Process for the production of silanol-stopped diorgano-polysiloxanes

Claim 2

A PROCESS FOR PRODUCING A SILANOL CHAIN-STOPPED DIORGANOPOLYSILOXANE HAVING A VISCOSITY OF 1,000 TO 10,000,000 CENTIPOISE AT 25*C AND A SILANOL CONTENT RANGING FROM 0.001 TO 0.5 PERCENT BY WEIGHT WHERE THE ORGANO GROUPS ARE SELECTED FROM THE CLASS CONSISTING OF MONOVALENT HYDROCARBON RADICALS, MONOVALENT HALOGENATED HYDROCARBON RADICALS AND CYANOALKYL RADICALS COMPRISING (A) CONTACTING A SILANOL CHAIN-STOPPED DIORGANOPOLYSILOXANE REACTANT HAVING A VISCOSITY OF 5 TO 900 CENTIPOISE AT 25*C CONTAINING UP TO 1.0 PERCENT BY WEIGHT OF TRIFUNCTIONAL SILOXANES AND UP TO 80 PERCENT BY WEIGHT OF CYCLIC SILOXANES WITH A CYCLIC POLYSILOXANE OF THE FORMULA,

Claim 3

The process of claim 1 wherein the cyclic siloxanes present in the silanol chain-stopped diorganopolysiloxane reactant have the formula, (R''2SiO)x where R'' is selected from the class consisting of monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals and cyanoalkyl radicals, x varies from 3 to 10.

Claim 4

The process of claim 1 wherein the silanol chain-stopped diorganopolysiloxane reactant has the formula,

Claim 5

The process of claim 1 wherein the reaction temperature is preferably at 120*C to 150*C, which reaction is allowed to proceed from 1 to 3 hours.

Claim 6

The process of claim 1 wherein the diorganopolysiloxane reactant has from 0.2 to 10 percent by weight of silanol groups therein.

Claim 7

The process of claim 1 wherein the silanol chain-stopped polysiloxane product has 0.1 to 0.5 percent by weight of silanol groups therein.

Claim 8

The process of claim 1 wherein the final product has the formula,

Claim 9

The process of claim 1 wherein the catalyst has been activated with sulfuric acid.

Claim 10

The process of claim 1 wherein the catalyst comprises from 0.1 to 90 percent by volume of the reaction area.

Claim 11

The process of claim 7 wherein the acid that is used to activate the catalyst has a pH below 5.

Claim 12

The process of claim 7 wherein after the reaction has proceeded to completion, the solid catalyst is separated from the liquid reaction product and the liquid reaction product is neutralized with a base before the stripping of the liquid by-products.

Claim 13

The process of claim 1 wherein said process is carried out in a batch procedure.

Claim 14

The process of claim 1 wherein the reactants are circulated through a column containing the solid catalyst and the effluent from said coLumn is continuously recycled through said column until the effluent reaches the desired viscosity.

Claim 15

The process of claim 11 wherein the base used to neutralize the liquid reaction product is NaHCO3.

Claim 16

The process of claim 11 wherein the cation exchange resin catalyst is a sulfonated polystyrene.

Claim 17

The process of claim 1 wherein the catalyst is sulfuric acid absorbed on a porous neutral solid.

Claim 18

The process of claim 7 wherein R is selected from the class consisting of lower alkyl, alkenyl and aryl.

Claim 19

The process of claim 1 wherein R is selected from lower alkyl, alkenyl and aryl.

Claim 20

The process of claim 3 wherein R is selected from lower alkyl, alkenyl and aryl.

Claim 21

The process of claim 2 wherein R'' is selected from lower alkyl, alkenyl and aryl.

Claim 22

A continuous process for producing a silanol chain-stopped diorganopolysiloxane reactant product having a viscosity of 1,000 to 10,000,000 centipoise at 25*C where the organo groups are selected from the class consisting of monovalent hydrocarbon radicals, monovalent halogenated hydrocarbon radicals and cyanoalkyl radicals comprising (a) hydrolyzing a silane of the formula R2SiX2 having up to 1.0 percent by weight of a trifunctional silane present therein of the formula, RSiX3 with dilute acid-water mixture of a pH that varies from 0.1 to 5, where R is selected from monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals and cyanoalkyl radicals and X is halogen, (b) separating the silane layer from the acid-water layer to obtain a silanol chain-stopped diorganopolysiloxane reactant having a viscosity of 5 to 900 centipoise at 25*C containing up to 1.0 percent by weight of trifunctional siloxanes and up to 80 percent by weight of cyclic siloxanes; (c) hydrolyzing a silane of the formula, R2SiX2 where R and X are as previously defined, with a dilute acid-water mixture; (d) separating the silane layer from the acid-water layer; (e) adding a strong base to the silane layer of step (c); (f) heating the silane layer of step (e) at a temperature in the range of 125*C to 175*C and collecting overhead, cyclic polysiloxane reactants of the formula, (R2SiO)n where R is as previously defined, n varies from 3 to 10; (g) contacting the silanol chain-stopped diorganopolysiloxane reactant having a viscosity of 5 to 900 centipoise at 25*C of step (b) with the cyclic polysiloxane reactant of step (f) in the presence of 0.1 to 75 percent by weight of the total mixture of a solid catalyst selected from the class consisting of acid activated carbon, acid activated clay and cation exchange resin thereon in the temperature range of 50*C to 200*C; (h) separating the reaction product from the catalyst, and (i) removing the volatiles from the reaction product which is a silanol chain-stopped diorganopolysiloxane having a viscosity of 1,000 to 10, 000,000 centipoise at 25*C.

Claim 23

A continuous process for producing a silanol chain-stopped diorganopolysiloxane reactant product having a viscosity of 1,000 to 10,000,000 centipoise at 25*C where the organo groups are selected from the class consisting of monovalent hydrocarbon radicals, monovalent halogenated hydrocarbon radicals and cyanoalkyl radicals comprising (a) hydrolyzing a silane of the formula R2SiX2 having up to 1.0 percent by weight of a trifunctional silane present therein of the formula, RSiX3 with dilute acid-water mixture of a pH that varies from 0.1 to 5, where R is selected from monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals and cyanoalkyl radicals and X is halogen, (b) separating the silane layer from the acid-water layer to obtain a silanol chain-stopped diorganopolysiloxane reactant having a viscosity of 5 to 900 centipoise at 25*C containing up to 1.0 percent by weight of trifunctional siloxanes and up to 80 percent by weight of cyclic siloxanes; (c) hydrolyzing a silane of the formula, R2SiX2 where R and X are as previously defined, with a dilute acid-water mixture; (d) separating the silane layer from the acid-water layer; (e) adding a strong base to the silane layer of step (c); (f) heating the silane layer of step (e) at a temperature in the range of 125*C to 175*C and collecting overhead, cyclic polysiloxane reactants of the formula, (R2SiO)n where R is as previously defined, n varies from 3 to 10; (g) contacting the silanol chain-stopped diorganopolysiloxane reactant having a viscosity of 5 to 900 centipoise at 25*C of step (b) with the cyclic polysiloxane reactant of step (f) in the presence of 0.1 to 75 percent by weight of the total mixture of a solid catalyst selected from the class consisting of acid activated carbon, acid activated clay and cation exchange resin thereon in the temperature range of 50*C to 200*C; (h) separating the reaction product from the catalyst, and (i) removing the volatiles from the reaction product which is a silanol chain-stopped diorganopolysiloxane having a viscosity of 1,000 to 10, 000,000 centipoise at 25*C.

Claim 24

The process of claim 21 wherein the solid catalyst is acid activated montmorillonite.

Claim 25

The process of claim 21 wherein the catalyst comprises from 0.1 to 90 percent by volume of the reaction area.

Claim 26

The process of claim 21 wherein the silanol chain-stopped diorganopolysiloxane reaction product has a silanol content of 0.001 to 0.5 percent by weight.

Claim 27

A process for producing a silanol chain-stopped diorganopolysiloxane having a viscosity of 1,000 to 10,000,000 centipoise at 25*C and a silanol content ranging from 0.001 to 5 percent by weight where the organo groups are selected from the class consisting of monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals and cyanoalkyl radicals comprising reacting cyclic polysiloxanes of tHe formula, (R2SiO)n with water at a concentration of 100 parts per million to less than 2 percent by weight where the R radicals are selected from the class consisting of monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals and cyanoalkyl radicals, n varies from 3 to 10, in the presence of 0.1 to 75 percent by weight of the total mixture of a solid catalyst selected from the class consisting of acid activated carbon, and acid activated clay in the temperature range of 50*C to 200*C.

Claim 28

A process for producing a silanol chain-stopped diorganopolysiloxane having a viscosity of 1,000 to 10,000,000 centipoise at 25*C and a silanol content ranging from 0.001 to 5 percent by weight where the organo groups are selected from the class consisting of monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals and cyanoalkyl radicals comprising reacting cyclic polysiloxanes of tHe formula, (R2SiO)n with water at a concentration of 100 parts per million to less than 2 percent by weight where the R radicals are selected from the class consisting of monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals and cyanoalkyl radicals, n varies from 3 to 10, in the presence of 0.1 to 75 percent by weight of the total mixture of a solid catalyst selected from the class consisting of acid activated carbon, and acid activated clay in the temperature range of 50*C to 200*C.

Claim 29

The process of claim 25 wherein the formula of the cyclic polysiloxane, n varies from 3 to 5.

Claim 30

The process of claim 25 wherein after said reaction has been completed, futher comprising filtering out said solid catalyst and then stripping out of the reaction mixture the remaining cyclic polysiloxanes.

Claim 31

The process of claim 25, wherein after said reaction has been completed, further comprising adding to the reaction mixture a neutralizing agent for the solid catalyst selected from the class consisting of NH4OH,

Claim 32

The process of claim 25 wherein the water is present at a concentration of 0.05 percent by weight to less tha 2 percent by weight.

Claim 33

The process of claim 25 wherein the reaction temperature is at 120*C to 100*C which reaction is allowed to proceed for 1 to 3 hours.

Claim 34

The process of claim 25 wherein said solid catalyst has been activated with sulfuric acid.

Claim 35

The process of claim 25 wherein said catalyst comprises from 0.1 to 90 percent by volume of the total mixture.

Claim 36

The process of claim 25 wherein the acid that is used to activate said solid catalyst has a pH below 5.

Claim 37

The process of claim 25 wherein the reactants are circulated continuously through a column containing said solid catalyst such that effluent emanating from said column is the desired product.

Claim 38

The process of claim 25 wherein said catalyst is sulfonic acid absorbed on a porous neutral solid.

Claim 39

The process of claim 25 wherein the R radical is selected from the class consisting of lower alkyl, alkenyl and aryl.

Claim 40

The process of claim 25 wherein said solid catalyst is acid-activated montomorillonite.

Claim 41

The process of claim 1 wherein prior to stripping the volatiles from the reaction mixture, further comprising adding to the reaction mixture a neutralizing agent for the solid catalyst selected from the class consisting of NH4OH, R4NH2,