Use of polymerization inhibitor compositions
The present invention relates to the use of at least two phenol derivatives jointly with at least one ancillary polymerization inhibitor which is different from these two phenol derivatives and particularly is selected from phenol derivatives, amine derivatives, thiazine derivatives, nitroso compounds, N-oxyl derivatives, metal salts, quinone derivatives, and mixtures thereof, to inhibit the polymerization of ethylenically unsaturated monomers comprising at least one heteroatom, it being also possible for a dispersant to be incorporated. The present invention also relates to a corresponding polymerization-inhibiting composition and to the corresponding process for preparing ethylenically unsaturated monomers comprising at least one heteroatom, and particularly acrylic monomers.
1. A method for inhibiting polymerization of ethylenically unsaturated monomers that comprise at least one heteroatom, comprising manufacturing, purifying, storing, and/or transporting such monomers in the presence of at least two phenol derivatives and at least one ancillary polymerization inhibitor which is different from the two phenol derivatives, wherein the two phenol derivatives are para-methoxyphenol and pyrocatechol and the at least one ancillary polymerization inhibitor comprises hydroquinone and phenothiazine as a mixture.
2. The method according to claim 1 wherein the method limits and/or prevents fouling of industrial equipment used in the preparation of the ethylenically unsaturated monomers.
3. The method according to claim 2 , wherein the method limits and/or prevents fouling of industrial equipment used during distillation of the ethylenically unsaturated monomers.
4. The method according to claim 1 , wherein the amount of the two phenol derivatives is effective to enhance the polymerization-inhibiting effectiveness of the at least one ancillary polymerization inhibitor.
5. The method according to claim 1 , wherein the monomers are manufactured, purified, stored, and/or transported in the presence of the at least two phenol derivatives, the at least one ancillary polymerization inhibitor, and, optionally, para-dimethoxybenzene.
6. The method according to claim 1 , wherein the two phenol derivatives are para-methoxyphenol and pyrocatechol, and the weight ratio of para-methoxyphenol to pyrocatechol is from 1 to 99.
7. The method according to claim 1 , wherein the two phenol derivatives and the at least one ancillary polymerization inhibitor are present in a total amount of from 20 ppm to 1%, relative to the total weight of the monomers, the two phenol derivatives, and the at least one polymerization inhibitor.
8. The method according to claim 1 , wherein the monomers are manufactured, purified, stored, and/or transported in the presence of the at least two phenol derivatives, the at least one ancillary polymerization inhibitor, and at least one dispersant.
9. The method according to claim 8 , wherein the dispersant is selected from sulfonates, esters, succinimides, tristyrylphenols, acrylates, amides, amines, imidazoline, phenates, phosphates, and mixtures thereof.
10. The method according to claim 1 , wherein the ethylenically unsaturated monomers comprising at least one heteroatom are selected from the group consisting of halogenated unsaturated monomers, acrylic monomers, unsaturated acrylic resins, unsaturated amides, unsaturated ethers, and vinylpyridines.