阅读说明：本技术 用于抑制聚合的协同性组合 (Synergistic combinations for inhibiting polymerization ) 是由 谢小安 史永涛 张桂喜 张枚 于 2018-08-24 设计创作，主要内容包括：公开了一种协同性聚合抑制剂组合物,所述组合物具有铜盐和锰盐；铜盐或锰盐和阳离子聚合物；或吩噻嗪和锰盐。公开了一种抑制不饱和可聚合单体的聚合的方法,所述方法规定了将协同性聚合抑制剂组合物加入甲基丙烯酸制造系统或其组件,所述组合物具有铜盐和锰盐；铜盐或锰盐和阳离子聚合物；或吩噻嗪和锰盐。(A synergistic polymerization inhibitor composition is disclosed, having a copper salt and a manganese salt; copper or manganese salts and cationic polymers; or phenothiazine and manganese salts. A method of inhibiting polymerization of unsaturated polymerizable monomers is disclosed that provides for the addition of a synergistic polymerization inhibitor composition to a methacrylic acid production system or component thereof, the composition having a copper salt and a manganese salt; copper or manganese salts and cationic polymers; or phenothiazine and manganese salts.)

1. A synergistic polymerization inhibitor composition, said composition comprising:

a copper compound, and

a manganese compound.

2. The composition as claimed in claim 1, wherein the copper compound is a copper salt selected from the group consisting of: copper (II) acetate, copper (II) oxide, copper (II) sulfate, copper (II) chloride, copper (II) dithiocarbamate, copper (II) formate, copper (II) propionate, and copper (II) oleate.

3. The composition as claimed in claim 1, wherein the manganese compound is a manganese salt selected from the group consisting of: manganese (II) acetate, manganese (II) oxide, manganese (II) sulfate, manganese (II) chloride, manganese (II) dithiocarbamate, manganese (II) acetylacetonate, manganese (II) formate, manganese (II) propionate, manganese (II) oleate, manganese methylcyclopentadienyl tricarbonyl, manganese cyclopentadienyltricarbonyl, or a combination thereof.

4. The composition as claimed in claim 1, wherein the copper compound is at least 100 ppm.

5. The composition as claimed in claim 1, wherein the manganese compound is at least 100 ppm.

6. The composition as claimed in claim 1, wherein the copper compound is between about 0.01 wt% and about 50 wt%.

7. The composition as defined in claim 1, wherein the manganese compound is between about 0.01% and about 50% by weight.

8. A synergistic polymerization inhibitor composition, said composition comprising:

a copper compound or a manganese compound, and

a cationic polymer.

9. The composition as claimed in claim 8, wherein the copper compound is a copper salt selected from the group consisting of: copper (II) acetate, copper (II) oxide, copper (II) sulfate, copper (II) chloride, copper (II) dithiocarbamate, copper (II) formate, copper (II) propionate, and copper (II) oleate.

10. The composition as claimed in claim 8, wherein the manganese compound is a manganese salt selected from the group consisting of: manganese (II) acetate, manganese (II) oxide, manganese (II) sulfate, manganese (II) chloride, manganese (II) dithiocarbamate, manganese (II) acetylacetonate, manganese (II) formate, manganese (II) propionate, manganese (II) oleate, manganese methylcyclopentadienyl tricarbonyl, manganese cyclopentadienyltricarbonyl, or a combination thereof.

11. A composition as claimed in claim 8, wherein the cationic polymer has a molecular weight of greater than 500.

12. A composition as set forth in claim 8 wherein said cationic polymer comprises a plurality of repeating units and wherein at least 20% of said repeating units are positively charged.

13. The composition of claim 8, wherein the cationic polymer is [ Al (OH) ]_nCl_3-n]_mWherein n = 1.0 to 2.5 and m ≦ 20.

14. A composition as claimed in claim 8, wherein the cationic polymer is selected from the group consisting of: polydiallyldialkylammonium salts, polymers formed from amines and epihalohydrins or dihaloalkanes, epichlorohydrin-dialkylamine polymers, epichlorohydrin-dialkylamine-ethylenediamine polymers, polymers formed from vinyl trialkylammonium salts, polyaluminum salts, polymers of dialkylaminoalkyl (meth) acrylates, polymers of dialkylaminoalkyl (meth) acrylamides, poly [2- (acryloyloxy) ethyl ] trimethylammonium salts, or polymethacryloxyethyltrimethylammonium salts.

15. A composition as claimed in claim 8, wherein the copper compound or manganese compound in the composition is at least 100 ppm and the cationic polymer is at least 100 ppm.

16. The composition as recited in claim 8 wherein the copper compound or manganese compound is between about 0.01% and about 50% by weight.

17. A composition as claimed in claim 8, wherein the cationic polymer is between about 0.01% and about 90% by weight.

18. A synergistic polymerization inhibitor composition comprising:

phenothiazine, and

a manganese compound.

19. The composition as claimed in claim 18, wherein the manganese compound is a manganese salt selected from the group consisting of: manganese (II) acetate, manganese (II) oxide, manganese (II) sulfate, manganese (II) chloride, manganese (II) dithiocarbamate, manganese (II) acetylacetonate, manganese (II) formate, manganese (II) propionate, manganese (II) oleate, manganese methylcyclopentadienyl tricarbonyl, manganese cyclopentadienyltricarbonyl, or a combination thereof.

20. A composition as claimed in claim 18 wherein the phenothiazine is at least 100 ppm and the manganese compound is at least 100 ppm.

21. A composition as claimed in claim 18 wherein the phenothiazine is between about 0.01% and about 80% by weight.

22. A composition as in claim 18 wherein the manganese compound is between about 0.01% and about 50% by weight.

23. A method of inhibiting polymerization of an unsaturated polymerizable monomer, the method comprising:

adding a synergistic polymerization inhibitor composition to a monomer manufacturing system or component thereof, said composition comprising

Copper salts and manganese salts.

24. The method as claimed in claim 23, wherein the monomer is methacrylic acid and the synergistic polymerization inhibitor composition inhibits the polymerization of methacrylic acid.

25. The method as claimed in claim 23, wherein the monomer is an acrylate and the synergistic polymerization inhibitor composition inhibits acrylate polymerization.

26. The method as claimed in claim 23, wherein the monomer is a methacrylate and the synergistic polymerization inhibitor composition inhibits methacrylate polymerization.

27. A method as set forth in claim 23 wherein the monomer is acrolein and the synergistic polymerization inhibitor composition inhibits acrolein polymerization.

28. The method as claimed in claim 23, wherein the monomer is acrylonitrile and the synergistic polymerization inhibitor composition inhibits polymerization of acrylonitrile.

29. The method as claimed in claim 23, wherein the synergistic polymerization inhibitor composition is at least 10 ppm.

30. The method as claimed in claim 23, wherein the synergistic polymerization inhibitor composition is about 10% by weight.

31. A method of inhibiting polymerization of an unsaturated polymerizable monomer, the method comprising:

adding a synergistic polymerization inhibitor composition to a monomer manufacturing system or component thereof, said composition comprising

Copper or manganese salts and cationic polymers.

32. The method as claimed in claim 31, wherein the monomer is methacrylic acid and the synergistic polymerization inhibitor composition inhibits the polymerization of methacrylic acid.

33. The method as claimed in claim 31, wherein the monomer is an acrylate and the synergistic polymerization inhibitor composition inhibits acrylate polymerization.

34. The method as claimed in claim 31, wherein the monomer is a methacrylate and the synergistic polymerization inhibitor composition inhibits methacrylate polymerization.

35. A method as set forth in claim 31 wherein the monomer is acrolein and the synergistic polymerization inhibitor composition inhibits acrolein polymerization.

36. The method as claimed in claim 31, wherein the monomer is acrylonitrile and the synergistic polymerization inhibitor composition inhibits polymerization of acrylonitrile.

37. The method as claimed in claim 31, wherein the synergistic polymerization inhibitor composition is at least 10 ppm.

38. The method as claimed in claim 31, wherein the synergistic polymerization inhibitor composition is about 10% by weight.

39. A method of inhibiting polymerization of an unsaturated polymerizable monomer, the method comprising:

adding a synergistic polymerization inhibitor composition to a monomer manufacturing system or component thereof, said composition comprising

Phenothiazine and manganese salts.

40. The method as claimed in claim 39, wherein the monomer is methacrylic acid and the synergistic polymerization inhibitor composition inhibits the polymerization of methacrylic acid.

41. A method as set forth in claim 39 wherein the monomer is an acrylate and the synergistic polymerization inhibitor composition inhibits acrylate polymerization.

42. The method as claimed in claim 39, wherein the monomer is a methacrylate and the synergistic polymerization inhibitor composition inhibits methacrylate polymerization.

43. A method as set forth in claim 39 wherein the monomer is acrolein and the synergistic polymerization inhibitor composition inhibits acrolein polymerization.

44. A method as claimed in claim 39, wherein the monomer is acrylonitrile and the synergistic polymerization inhibitor composition inhibits the polymerization of acrylonitrile.

45. The method as claimed in claim 39, wherein the synergistic polymerization inhibitor composition is about 10% by weight.

46. The method as claimed in claim 39, wherein the synergistic polymerization inhibitor composition is at least 10 ppm.

Technical Field

The disclosed technology, generally described below, provides a synergistic composition for inhibiting polymerization of unsaturated polymerizable monomers, and more specifically, a synergistic composition for inhibiting polymerization of acrylic or methacrylic acid.

Background

One of the major problems in making unsaturated polymerizable monomers is the polymerization of the monomers. In the absence of effective polymerization inhibitors or dispersants, undesirable polymerization during manufacture can cause a number of problems, such as fouling or plugging of equipment, which can reduce operating time or increase the cost of cleaning the system. Therefore, effective polymerization inhibitors or dispersants are preferred in order to keep manufacturing smooth and safe.

There are various types of polymerization inhibitors or dispersants for this application, including phenols, hydroquinones, phenothiazines, copper salts, manganese salts, stable free radicals such as 4-hydroxy- (2,2,6, 6-tetramethylpiperidin-1-yl) oxy radical (or 4-hydroxy TEMPO), and the like. Such inhibitors or dispersants may be used alone or in combination to inhibit polymerization. There is a need for new inhibitors or dispersants with better inhibition efficiency.

Disclosure of Invention

The disclosed technology, generally described below, provides compositions and methods for synergistic polymerization inhibitors. In some embodiments, the composition comprises a copper compound and a manganese compound.

In some embodiments, the copper compound is a copper salt selected from the group consisting of: copper (II) acetate, copper (II) oxide, copper (II) sulfate, copper (II) chloride, copper (II) dithiocarbamate, copper (II) formate, copper (II) propionate, and copper (II) oleate. In some embodiments, the manganese compound is a manganese salt selected from the group consisting of: manganese (II) acetate, manganese (II) oxide, manganese (II) sulfate, manganese (II) chloride, manganese (II) dithiocarbamate, manganese (II) acetylacetonate, manganese (II) formate, manganese (II) propionate, manganese (II) oleate, manganese methylcyclopentadienyl tricarbonyl, manganese cyclopentadienyltricarbonyl, or a combination thereof.

In some embodiments, the copper compound is at least 100 ppm. In some embodiments, the manganese compound is at least 100 ppm. In some embodiments, the copper compound is between about 0.01 wt% and about 50 wt%. In some embodiments, the manganese compound is between about 0.01 wt% and about 50 wt%.

In yet another aspect of the disclosed technology, a synergistic polymerization inhibitor composition is provided. The composition comprises a copper compound or a manganese compound, and a cationic polymer.

In some embodiments, the copper compound is a copper salt selected from the group consisting of: copper (II) acetate, copper (II) oxide, copper (II) sulfate, copper (II) chloride, copper (II) dithiocarbamate, copper (II) formate, copper (II) propionate, and copper (II) oleate. In some embodiments, the manganese compound is a manganese salt selected from the group consisting of: manganese (II) acetate, manganese (II) oxide, manganese (II) sulfate, manganese (II) chloride, manganese (II) dithiocarbamate, manganese (II) acetylacetonate, manganese (II) formate, manganese (II) propionate, manganese (II) oleate, manganese methylcyclopentadienyl tricarbonyl, manganese cyclopentadienyltricarbonyl, or a combination thereof.

In some embodiments, the cationic polymer has a molecular weight greater than 500. In some embodiments, the cationic polymer comprises a plurality of repeat units, and wherein at least 20% of the repeat units are positively charged. In some embodiments, the cationic polymer is [ Al (OH) ]_nCl_3-n]_mWherein n = 1.0 to 2.5 and m ≦ 20.

In some embodiments, the cationic polymer is selected from the group consisting of: polydiallyldialkylammonium salts, polymers formed from amines and epihalohydrins or dihaloalkanes, epichlorohydrin-dialkylamine polymers, epichlorohydrin-dialkylamine-ethylenediamine polymers, polymers formed from vinyl trialkylammonium salts, polyaluminum salts, polymers of dialkylaminoalkyl (meth) acrylates, polymers of dialkylaminoalkyl (meth) acrylamides, poly [2- (acryloyloxy) ethyl ] trimethylammonium salts, or polymethacryloxyethyltrimethylammonium salts.

In some embodiments, the copper compound or manganese compound in the composition is at least 100 ppm and the cationic polymer is at least 100 ppm. In some embodiments, the copper compound or manganese compound is between about 0.01 wt% and about 50 wt%. In some embodiments, the cationic polymer is between about 0.01% and about 90% by weight.

In yet another aspect of the disclosed technology, a synergistic polymerization inhibitor composition is provided. The composition comprises phenothiazine and a manganese compound.

In some embodiments, the manganese compound is a manganese salt selected from the group consisting of: manganese (II) acetate, manganese (II) oxide, manganese (II) sulfate, manganese (II) chloride, manganese (II) dithiocarbamate, manganese (II) acetylacetonate, manganese (II) formate, manganese (II) propionate, manganese (II) oleate, manganese methylcyclopentadienyl tricarbonyl, manganese cyclopentadienyltricarbonyl, or a combination thereof.

In some embodiments, the phenothiazine is at least 100 ppm and the manganese compound is at least 100 ppm. In some embodiments, the phenothiazine is between about 0.01% and about 80% by weight. In some embodiments, the manganese compound is between about 0.01 wt% and about 50 wt%.

In yet another aspect of the disclosed technology, a method of inhibiting polymerization of an unsaturated polymerizable monomer is provided. The method includes adding a synergistic polymerization inhibitor composition to the monomer manufacturing system or a component thereof, the composition comprising a copper salt and a manganese salt.

In some embodiments, the monomer is methacrylic acid, and the synergistic polymerization inhibitor composition inhibits polymerization of methacrylic acid. In some embodiments, the monomer is an acrylate, and the synergistic polymerization inhibitor composition inhibits polymerization of the acrylate. In some embodiments, the monomer is a methacrylate, and the synergistic polymerization inhibitor composition inhibits methacrylate polymerization. In some embodiments, the monomer is acrolein and the synergistic polymerization inhibitor composition inhibits acrolein polymerization. In some embodiments, the monomer is acrylonitrile, and the synergistic polymerization inhibitor composition inhibits polymerization of the acrylonitrile.

In some embodiments, the synergistic polymerization inhibitor composition is at least 10 ppm. In some embodiments, the synergistic polymerization inhibitor composition is about 10% by weight.

In yet another aspect of the disclosed technology, a method of inhibiting polymerization of an unsaturated polymerizable monomer is provided. The method includes adding a synergistic polymerization inhibitor composition to the monomer manufacturing system or a component thereof, the composition comprising a copper or manganese salt and a cationic polymer.

In some embodiments, the monomer is methacrylic acid, and the synergistic polymerization inhibitor composition inhibits polymerization of methacrylic acid. In some embodiments, the monomer is an acrylate, and the synergistic polymerization inhibitor composition inhibits polymerization of the acrylate. In some embodiments, the monomer is a methacrylate, and the synergistic polymerization inhibitor composition inhibits methacrylate polymerization. In some embodiments, the monomer is acrolein and the synergistic polymerization inhibitor composition inhibits acrolein polymerization. In some embodiments, the monomer is acrylonitrile, and the synergistic polymerization inhibitor composition inhibits polymerization of the acrylonitrile.

In some embodiments, the synergistic polymerization inhibitor composition is at least 10 ppm. In some embodiments, the synergistic polymerization inhibitor composition is about 10% by weight.

In yet another aspect of the disclosed technology, a method of inhibiting polymerization of an unsaturated polymerizable monomer is provided. The method includes adding a synergistic polymerization inhibitor composition to the monomer manufacturing system or a component thereof, the composition comprising phenothiazine and a manganese salt.

In some embodiments, the monomer is methacrylic acid, and the synergistic polymerization inhibitor composition inhibits polymerization of methacrylic acid. In some embodiments, the monomer is an acrylate, and the synergistic polymerization inhibitor composition inhibits polymerization of the acrylate. In some embodiments, the monomer is a methacrylate, and the synergistic polymerization inhibitor composition inhibits methacrylate polymerization. In some embodiments, the monomer is acrolein and the synergistic polymerization inhibitor composition inhibits acrolein polymerization. In some embodiments, the monomer is acrylonitrile, and the synergistic polymerization inhibitor composition inhibits polymerization of the acrylonitrile.

In some embodiments, the synergistic polymerization inhibitor composition is about 10% by weight. In some embodiments, the synergistic polymerization inhibitor composition is at least 10 ppm.

Brief Description of Drawings

These and other features and advantages of the disclosed technology are now more particularly described in the embodiments that will now be described, by way of example, with reference to the accompanying schematic drawings in which:

FIG. 1 is a graph providing results of illustrative embodiments of the disclosed technology; and is

Fig. 2 is a graph providing results of illustrative embodiments of the disclosed technology.

Detailed description of the invention

The disclosed technology, generally described below, provides a synergistic composition for inhibiting polymerization of unsaturated polymerizable monomers, such as, but not limited to, acrylic acid, methacrylic acid, acrylate esters, acrolein, and/or acrylonitrile monomers. More specifically, the disclosed technology provides a synergistic composition for polymerization inhibition of acrylic acid and/or methacrylic acid.

With the disclosed synergistic compositions and methods, manufacturers involving the above-described monomers allow the system to remain in operation for longer periods of time before maintenance outages are required, which will increase productivity and also reduce the cost of cleaning equipment. This technique also reduces the safety risk from uncontrolled polymerization of the above monomers, such as, but not limited to, acrylic acid, methacrylic acid, acrylate esters, methacrylate esters, acrolein, and/or acrylonitrile monomers.

The present technology provides a synergistic polymerization inhibitor composition. In some embodiments, the synergistic polymeric composition comprises a copper compound and a manganese compound. These compounds may be water soluble or water insoluble.

In some embodiments, the copper compound is a copper salt and the manganese compound is a manganese salt. In some embodiments, the copper compound is selected from, but not limited to: copper (II) acetate, copper (II) oxide, copper (II) sulfate, copper (II) chloride, copper (II) dithiocarbamate, copper (II) formate, copper (II) propionate, copper (II) oleate, or a combination thereof. It will be appreciated by those skilled in the art that the copper compound may be selected from any copper (II) compound that provides a similar effect.

In some embodiments, the copper compound is at least 100 ppm. In other embodiments, the copper compound is at least 200 ppm, and in other embodiments, at least 500 ppm. In some embodiments, the copper compound is less than 500,000 ppm, and in other embodiments, the copper compound is less than 100,000 ppm. In some embodiments, the copper compound is in a range between about 500 ppm and about 100,000 ppm.

In some embodiments, the copper compound is between about 0.01 wt% and about 50 wt%. In other embodiments, the copper compound is between about 0.02 and 20 weight percent, and in other embodiments, between about 0.05 and 10 weight percent.

In some embodiments, the manganese compound is selected from, but not limited to: manganese (II) acetate, manganese (II) oxide, manganese (II) sulfate, manganese (II) chloride, manganese (II) dithiocarbamate, manganese (II) formate, manganese (II) propionate, manganese (II) oleate, or a combination thereof. It will be appreciated by those skilled in the art that the manganese compound may be selected from any manganese (II) compound that provides a similar effect.

In some embodiments, the manganese compound is at least 100 ppm. In other embodiments, the manganese compound is at least 200 ppm, and in other embodiments, at least 500 ppm. In some embodiments, the manganese compound is less than 500,000 ppm, and in other embodiments, the manganese compound is less than 100,000 ppm. In some embodiments, the manganese compound is between about 500 ppm and about 100,000 ppm.

In some embodiments, the manganese compound is between about 0.01 wt% and about 50 wt%. In other embodiments, the manganese compound is between about 0.02 and 20 weight percent, and in other embodiments, between about 0.05 and 10 weight percent.

In yet another aspect of the present technology, a synergistic polymerization inhibitor composition is provided. The synergistic polymerization inhibitor composition comprises a copper compound or a manganese compound, and a cationic polymer. In some embodiments, the synergistic polymerization inhibitor composition comprises a copper compound and a cationic polymer. In other embodiments, the synergistic polymerization inhibitor composition comprises a manganese compound and a cationic polymer.

In some embodiments, the synergistic polymerization inhibitor composition comprises a copper compound, wherein the copper compound comprises: copper (II) acetate, copper (II) oxide, copper (II) sulfate, copper (II) chloride, copper (II) dithiocarbamate, copper (II) formate, copper (II) propionate, copper (II) oleate, or a combination thereof.

In some embodiments, the manganese compound comprises: manganese (II) acetate, manganese (II) oxide, manganese (II) sulfate, manganese (II) chloride, manganese (II) dithiocarbamate, manganese (II) formate, manganese (II) propionate, manganese (II) oleate, or a combination thereof.

In some embodiments, the cationic polymer comprises: polydiallyldialkylammonium salts, polymers from amines and epihalohydrins or dihaloalkanes, epichlorohydrin-dialkylamine polymers, epichlorohydrin-dialkylamine-ethylenediamine polymers, polymers from vinyl trialkylammonium salts, polyaluminium salts, polymers of dialkylaminoalkyl (meth) acrylates, polymers of dialkylaminoalkyl (meth) acrylamides, poly [2- (acryloyloxy) ethyl ] ethylammonium salts]A trimethylammonium salt, a polymethacryloxyethyltrimethylammonium salt, or a combination thereof. In other embodiments, the cationic polymer is selected from, but not limited to, the group consisting of: polydiallyldialkylammonium salts, polymers from amines and epihalohydrins or dihaloalkanes, epichlorohydrin-dialkylamine polymers, epichlorohydrin-dialkylamine-ethylenediamine polymers, polymers from vinyl trialkylammonium salts, polyaluminium salts, polymers of dialkylaminoalkyl (meth) acrylates, polymers of dialkylaminoalkyl (meth) acrylamides, poly [2- (acryloyloxy) ethyl ] ethylammonium salts]A trimethylammonium salt, a polymethacryloxyethyltrimethylammonium salt, or a combination thereof. In some embodiments, the cationic polymer is [ Al (OH) ]_nCl_3-n]_mWherein n = 1.0 to2.5，m ≤ 20。

In some embodiments, the cationic polymer has a molecular weight greater than 500. In some embodiments, the cationic polymer comprises a plurality of repeating units. In such embodiments, at least 20% of the repeat units are positively charged, in other embodiments at least 50% are positively charged, and in other embodiments at least 80% are positively charged.

In some embodiments, the synergistic polymerization inhibitor composition comprises at least 100 ppm of a copper salt and at least 100 ppm of a cationic polymer. In some embodiments, the copper or manganese salt is between about 0.01 wt% and about 50 wt%. In some embodiments, the cationic polymer is between about 0.01% and about 90% by weight.

In yet another aspect of the present technology, a synergistic polymerization inhibitor composition comprising phenothiazine and manganese salts is provided.

In some embodiments, the manganese salt comprises: manganese (II) acetate, manganese (II) oxide, manganese (II) sulfate, manganese (II) chloride, manganese (II) dithiocarbamate, manganese (II) acetylacetonate, manganese (II) formate, manganese (II) propionate, manganese (II) oleate, manganese methylcyclopentadienyl tricarbonyl, manganese cyclopentadienyltricarbonyl, or a combination thereof.

In some embodiments, the phenothiazine is at least 100 ppm and the manganese salt is at least 100 ppm. In some embodiments, the phenothiazine is between about 0.01 and about 80 weight percent, in some embodiments, between about 0.02 and about 50 weight percent, and in other embodiments, between about 0.05 and 20 weight percent.

In some embodiments, the manganese salt is between about 0.01 and about 50 weight percent, in some embodiments, between about 0.02 and about 20 weight percent, and in other embodiments, between about 0.05 and 10 weight percent.

In yet another aspect of the present technology, a method of inhibiting polymerization of an unsaturated monomer is provided. In some embodiments, a method of inhibiting polymerization of acrylic acid and methacrylic acid is provided. It will be appreciated by those skilled in the art that the present method can inhibit the polymerization of other unsaturated polymerizable monomers such as, but not limited to, acrylate, methacrylate, acrolein, and/or acrylonitrile monomers.

The method includes adding the synergistic polymerization inhibitor composition to a manufacturing system of acrylic acid or similar monomers or components thereof. Examples of such manufacturing systems and components include, but are not limited to, a monomer absorption column, a monomer distillation column, and/or a monomer purification column. In some embodiments, a synergistic polymerization inhibitor is added to the crude monomer stream. In some embodiments, a synergistic polymerization inhibitor is added to the monomer-solvent mixed stream. In other embodiments, a synergistic polymerization inhibitor is added to the crude methacrylic acid or acrylic acid stream.

In some embodiments, the synergistic polymerization inhibitor composition of the present method comprises a copper salt and a manganese salt. The synergistic polymerization inhibitor composition inhibits the polymerization of acrylic acid, methacrylic acid, acrylates, methacrylates, acrolein, and/or acrylonitrile.

In some embodiments, the synergistic polymerization inhibitor composition of the present process is at least 10 ppm of the crude monomer stream. In some embodiments, the crude monomer stream is an acrylic acid or methacrylic acid stream. In other embodiments, the synergistic polymerization inhibitor composition is present at about 10% by weight of the crude monomer stream.

In yet another aspect of the present technology, a method of inhibiting polymerization of an unsaturated monomer is provided. In some embodiments, a method of inhibiting polymerization of methacrylic acid is provided. The method includes adding the synergistic polymerization inhibitor composition to the monomer manufacturing system or a component thereof. In some embodiments, the monomer manufacturing system is a methacrylic acid manufacturing system or a component thereof, wherein the composition comprises a copper or manganese salt and a cationic polymer.

In some embodiments, the synergistic polymerization inhibitor composition concentration is at least 10 ppm of the crude monomer stream. In some embodiments, the synergistic polymerization inhibitor composition is about 10% by weight of the crude monomer stream.

In yet another aspect of the present technology, a method of inhibiting methacrylic acid is provided. The method includes adding a synergistic polymerization inhibitor composition to the methacrylic acid production system or a component thereof, the composition comprising phenothiazine and a manganese salt.

In some embodiments, the synergistic polymerization inhibitor composition is at least 10 ppm of the crude monomer stream. In other embodiments, the synergistic polymerization inhibitor composition is about 10% by weight of the crude monomer stream.

Examples

The present invention will be further described in the following examples, which are to be regarded as illustrative and should not be construed to narrow the scope of the invention or to limit the scope to any particular inventive embodiment.

Acrylic acid polymerization inhibition was tested via an induction time test by heating acrylic acid with or without inhibitor in a hot oil bath and measuring the time before the mixture became cloudy or lost fluidity. For example, fluidity can be measured by gel formation and/or increased viscosity. Water or other solvents (such solvents may include, but are not limited to, toluene, methyl isobutyl ketone, or ethyl acetate) may be added to the acrylic acid for testing. The test can be performed under an inert gas atmosphere (i.e., nitrogen or argon) or in air or oxygen. The time before the mixture became cloudy or gelled (i.e., lost fluidity) was recorded as the induction time, with longer induction times indicating better polymerization inhibition efficiency.

In the following examples, the standardized test conditions were set as: 20 mL of distilled acrylic acid and 1 mL of deionized water in a test vial immersed in a hot oil bath set at 140 deg.C were heated, and the inhibitor for the test was added to the mixture and mixed thoroughly before the test vial was immersed in the hot oil bath. A50 mL/min sparge was maintained throughout the process. The time the mixture turned cloudy or gelled from clarification was recorded as the induction time.

A. Synergistic combination of copper and manganese salts

It was determined that the synergistic combination of manganese (Mn) salts (e.g., manganese (II) acetate) and copper (Cu) salts (e.g., copper (II) acetate) performed much better than the use of each metal salt alone. The synergistic composition also performs significantly better than the inhibitors currently on the market for acrylic acid manufacture. For example, such inhibitors include, but are not limited to, Hydroquinone (HQ), Phenothiazine (PTZ), MEHQ, 4-OH TEMPO, copper dithiocarbamate, nitrosobenzene, and/or manganese acetate.

Table 1 provides the results of testing synergistic combinations of manganese and copper salts. Table 1 shows the significant improvement in polymerization inhibition from the synergistic combination of Mn and Cu salts. Experiment 1 is a blank without any inhibitor addition. Experiment 9 contained a widely used combination of three inhibitors (hydroquinone (HQ), Phenothiazine (PTZ) and copper dithiocarbamate salt (CB)).

The results of experiments 2-7 in table 1 demonstrate that the combination of Mn and Cu compounds (i.e., salts) provides a synergistic effect and has better performance than either the commercially used inhibitor in experiment 9 or the single metals when used alone (experiments 2 and 3).

B. Synergistic combination of copper/manganese salts and cationic polymers

Experiments 10-17 in table 1 demonstrate that the synergistic combination of copper or manganese salts and cationic polymers provides significantly better polymerization inhibition than the inhibition products currently on the market for acrylic acid manufacture. Examples of such cationic polymers tested include polydiallyldimethylammonium chloride, polymers from epichlorohydrin-dimethylamine-ethylenediamine, polyaluminum chloride, and polymers from epichlorohydrin-dimethylamine. (see Table 2 below)

C. Synergistic combinations of Phenothiazine (PTZ) and manganese salts

Experiments 17-20 in table 1 demonstrate that the combination of PTZ and manganese compounds provides significantly better polymerization inhibition than the inhibition products currently on the market for acrylic acid manufacture.

While embodiments of the disclosed technology have been described, it is to be understood that the disclosure is not so limited and modifications may be made without departing from the disclosed technology. The scope of the disclosed technology is defined by the appended claims, and all devices, processes, and methods that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.