Use of substituted polyethyleneimines as gas hydrate inhibitors with improved biodegradability
The invention provides for the use of substituted polyethyleneimines containing structural units of the formula (1), where R1 is H, C 1 -C 30 -alkyl, C 1 -C 30 -alkenyl or C 7 -C 30 -alkylaryl R2, R3, R4, R5 are each independently H or C 1 -C 6 -alkyl, in amounts of from 0.01 to 2% by weight to prevent the formation of gas hydrates in aqueous phases which are in contact with a gaseous, liquid or solid organic phase.
1 . A process for the prevention of the formulation of gas hydrates in an aqueous phase, wherein the aqueous phase is in contact with a gaseous, liquid or solid organic phase comprising the step of contacting the gaseous, liquid or solid organic phase with at least one substituted polyethyleneimine containing repeat structural units of the formula (1),
wherein
R1 is H, C 1 -C 30 -alkyl, C 1 -C 30 -alkenyl or C 7 -C 30 -alkylaryl
R2, R3, R4, R5 are each independently H or C 1 -C 6 -alkyl,
in amounts of from 0.01 to 2% by weight.
2 . The process as claimed in claim 1 , wherein the least one substituted polyethyleneimine is a homopolymer containing repeat structural units of the formula 1.
3 . The process as claimed in claim 1 , wherein the molecular weight (M w ) of the at least one substituted polyethyleneimine is between 500 and 100000 g/mol.
4 . The process as claimed in claim 1 , wherein the at least one substituted polyethyleneimine is a copolymer containing at least 20 mol % of repeat structural units of the formula (1).
5 . The process as claimed in claim 1 , wherein the at least one substituted polyethyleneimine is a copolymer which, as well as structural units of the formula 1, comprises those of the formula 4
wherein
R6 is H, C 1 - to C 30 -alkyl, C 2 - to C 30 -alkenyl, C 6 -C 30 -aryl or C 7 to C 30 -alkylaryl
R7, R8, R9, R10 are each independently H or C 1 - to C 6 -alkyl.
6 . The process as claimed in claim 5 , wherein R6 is an ethyl group and R7, R8, R9, R10 are each hydrogen.
7 . The process as claimed in claim 1 , wherein the at least one substituted polyethyleneimine contains from 20 to 99 mol % of structural units of the formula 1.
8 . The process as claimed in claim 1 , wherein the at least one substituted polyethyleneimine contains from 1 to 80 mol % of structural units of the formula 4.
9 . A compound for the prevention of the formulation of gas hydrates in an aqueous phase comprising at least one substituted polyethyleneimine containing repeat structural units of the formula (1),
wherein
R1 is H, C 1 -C 30 -alkyl, C 1 -C 30 -alkenyl or C 7 -C 30 -alkylaryl; and
R2, R3, R4, R5 are each independently H or C 1 -C 6 -alkyl.