PROCESS FOR THE REDUCTION OF REGIOISOMER WHERE THE DOUBLE BOND IS SHIFTED FROM ETHYLENICALLY UNSATURATED ALKOXYLATED ALCOHOLS

Abstract

A process for the reduction of the content of a compound I of general formula (II)

##STR00001##

where R1 is hydrogen or methyl, each R2, independently from each other, is hydrogen or methyl, R3 is hydrogen or an aliphatic or cycloaliphatic or aromatic hydrocarbon with 1-8 carbon atoms, AO is a C2-C12 oxyalkylene group, x=0 or 1, and n=2-350, from a mixture including or consisting of a compound I of general formula (II) and an alkoxylated alcohol A of general formula (I)

##STR00002##

where R1, R2, R3, AO, x, and n are as described in general formula (II) above, characterized in that the process includes a treatment of the mixture including or consisting of a compound I and an alkoxylated alcohol A with an acid. Also, the use of the alkoxylated alcohols A for the production of polycarboxylate ethers.

Claims

1. A process for the reduction of the content of a compound I of general formula (II) ##STR00012## where R.sup.1 is hydrogen or methyl, each R.sup.2, independently from each other, is hydrogen or methyl, R.sup.3 is hydrogen or an aliphatic or cycloaliphatic or aromatic hydrocarbon with 1-8 carbon atoms, AO is a C2-C12 oxyalkylene group, x=0 or 1, and n=2-350, from a mixture comprising or consisting of a compound I of general formula (II) and an alkoxylated alcohol A of general formula (I) ##STR00013## where R.sup.1, R.sup.2, R.sup.3, AO, x, and n are as described in general formula (II) above, wherein the process comprises a treatment of the mixture comprising or consisting of a compound I and an alkoxylated alcohol A with an acid.

2. A process according to claim 1, wherein the mixture comprising a compound I of general formula (II) and an alkoxylated alcohol A of general formula (I) is a solution or a dispersion of a compound I of general formula (II) and an alkoxylated alcohol A of general formula (I) in a liquid.

3. A process according to claim 1, wherein R.sup.1 is methyl, R.sup.2 are hydrogen, R.sup.3 is hydrogen, AO is an oxyethylene group, x=0 or 1, and n=2-350.

4. A process according to claim 1, wherein the acid has a pKa value of not more than 4.5.

5. A process according to claim 1, wherein the acid is selected from the group consisting of hydrohalic acids, perchloric acid, chloric acid, iodic acid, sulfonic acids, nitric acid, nitrous acid, phosphoric acid, oxalic acid, chloroacetic acid, trifluoroacetic acid, citric acid, formic acid, lactic acid, ascorbic acid, benzoic acid, picric acid, maleic acid, and acrylic acid.

6. A process according to claim 1, wherein the acid treatment is carried out at a temperature of between 15-100° C. and a pressure of appr. 1013 mbar.

7. A process according to claim 1, wherein the content of a compound I of general formula (II) in a mixture comprising or consisting of a compound I of general formula (II) and an alkoxylated alcohol A of general formula (I) is reduced to not more than 10 wt. % relative to the total dry weight of the alkoxylated alcohol A of general formula (I).

8. A monomer mixture obtainable by a process according to claim 1.

9. A monomer mixture according to claim 8, wherein it comprises or essentially consists of an alkoxylated alcohol A of general formula (I) ##STR00014## where R.sup.1 is hydrogen or methyl, each R.sup.2, independently from each other, is hydrogen or methyl, R.sup.3 is hydrogen or an aliphatic or cycloaliphatic or aromatic hydrocarbon with 1-8 carbon atoms, AO is a C2-C12 oxyalkylene group, x=0 or 1, and n=2-350, and wherein the content of a compound I of general formula (II) ##STR00015## where R.sup.1, R.sup.2, R.sup.3, AO, x, and n are as described in general formula (I) above, is not more than 10 wt. % relative to the total dry weight of the alkoxylated alcohol A of general formula (I) in the monomer mixture.

10. A process for the production of polycarboxylate ether, comprising free radical polymerization of the monomer mixture of claim 8.

11. The process according to claim 10, wherein the monomer mixture is copolymerized with an ethylenically unsaturated carboxylic acid selected from maleic acid, acrylic acid, methacrylic acid, and mixtures thereof.

12. Copolymer obtained by a process of free radical polymerization of a monomer mixture according to claim 8 and at least one ethylenically unsaturated carboxylic acid selected from maleic acid, acrylic acid, methacrylic acid, and mixtures thereof.

13. A dispersant for mineral binders and/or mineral binder compositions comprising the copolymer of claim 12.

14. Mineral binder or mineral binder composition comprising a copolymer as claimed in claim 12.

Description

EXAMPLES

HPLC Measurements

[0074] HPLC measurements were done using a column MGII 100 ↑, 5 μm, 10 mm (I.D.)×250 mm manufactured by Shiseido Fine Chemicals. The eluent was a mixture of acetonitrile and water (45:55 by volume). The sample to be measured was a 10% solution in the eluent. 100 μL of sample were injected and the measurement was done at a flow rate of 1.0 mL/min at a column temperature of 40° C. The detector used was a Waters 2414 RI detector. The analysis software was Empower 2 by Waters Sampling. Generally, the compound I of general formula (II) has a higher retention time as compared to the alkoxylated alcohol A of the general formula (I).

[0075] The content of the compound I of general formula (II) can be calculated from the surface area ratio in the chromatogram by using the following equation:

c.sub.I=[SA.sub.I/(SA.sub.I+SA.sub.A)]*100

where c.sub.I=content of the compound I of general formula (II), SA.sub.I=surface area of the compound I of general formula (II), SA.sub.A=surface area of the alkoxylated alcohol A of the general formula (I).

Preparation of HPEG Solutions 1-5

[0076] Aqueous solutions of methallyl-started polyethyleneoxide (HPEG with molecular mass Mw=2400 g/mol) were prepared by dissolving 220 g of HPEG in 220 g of water. To these solutions was added aqueous HCl (1M) to adjust the pH to the values as indicated in the below table 1. The respective solutions were stirred for 12 h at 23° C. to yield HPEG solutions 1-5, and then HPLC measurements were performed as described above to determine the isomer content. In the HPLC chromatogram, the Isomethallyl-isomer of HPEG was visible at about 26.2 min retention time and the HPEG main isomer was visible at about 20.5 min. The isomer content of the HPEG solutions 1-5 are indicated in the below table 1.

[0077] The treated HPEG solutions 1, 1a, 1b, 1c, 1d, and 5 were subsequently used to prepare polymers P1, P1a, P1b, P1c, P1d, and P5. An aqueous solution of HPEG (50% solids content, Mw=2400 g/mol) without acid treatment (reference, not according to the invention, pH=7) was used to prepare reference polymer P.sub.ref.

Preparation of Polymers P1, P1a, P1b, P1c, P1d, P5, and P.SUB.ref

[0078] A glass reactor with a thermometer, a stirrer, a dropping funnel, and a reflux condenser was charged with 460 g of the respective aqueous HPEG solution 1, 1a, 1b, 1c, 1d, 5, or the reference prepared as described above. The pH of the respective solution was adjusted with 1M NaOH or 1M HCl to 4.5. Thereto, a mixture of 3 g hydrogen peroxide (35%) and 7 g water, a mixture of 34 g acrylic acid and 55 g water, and a mixture of 2 g of natriumhydroxymethansulfinate and 11 g of water were added in parallel over a period of 60 minutes. Thereafter, the temperature was raised to 65° C. and kept for 60 minutes to complete the polymerization reaction. Polymers P1, P1a, P1b, P1c, P1d, P5, and P.sub.ref were thus obtained in aqueous solution. P.sub.ref is not according to the present invention. The aqueous solutions of polymers P1, P1a, P1b, P1c, P1d, P5, and P.sub.ref were further diluted with water to a solid content of 20%.

Preparation of Mortar Mixtures 1, 1a, 1b, 1c, 1d, 5, and Reference

[0079] Mortar mixtures 1, 1a, 1b, 1c, 1d, 5, and Reference were prepared by mixing 750 g cement (CEM II A-LL 42.5 N from Vigier), 141 g limestone (Nekafill 15 from Kalkfabrik Netstal AG), and 3000 g aggregates (particle size 0-8 mm) in a dry state for 30 seconds in a Hobart mixer. 37.5 g of the respective aqueous solution of polymer P1, P1a, P1b, P1c, P1d, P5, and P.sub.ref as described above were added to the dry mix (the resulting w/c ratio was 0.42, the resulting dosage of the respective polymer was 1% by weight of cement). The mortar mixtures 1 and 5 correspond to examples 1 and 5 of below table 1 which are according to the present invention. The reference mortar mixture corresponds to the Reference in below table 1 which is not according to the present invention.

[0080] Slump flow of the respective mortar mixtures were measured according to EN 12350-5 after the times indicated in table 1.

TABLE-US-00001 TABLE 1 results of measurements Content of Slump flow of pH of HPEG- mortar mixture [mm] HPEG isomer 0 30 60 90 Example solution [mol %] min min min min 1 2.0 0 238 225 190 155  1a 1.95 0.005 235 226 193 156  1b 2.0 0.015 237 227 196 158  1c 2.0 0.1 236 227 192 156  1d 2.1 0.2 236 224 190 155 2 2.5 0.7 n.m. n.m. n.m. n.m. 3 3.0 2.2 n.m. n.m. n.m. n.m. 4 3.5 3.0 n.m. n.m. n.m. n.m. 5 4.5 4.8 225 216 189 159 Reference* 7 10.2 210 202 185 161 *the reference is the aqueous HPEG solution (50% solids content, Mw = 2400 g/mol) without any acid treatment n.m.: not measured

[0081] As can be seen from the above table 1 a reduced isomer content in the starting HPEG solution leads to an improved slump flow in a mortar mixture when polymers are used which are based on this HPEG solution. Especially, the initial slump flow is increased as the isomer content is reduced.