, it is possible to form particular alkoxy compounds. Compounds of this type can also be formed by modifying the proportions of a silicon compound containing in the same molecule both Si-06-Si and Si-O-C bonds.



  Example 16 Modification of the proportions of 1,3-diethyltetraethoxy-disiloxane.



   In a 500 cc balloon. fitted with a fractionation column, 153 g of 1.3-diethyltetrethoxydisiloxane, 155 g, are placed. of tetrahydronaphthalene and 12 g. an ethanolic solution containing 19% by weight of sodium ethoxide. The mixture is heated under reflux for 2 and a half hours during which it distills 12.5 g. of material below 80 C. and 144 g. below 200 C, which is removed at the top of the column.



  The material remaining in the distillation flask is a clear liquid

 <Desc / Clms Page number 16>

 reddish-brown weighing 161 g. The distillation of 144. g. of matter dis-
 EMI16.1
 temperature between 80 and 200 C. gives 114 gb of ethylt, riethoxysilane, of boiling point of 159 to 161 C. density at 25 C. of 0.89, which represents a conversion of 89% of the ethoxy groups present in the initial compound into this compound.



  Example 17 - Equilibration of dimethyldiethoxysilane with tetrameric dimethylsiloxane.



   In a 250 cc balloon. connected to a Vigreux column, 74 g are placed. (0.25 mol) tetrameric dimethylsiloxane, 74 g. (0.5 mol) of dimethyldiethoxysilane and 0.8 g. of potassium silanolate as a catalyst (containing 3% by weight of potassium). Heat the mixture to
 EMI16.2
 1500C.-17500. for 3 and a half hours. The volatile products are then separated using this column under reduced pressure.

   The fractionation of 111 gb of volatile matter under atmospheric pressure gives the following results:
 EMI16.3
 
<tb> Fraction <SEP> Boiling point <SEP> <SEP> Density <SEP> to <SEP> 20 <SEP> Grams
<tb>
 
 EMI16.4
 lition, 2500. n
 EMI16.5
 
<tb> 1 <SEP> 107-113 <SEP> - <SEP> - <SEP> 19.4
<tb>
<tb> 2 <SEP> 113-160- <SEP> - <SEP> la, 7
<tb>
<tb>
<tb> 3 <SEP> 160-161 <SEP> 0.88 <SEP> 1.3881 <SEP> 10.2
<tb>
<tb>
<tb> 4 <SEP> 161-197.5 <SEP> - <SEP> - <SEP> 14.5
<tb>
 
 EMI16.6
 5 197.5-198.5 0.90 1.3920 35.7
 EMI16.7
 
<tb> residue - <SEP> - <SEP> - <SEP> 19.1
<tb>
 
Fraction 1 is mainly composed of recovered dimethyldiethoxysilane, fraction 3 of tetramethyldiethoxydisiloxane, and fraction 5 of hexamethyldiethoxytrisiloxane. Intermediate fractions are mixtures of these compounds.



  Example 18 - Preparation of trimethylethoxysilanes.



   In a 1000 cc balloon. we place 384 g. (1 mol) of dodecam-
 EMI16.8
 thylpentasiloxane (Dow.- Corning Corp., 2% viscosity dimethylsiloxane) 1.2 gb (1 mol) ethyltriethoxysilane and y-r.76 g. potassium dimethyl slanolate as a catalyst (containing 3% by weight of potassium). The flask is heated to reflux under a fractionation column and the low boiling material is removed overhead. We obtain a small quantity of material (10 g.) Boiling below
 EMI16.9
 75 C. and 183 g. of material boiling at 75s80 C.

   This represents a 77.5% conversion of all trimethylsilyl groups to trimethylethoxysilane, which is collected as a colorless liquid having the following properties:
 EMI16.10
 
<tb> Boiling point <SEP> <SEP> 75 <SEP> - <SEP> 76 C.
<tb>
<tb>
<tb> D25 <SEP> 0.75 <SEP> g./cc.
<tb>
<tb>
<tb>
<tb> n25D <SEP> 1.3715
<tb>
 
 EMI16.11
 Example 19 - Equilibration of ethyltriethoxysilane with tetrameric dimethylsiloxane.



   A mixture of 78.8 g is heated at 150 ° C. for 5 hours. (0.4 mol) of ethyltriethoxysilane and 59.2 g. (0.2 mol) of cyclic tetramer dimethylsiloxane containing 1.3 g. potassium silanolate as cstalyseuro After removal of the volatile material from the reaction mixture by a Vigreux column under reduced pressure at a flask temperature of 165 ° C. under 0.5 mm., it remains in the balloon an insoluble gel weighing
 EMI16.12
 25 g.

   The 112 g are redistilled. detelistillate using a fractionation column under atmospheric pressure.

 <Desc / Clms Page number 17>

 
 EMI17.1
 
<tb> Fraction <SEP> Pt. <SEP> boil., <SEP> C <SEP> n20d <SEP> Grams
<tb>
<tb>
<tb>
<tb>
<tb>
<tb>
<tb> 1 <SEP> 95 <SEP> - <SEP> 112.5 <SEP> - <SEP> 1.0
<tb>
<tb>
<tb>
<tb> 2 <SEP> 112, -5-114 <SEP> - <SEP> 180,
<tb>
<tb>
<tb>
<tb> 3 <SEP> 114 <SEP> - <SEP> 159 <SEP> - <SEP> 5.0
<tb>
<tb>
<tb>
<tb> 4 <SEP> 159 <SEP> - <SEP> 162 <SEP> 1.3898 <SEP> 17.3
<tb>
<tb>
<tb> 5 <SEP> 162 <SEP> - <SEP> 197 <SEP> - <SEP> 7.9
<tb>
<tb>
<tb>
<tb> 6 <SEP> 197 <SEP> - <SEP> 199 <SEP> 1.3942 <SEP> 23.5
<tb>
<tb>
<tb>
<tb> Residual <SEP> - <SEP> 35.2
<tb>
<tb>
<tb>
<tb> Loss- <SEP> - <SEP> 4.1
<tb>
 
In the above distillation, only fraction 2 (dimethyl-diethoxysilane)

   is obtained in a reasonably pure state. It represents
20 months percent of available ethoxy groups. Fraction 4 is a mixture of ethyltriethoxysilane and tetramethyl-diethoxydisiloxane. Fraction 6 is primarily hexamethyldiethoxytrisiloxane, but is impure.



   PART F Equilibration of polysiloxanes with other alkoxy silicones.



   Apart from simple mono-, di- or trialkoxysilanes, more complex molecules of the trialkoxysilane type, such as hexaethoxydisilylethane, (EtO) 3SiC2H4Si (OEt) 3 can also be used as end-blocking agents. Polysiloxanes can also be used. containing alkoxy groups attached to silicon.



  Example 20 - Preparation of a highly branched dimethylsiloxane oil using hexaethoxydisilylethane as an end blocking agent
In a 1 liter flask connected to a reflux condenser are placed 399.6 g of dimethyl hydrolyzate of dimethyldichlorosilane, viscosity of 3500 cs at 25 ° C. 106.2 g. of hexaethoxydisilylethane and 2.5 g. potassium silanolate as a catalyst (containing 3% by weight of potassium). The mixture is heated to 150 ° C. for three hours in an oil bath and then cooled to room temperature. The 500 g are centrifuged. of polymer oil obtained so as to eliminate the solid matter in suspension which it contains. Its viscosity is 11.2 cs. at 25 C.

   The product thus formed, like that of experiment (i), Table VII, is an example of a hexaalcoxypolysiloxane of formula (O3SiRSiO) (R'2 SiO) (R ") 6 in which R is a divalent hydrocarbon radical, R 'is a monovalent hydrocarbon radical, R "is an alkyl radical and is bonded to a silicon atom through an oxygen atom, and n is an integer equal to at least 6.



    Example 2] Preparation of a siloxane polymer containing an alkoxy group formed from dimethylsiloxane and phenylsiloxane elements.



   12.6 g are placed in a large test tube. of cyclic dimethylsiloxane tetramer, 8.25 g. of phenylmethoxypolysiloxane containing 17% by weight of OMe groups (OMe / Si ratio = 0.8) and 0.11 g. potassium silanolate as a catalyst (containing 3% by weight of potassium). The mixture is heated to 150 G. in an oil bath for three hours and then cooled to room temperature. Initially, the reagents are not completely miscible. However, the reaction mixture becomes clear after a short time of heating. A clear polymer oil is obtained with a viscosity of 267 cs. at 25 C.


    

Claims (1)

ABSTRACT. I - Process for manufacturing siloxane polymers with ends blocked by alkoxy groups, said process being characterized by the following points, separately or in combinations: 1) reacting under substantially anhydrous conditions and in the presence of an alkaline catalyst a siloxane containing at least one silicon-oxy-silicon bond and free of alkoxy groups attached to a silicon atom, with a silicon compound having at least a hydrocarbon radical and at least one alkoxy group attached to the same silicon atom; 2) the silicon compound is a polysiloxane; 3) the polysiloxane is an alkyl- and (or) a trimer or tetrameric cyclic arylsiloxane; 4) the siloxane has the formula (R) 2SiO x in which x is equal to 3 or 4 and is reacted with an alkoxysilane of formula (R) nSi (OR ') 4-n' R being in both formulas one monovalent hydrocarbon radical R-n ', an alkyl radical and n an integer of 1 to 3; 5) the molar ratio of the alkoxysilane to the reacted siloxane is from 1/1 to 1/100; 6) R, in both formulas, is a methyl, ethyl, or phenyl radical; 7) the alkaline catalyst is potassium silanolate; wherein 8) said silanolate has the formula KO (CH3) 2SiO K wherein y is a number such that the silanolate contains 3% by weight of potassium; 9) the alkoxysilane is a hexylalkoxysilane of formula (R'0) SiR "Si (OR ') in which R is a monovalent hydrocarbon radical, R' is an alkyl radial and R" is a divalent hydrocarbon radical. II - End-blocked siloxane polymers prepared by means of the process as above.