Environmentally friendly demulsifiers for crude oil emulsions

1. A demulsifler comprising about 5% to about 90% by weight of the demulsifier of a poly(tetramethylene glycol); and about 1% to about 50% by weight of the demulsifier of an alkylene glycol copolymer linked thereto by about 5% to about 90% by weight of the demulsifier of a difunctional coupling agent, wherein said difunctional coupling agent is a carboxylic diacid selected from the group consisting of adipic acid, succinic acid, glutaric acid, and terephthalic acid wherein the alkylene glycol copolymer further comprises an alkoxylated amine.

2. The demulsifier of claim 1 wherein the alkoxylated amine has the following formula:

wherein R 1 is selected from the group consisting of an alkyl radical having from 1 to about 23 carbon atoms and an alkenyl radical having from 2 to about 23 carbon atoms, R 2 is H or CH 3 , and a and b independently range from 1 to about 50.

3. The demulsifier of claim 2 wherein R 1 has from about 16 to about 18 carbon atoms, R 2 is H, a=8 and b=8.

4. A water-in-oil demulsifier comprising a poly(tetramethylene glycol); and an alkoxylated amine linked thereto by a difunctional coupling agent, wherein said difunctional coupling agent is a carboxylic diacid.

5. The demulsifier of claim 4 having the formula:

-[(A-B) m -(D-B)-] n -

wherein A is the poly(tetramethylene glycol), B is the difunctional coupling agent and D is the alkoxylated amine, m is in the range from about 0.01 to about 100, and n is an integer in the range from 1 to about 100.

6. The demulsifier of claim 5 wherein A is present from about 10% to about 90% by weight.

7. The demulsifier of claim 4 wherein the poly(tetramethylene glycol) is poly(tetrahydrofuran) having a molecular weight from about 100 to about 10,000.

8. The demulsifier of claim 4 wherein the difunctional coupling agent is selected from the group consisting of aliphatic carboxylic diacids having from 1 to about 20 carbon atoms and aromatic carboxylic diacids having from 1 to about 20 carbon atoms.

9. The demulsifier of claim 4 wherein the difunctional coupling agent is selected from the group consisting of adipic acid, succinic acid, glutaric acid and terephthalic acid.

10. The demulsifier of claim 4 wherein the demulsifler has a biodegradation of at least about 20%.

11. The demulsifier of claim 10 wherein the biodegradation is from about 25% to about 55%.

12. A water-in-oil demulsifier comprising a poly(tetramethylene glycol); and an alkoxylated amine linked thereto by a difunctional coupling agent, wherein the alkoxylated amine has the following formula:

wherein R 1 is selected from the group consisting of an alkyl radical having from 1 to about 23 carbon atoms and an alkenyl radical having from 2 to about 23 carbon atoms, R 2 is H or CH 3 , and a and b independently range from 1 to about 50.

13. The demulsifier of claim 12 wherein R 1 has from about 16 to about 18 carbon atoms, R 2 is H, a=8 and b=8.

14. A method of breaking an emulsion comprising oil and water comprising: contacting the emulsion with one or more demulsifiers selected from 1) a poly(tetramethylene glycol) and an alkylene glycol copolymer linked thereto by a difunctional coupling agent; 2) a poly(tetramethylene glycol) and an alkylene glycol copolymer that includes an alkoxylated amine, the alkylene glycol copolymer-alkoxylated amine linked to the poly(tetramethylene glycol) by a difunctional coupling agent; and 3) a poly(tetramethylene glycol) and an alkoxylated amine linked to the poly(tetramethylene glycol) by a difunctional coupling agent, wherein said difunctional coupling agent is a carboxylic diacid selected from the group consisting of adipic acid, succinic acid, glutaric acid, and terephthalic acid.

15. The method of claim 14 further comprising dispersing the demulsifier in a liquid carrier.

16. The method of claim 15 wherein the liquid carrier is selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons, glycols, glycol ethers, alcohols, water and fatty acid methyl esters or combinations thereof.

17. The method of claim 14 wherein the demulsifier is used in combination with one or more additional demulsifiers.

18. The method of claim 17 wherein the additional demulsifiers are selected from the group consisting of alkylphenol formaldehyde condensation products, polyalkylene glycols, organic sulfonates, alkoxylated alcohols, alkoxylated polyols, fatty acids, complex resin esters, alkoxylated fatty amines and alkoxylated polymeric amines.

19. The method of claim 14 wherein the emulsion is a water-in-oil emulsion.