Surfactant compounds

1. An oligoester surfactant compound which includes residues of:

i) a C 8 to C 30 alkenyl succinic anhydride, acid or reactive derivative;

ii) a polyol having at least 3 OH groups; and

iii) optionally, esterified residues of a fatty acid;

wherein the oligoester surfactant compound comprises on average at least one free hydroxyl group per polyol residue.

2. An oligoester surfactant compound which is the reaction product of:

i) a C 8 to C 30 alkenyl succinic anhydride, acid or reactive derivative;

ii) a polyol having at least 3 OH groups; and

iii) optionally a fatty monocarboxylic acid or a reactive derivative;

wherein the oligoester surfactant compound comprises on average at least one free hydroxyl group per polyol residue.

3. A compound as claimed in claim 1 wherein the polyol has from 4 to 6 carbon atoms and at least 4 hydroxyl groups.

4. A compound as claimed in claim 3 wherein the polyol is sorbitol, maltitol, isomaltitol, isomalt, or lactitol.

5. A compound as claimed in claim 1 of the formula (I)

R 1 —[OR 2 O(O)C.C(HR 3 ).(HR 4 )C.C(O)] m —R 5   (I)

wherein:

R 1 is H, or a group R 6 (O)C—;

each R 2 is independently a C 3 to C 10 hydrocarbyl group, having at least one hydroxyl group which is either substituent free or esterified with a fatty acid residue of the formula R 6′ (O)C—, where R 6′ is independently as defined for R 6 , or an alk(en)yl succinic terminated oligoester group of the formula —[O(O)C.C(HR 3′ ).(HR 4′ )C.C(O)OR 2′ ] m —R 1′ , where R 1′ , R 2′ , R 3′ , R 4′ , and m′ are independently as defined for R 1 , R 2 , R 3′ , R 4′ , and m′ respectively;

independently for each pair of groups R 3 and R 4 on adjacent carbon atoms, one is a C 6 to C 30 alkenyl or alkyl group and the other is hydrogen;

R 5 is —OH, —OM, wherein M is a salt forming metal, an amine or ammonium group, a group —OR 7 , or a group —OR 2 O—R 7 ;

R 6 is a C 1 to C 21 aliphatic hydrocarbyl group;

R 7 is H or a group —C(O)R 6 where R 6 is independently as defined above; and

m is from 1 to 20.

6. A compound as claimed in claim 5 which is:

a) a polyol ended binary co-oligomer of the formula (Ia):

H—[OR 2 O(O)C.C(HR 3 ).(HR 4 )C.C(O)] m —OR 2 O—H  (Ia)

where R 2 , R 3 , R 4 and m are as defined in formula (I); or

b) a fatty acid ester of the formula (Ib):

R 1 —[OR 2b O(O)C.C(HR 3 ).(HR 4 )C.C(O)] m —(OR 2b ) n —R 5b   (Ib)

where

each R 3 , R 4 and m is independently as defined in formula (I);

each R 1b and each R 5b is independently —H, or a group

each R 2b is independently a group R 2 as defined in formula (I), or such a group esterified with one or more groups —C(O)R 6 ; where each R 6 is independently as defined in formula (I);

n is 0 or 1;

such that the compound includes an average of at least 0.1, group —C(O)R 6 and an average of at least 1 OH group;

or a mixture of two or more of the compounds (Ia) or (Ib).

7. A compound as claimed in claim 5 wherein the group R 2 contains from 1 to 6 free hydroxyl groups.

8. A compound as claimed in claim 7 wherein the group R 2 is a group of the formula: —(CH 2 ) p1 (CHOH) p2 (CH 2 ) p3 — wherein p1 and p3 are each independently from 1 to 3, and p2 is from 1 to 6.

9. The compound of claim 5 , wherein the group R 3 is a group —(CH 2 ) n — where n is from 2 to 10.

10. The compound of claim 5 , wherein the index m is from 3 to 20.

11. A method of making a compound as claimed in claim 1 which comprises reacting an alkenyl succinic anhydride, acid or reactive derivative with a polyol having at least 3 free hydroxyl groups under esterification conditions.

12. An emulsion including a compound as claimed in claim 1 as an emulsifier.

13. An emulsion as claimed in claim 12 in the form of a oil in water personal care emulsion in which the disperse oil phase is an emollient oil or wax.

14. An emulsion as claimed in claim 13 in the form of a cream or a milk and including from 3 to 5% by weight of the emulsion of emulsifier and/or emulsion stabiliser.

15. A method of emulsion polymerisation in which an emulsion of one or more ethylenically unsaturated monomers in water emulsified with a compound as claimed in claim 1 is subjected to free radical polymerisation.

16. A dispersion of a solid in an aqueous medium including from 0.2 to 10% by weight of the solid of a compound as claimed in claim 1 .

17. A laundry detergent formulation including a compound as claimed in claim 1 .

18. An agrochemical formulation including a compound as claimed in claim 1 as an adjuvant, dispersant and/or emulsifier.

19. A foam drilling fluid including from 1 to 3% by weight of the drilling fluid of a compound as claimed in claim 1 as a foaming agent.

20. A method of inhibiting gas hydrate formation which comprises including in a water containing hydrocarbon stream subject to hydrate formation a compound as claimed in claim 1 as a gas hydrate inhibitor.

21. A water based drilling fluid including from 0.05 to 10% by weight of the drilling fluid of a compound as claimed in claim 1 as a lubricating agent.

22. A method of polymerising or copolymerising acrylamide in which acrylamide and any co-monomer(s), are dissolved in water, this solution is emulsified in oil, and the polymerisation initiated, in which a compound as claimed in claim 1 as an emulsifier.

23. A method as claimed in claim 22 wherein the amount of emulsifier used is from 2.5 to 7% by weight of the polymerisation emulsion.

24. A dispersion of a solid in a non-aqueous medium including from 0.5 to 7.5% by weight of the dispersion of a compound as claimed in claim 1 .

25. An emulsion explosive comprising an emulsion of an aqueous solution of an oxidiser salt in a liquid fuel including from 0.5 to 5% by weight based on the overall emulsion of a compound as claimed in claim 1 as an emulsifier.

26. A personal care emulsion or dispersion comprising a continuous phase of an emollient oil having dispersed therein a water based liquid, or a hydrophile phase and including a compound as claimed in claim 1 as an emulsifier and/or dispersant.

27. A dispersion as claimed in claim 26 which includes one or more sunscreen component.

28. A method of demulsifying a stream containing water emulsified in oil comprising adding to the stream from 1 to 500 ppm by weight of the oil stream of a compound as claimed in claim 1 as a demulsifier.

29. A metal working fluid including a compound as claimed in claim 1 as an emulsifier and/or lubricant.

30. A method of making an oligoester which comprises reacting a polyol (or a reactive derivative) with an alk(en)yl succinic anhydride, acid or reactive derivative, under esterification conditions to form an oligoester.