Process for producing polyoxymethylene
View Patent ↗A process for the polymerization of formaldehyde, comprising contacting formaldehyde in a hydrocarbon solution with an aliphatic anhydride and a quaternary ammonium salt polymerization initiator of the formula: R 1 R 2 R 3 R 4 N + X − where R 1 is an aliphatic or olefinic hydrocarbon group containing about 18 to about 25 carbon atoms; R 2 , R 3 , and R 4 are each methyl, ethyl, and/or propyl, such that the total number of carbon atoms in R 2 , R 3 , and R 4 combined is between 3 and 7; and X − is an organic anion.
1. An improved process for the polymerization of formaldehyde, in a hydrocarbon solution, the improvement comprising the presence of an aliphatic anhydride molecular weight control agent and a quaternary ammonium salt polymerization initiator of the formula:
R 1 R 2 R 3 R 4 N + X −
where R 1 is an aliphatic or olefinic hydrocarbon group containing about 18 to about 25 carbon atoms; R 2 , R 3 , and R 4 are each methyl, ethyl, and/or propyl, such that the total number of carbon atoms in R 2 ,R 3 , and R 4 combined is between 3 and 7; and X − is an organic anion.
2. The process of claim 1 , wherein the polymerization initiator is behenyltrimethylammonium acetate.
3. The process of claim 1 , wherein the aliphatic anhydride molecular weight control agent is acetic anhydride.
4. The process of claim 1 , wherein the hydrocarbon solvent is one or more aliphatic hydrocarbons or a mixture of one or more aliphatic hydrocarbons and one or more aromatic hydrocarbons.
5. The process of claim 4 , wherein the aliphatic hydrocarbons comprise hexane, cyclohexane, heptane, octane, or 2-methylliexane.
6. The process of claim 4 , wherein the aromatic hydrocarbons comprise benzene, toluene or xylene.
7. The process of claim 4 wherein the hydrocarbon solvent is heptane or a mixture of heptane and toluene.
8. The process of claim 1 wherein the organic anion X − is acetate.
9. The process of claim 1 , wherein the polymerization initiator is behenyltrimethylammonium acetate and the molecular weight control agent is acetic anhydride.