Continuous process for the production of low molecular weight polyethers with a dmc catalyst

A continuous process for the production of a polyoxyalkylene polyether polyol having a hydroxyl content of from about 3.4 to about 12.1% by weight comprising:

• (a) establishing oxyalkylation conditions in a continuous oxyalkylation reactor in the presence of a double metal cyanide catalyst;
• (b) continuously introducing alkylene oxide and a low molecular weight starter into the continuous oxyalkylation reactor, wherein the starter has at least two hydroxyl groups per molecule and an equivalent weight of up to 115;
• (c) recovering a partially oxyalkylated polyether polyol from the continuous oxyalkylation reactor;
• wherein (i) the oxyalkylation in the continuous oxyalkylation reactor occurs at a sufficiently high pressure to prevent deactivation of the DMC catalyst;
• (ii) the concentration of unreacted alkylene oxide in the contents of the continuous reactor is maintained at a level of from 1 to 3% by weight;
• and
• (iii) the hydroxyl content of the reactor contents is maintained at 3.4 to 12.1% by weight;
• and
• (d) allowing further reaction of the partially oxyalkylated polyether polyol which is recovered from the continuous oxyalkylation reactor to occur until the unreacted alkylene oxide content of the mixture is reduced to 0.001% or less by weight
• wherein the build ratio in the continuous oxyalkylation reactor is from 4.6 to 16.2 and the overall build ratio is from 4.6 to 16.2, and wherein the temperature of the reaction mixture in further reaction step (d) increases by up to 35° C. as a result of the exothermic polymerization reaction.

A continuous process for the production of a polyether polyol having a hydroxyl content of from about 3.4 to about 12.1% by weight, comprising:

• (a) continuously polymerizing at least one alkylene oxide in the presence of a double metal cyanide catalyst in a continuous reactor;
• (b) feeding a low molecular weight starter that has at least two hydroxyl groups per molecule and an equivalent weight of up to 115, and at least one alkylene oxide to the continuous reactor containing alkylene oxide and a double metal cyanide catalyst;
• recovering a partially oxyalkylated polyol mixture from the continuous reactor
• wherein (i) the continuous reactor is maintained at a pressure of from 45 to 55 psia, (ii) the concentration of unreacted alkylene oxide in the contents of the continuous reactor is maintained at a level of from 1 to 3% by weight, and (iii) the hydroxyl content of the reactor contents is maintained at 3.4 to 12.1% by weight;
• and
• (d) subsequently, the partially oxyalkylated polyol mixture which is withdrawn from the continuous reactor is permitted to further react until the unreacted alkylene oxide content of the mixture is reduced to 0.001% or less by weight
• wherein the build ratio in the continuous oxyalkylation reactor is from 4.6 to 16.2 and the overall build ratio is from 4.6 to 16.2, and wherein the temperature of the reaction mixture in the further reaction step increases by up to 35° C. as a result of the exothermic polymerization reaction.

A process for continuously polymerizing an alkylene oxide in the presence of a double metal cyanide polymerization catalyst to form a polyether polyol having a hydroxyl content of from about 3.4 to about 12.1% by weight, wherein:

• (a) in a first step, an initiator compound that has at least two hydroxyl groups per molecule and an equivalent weight of up to 115, and at least one alkylene oxide are fed to a continuous reactor containing a double metal cyanide catalyst, and a partially polymerized mixture is withdrawn from the continuous reactor;
• wherein (i) the continuous reactor is maintained at a pressure of from 45 to 55 psia, (ii) the concentration of unreacted alkylene oxide in the contents of the continuous reactor is maintained at a level of from 1 to 3% by weight, and (iii) the hydroxyl content of the reactor contents is maintained at 3.4 to 12.1% by weight, and
• (b) in a second step, the partially polymerized mixture which is withdrawn from the reactor in step (a) is permitted to further react until the unreacted alkylene oxide content of the mixture is reduced to 0.001% or less by weight
• wherein the build ratio in step (a) is from 4.6 to 16.2 and the overall build ratio is from 4.6 to 16.2, and wherein the temperature of the reaction mixture in step (b) increases by up to 35° C. as a result of the exothermic polymerization reaction.

A continuous process for the production of a polyoxyalkylene polyether polyol having an OH number of from 112 to 400 comprising:

• (1) establishing oxyalkylation conditions in a continuous oxyalkylation reactor in the presence of a double metal cyanide catalyst;
• (2) continuously introducing alkylene oxide and a low molecular weight starter into the reactor, the starter having a number average molecular weight of from 50 to 250;
• and
• (3) recovering a partially oxyalkylated polyether polyol from the continuous oxyalkylation reactor;
• wherein (i) the oxyalkylation is conducted in the continuous reactor at a sufficiently high pressure to prevent deactivation of the DMC catalyst;
• and
• (4) further reacting the partially oxyalkylated polyether polyol which is recovered from the continuous oxyalkylation reactor thereby forming the polyoxyalkylene polyether polyol having an OH number of from 112 to 400.

A process for continuously polymerizing an alkylene oxide in the presence of a double metal cyanide (DMC) polymerization catalyst to form a polyether polyol having a hydroxyl content of from about 3.4 to about 9.1% by weight, wherein

• (a) in a first step, an initiator compound that has at least two hydroxyl groups per molecule and an equivalent weight of up to 115 and at least one alkylene oxide are fed to a continuous reactor containing a double metal cyanide catalyst, and a partially polymerized mixture is withdrawn from the continuous reactor
• wherein (i) the continuous reactor is maintained at a pressure of from 45 to 55 psia, (ii) the concentration of unreacted alkylene oxide in the contents of the continuous reactor is maintained at a level of from 1 to 3% by weight, and (iii) the hydroxyl content of the reactor contents is maintained at 3.4 to 9.1% by weight, and
• (b) in a subsequent step, the partially polymerized mixture which is withdrawn from the reactor in step (a) is permitted to further react until the unreacted alkylene oxide content of the mixture is reduced to 0.001% or less by weight
• wherein the build ratio in step (a) is from 6.1 to 16.2 and the overall build ratio of from 6.1 to 16.2, and wherein the temperature of the reaction mixture in step (b) increases by up to about 24° C. as a result of the exothermic polymerization reaction.