CONTINUOUS PROCESS FOR PRODUCING POLYSILOXANE OILS UTILIZING A CARBON BLACK LYST

摘要

A continuous process for producing diorganopolysiloxane oils of 3 to 50,000 centipoise viscosity at 25.degree.C with a controlled hydroxy content comprising continuously transferring a fluid siloxane feed mixture into contact with a catalyst bed of acid-activated granular carbon black having a carbon to acid ratio of 10 parts to 1 to 40 parts to 1, which catalyst bed is maintained at 85 to 150.degree.C and over which catalyst bed there is maintained a vacuum of 5 to 200 millimeters of mercury . From this catalyst bed there is continually removed water. From the catalyst bed there is continually removed water. From the catalyst bed there continuously passes a product stream containing the desired diorganopolysiloxane product of 3 to 50,000 centipoise viscosity and various other low boiling siloxanes, which product stream contains 100 parts per million to 1% by weight of water and from 0 to 5 parts per million of acid. In a variation of this continuous process, the siloxane feed stream is passed into a first catalyst bed which may be in a column which is again filled with acid-activated granular carbon black with the same carbon to acid ratio as set forth above and over which there is a vacuum such that the water is continuously removed from the siloxane feed mixture so that there passes from said first catalyst bed a first product stream containing less than 100 parts per million of water. Said first product stream is passed into a second catalyst bed of acidactivated granular carbon black of the same carbon to acid ratio as set forth in the previous process and which second catalyst bed is again maintained at 85 to 150.degree.C and which is at least at atmospheric pressure. There is continually transferred from the second catalyst bed a second product stream containing the desired diorganopolysiloxanes of 3 to 50,000 centipoise viscosity at 25.degree.C and also having therein various low boiling siloxanes which second product stream has 0 to 50 parts per million of acid and less than 100 parts per million of water.