Stabilisers for use in inverse emulsion polymerisation processes
The present invention is directed to the use of a quaternized derivative of polyisobutylene as stabiliser in inverse emulsions like inverse emulsions used for a reverse-phase emulsion polymerisation process, e.g. for the polymerisation of acrylamide and ethylenically unsaturated cationic monomers. Such emulsions are e.g. used as flocculant for waste water treatment. The present invention is further directed to inverse emulsions comprising a quaternized derivative of polyisobutylene. The inverse emulsions have sufficiently low viscosity and sufficiently high shear stability. The present invention is further directed to an inverse emulsion polymerisation process, wherein the inverse emulsion comprises a quaternized derivative of polyisobutylene.
1. An inverse emulsion stabilizer comprising a quaternized derivative of polyisobutylene.
2. An inverse emulsion polymerization process, wherein the inverse emulsion comprises a reaction product of a quaternized derivative of polyisobutylene by
a) reacting a polyisobutylene-substituted acylating agent and a compound having a nitrogen atom capable of reacting with said acylating agent and further having a tertiary amino group; and
b) a quaternizing agent suitable for converting the tertiary amino group to a quaternary ammonium group;
wherein the reaction of the polyisobutylene-substituted acylating agent and the compound having a nitrogen atom capable of reacting with said acylating agent is a nucleophilic substitution reaction at an acyl group of the acylating agent resulting in a polyisobutylene-substituted amide or imide.
3. The polymerization process according to claim 2 , wherein the polyisobutylene-substituted acylating agent is the reaction product of a polyisobutylene and an acylating agent.
4. The polymerization process according to claim 3 , wherein the acylating agent is an alpha, beta-unsaturated mono- or polycarboxylic acid, polycarboxylic anhydride, mono- or polycarboxylic acid chloride, or mono- or polycarboxylic ester.
5. The polymerization process according to claim 2 , wherein the acylating agent is selected from the group consisting of acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, diethylester of fumaric acid, and mixtures thereof.
6. The polymerization process according to claim 2 , wherein the polyisobutylene has a number average molecular weight of 300 to 5000 g/mol.
7. The polymerization process according to claim 2 , wherein the polyisobutylene-substituted acylating agent comprises polyisobutylene succinic anhydride.
8. The polymerization process according to claim 7 , wherein the polyisobutylene moiety of the polyisobutylene-substituted acylating agent has a number average molecular weight of 300 to 5000 g/mol.
9. The polymerization process according to claim 2 , wherein in the compound having a nitrogen atom capable of reacting with the acylating agent and further having a tertiary amino group the nitrogen atom capable of reacting with the acylating agent and the tertiary amino group are linked by a direct covalent bond or by a linker group comprising between 1 and 6 carbon atoms.
10. The polymerization process according to claim 2 , wherein the compound having a nitrogen atom capable of reacting with the acylating agent and further having a tertiary amino group is selected from the group of N,N-dimethyl-1,3-diaminopropane, N,N-diethyl-1,3-diaminopropane, N,N-dibutyl-1,3-diaminopropane, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, 1-(3-aminopropyl) imidazole, 4-(3-aminopropyl) morpholine, 1-(2-aminoethyl) piperidine, 3,3′-diamino-N-methyldipropylamine, 3,3′-aminobis (N,N-dimethylpropylamine), 1-aminopiperidine, 1-(3-aminopropyl)-2-pipecoline, 1-methyl-(4-methylamino) piperidine, 4-(1-pyrrolidinyl) piperidine, 1-(2-aminoethyl) pyrrolidine, 2-(2-aminoethyl)-1-methylpyrrolidine, N,N,N′-trimethylethylenediamine, N,N-dimethyl-N′-ethylethylenediamine, N,N-diethyl-N′-methylethylenediamine, N,N,N′-triethylethylenediamine, N,N,N′-trimethyl-1,3-propanediamine, N,N,2,2-tetramethyl-1,3-propanediamine, 2-amino-5-diethylaminopentane, N,N,N′,N′-tetraethyldiethylenetriamine, 3,3′-diamino-N-methyldipropylamine, 3,3′-iminobis (N,N-dimethylpropylamine), and mixtures thereof.
11. The polymerization process according to claim 2 , wherein in the compound having a nitrogen atom capable of reacting with the acylating agent and further having a tertiary amino group the nitrogen atom capable of reacting with the acylating agent is part of a primary amino group.
12. The polymerization process according to claim 2 , wherein the quaternizing agent is selected from the group of ethylene oxide, propylene oxide, butylene oxide, styrene oxide, dialkyl sulfates, alkyl halides, benzyl halides, hydrocarbyl substituted carbonates, and mixtures thereof.
13. The polymerization process according to claim 2 , wherein the quaternary ammonium group comprises four groups attached to the nitrogen atom, wherein these groups are independently aliphatic or aromatic groups having from 1 to 6 carbon atoms.
14. The polymerization process according to claim 13 , wherein the groups attached to the nitrogen atom are independently alkyl or aryl groups having from 1 to 6 carbon atoms, optionally independently at least one of these groups carrying one or more hydroxyl groups.
15. The polymerization process according to claim 14 , wherein at least two of the groups attached to the nitrogen atom are identical.