Oil miscible polyalkylene glycols and uses thereof
A polyalkylene glycol having an end-group of the general formula: in which each R 2 independently represents a hydroxyl, alkyl, alkenyl, aryl, heteroaryl, benzyl, or polyalkylene glycol group, and each R 3 independently represents a hydroxyl, alkyl, alkenyl, aryl, heteroaryl, benzyl, or polyalkylene glycol group; m is 0, 1, 2, 3, 4, 5 or 6; and n is 0, 1, 2 or 3. A lubricating oil composition comprising this polyalkylene glycol. A refrigerant composition comprising this polyalkylene glycol. A method of lubricating moving parts of an industrial or automotive system comprising applying a composition to the parts, wherein the composition comprises this polyalkylene glycol.
1. A polyalkylene glycol containing at least 4 alkylene glycol units and having an end-group of the general formula:
in which m is 2; and one R 2 represents a methyl group and the other R 2 represents a C 12-20 alkyl group; each R 3 independently represents a hydroxyl, alkyl, alkenyl, aryl, heteroaryl, benzyl, or polyalkylene glycol group; and n is 0, 1, 2 or 3.
2. The polyalkylene glycol as claimed in claim 1 , which has the general formula:
R[(C x H 2x O) p (C y H 2y O) q (C z H 2z O) r ]R 1 (II)
wherein
R is the group of formula I;
R 1 is a hydrogen atom, a C 1-20 alkyl group or a C 1-20 acyl group, or a group of formula I;
x is 2; y is 3; and z is an integer from 4 to 8;
and each of p, q and r independently is a number from 0 to 350, provided that the total of p, q and r is at least 4.
3. The polyalkylene glycol as claimed in claim 1 , in which the number of alkylene oxide monomer units having 4 or more carbon atoms is 0.
4. The polyalkylene glycol as claimed in claim 1 , in which the number of alkylene oxide monomer units having 2 carbon atoms is 0.
5. The polyalkylene glycol as claimed in claim 1 , in which the number of alkylene oxide monomer units having 3 carbon atoms is from 4 to 50.
6. The polyalkylene glycol as claimed in claim 1 , in which one end group of the formula I is present, and the or each other end group is H.
7. The polyalkylene glycol as claimed in claim 1 , in which n is 1, 2 or 3 and each R 3 is a methyl group.
8. The polyethylene glycol as claimed in claim 1 , in which the end group of formula I is derived from a tocopherol.
9. A lubricating oil composition comprising the polyalkylene glycol as claimed in claim 1 .
10. The lubricating oil composition as claimed in claim 9 , which comprises one or more known additives selected from the group consisting of those that provide improved antiwear properties, extreme pressure resistance, oxidation stability, corrosion inhibition, antifoaming, suppression of pourpoint, improvement of viscosity index, and reduction of acid content.
11. The lubricating oil composition as claimed in claim 9 , which also contains another lubricating oil.
12. The lubricating oil composition as claimed in claim 9 , which has a kinematic viscosity in the range of from 10 to 430 cSt at 40° C., a flashpoint of at least 260° C., and/or a pourpoint of at least −10° C.
13. A refrigerant composition which comprises a refrigerant together with a polyalkylene glycol as claimed in claim 1 .
14. A refrigeration system which comprises a refrigerant composition as claimed in claim 13 .
15. The refrigeration system as claimed in claim 14 , which includes a compressor in which said refrigerant composition is present.
16. A method of lubricating moving parts of an industrial or automotive system, which comprises applying to said moving parts the polyalkylene glycol as claimed in claim 1 .
17. A method of servicing an industrial or automotive system, which comprises adding the polyalkylene glycol as claimed in claim 1 .
18. The polyalkylene glycol as claimed in claim 1 , wherein said polyalkylene glycol is fully miscible with mineral oil.