Process for the reduction of regioisomers wherein the double bond is transferred from an olefinically unsaturated alkoxylated alcohol

Abstract

The invention relates to a method for reducing the content of a compound I of the general formula (II) from or from a mixture consisting of a compound I of the general formula (II) and an alkoxylated alcohol A of the general formula (I): wherein R 1 is hydrogen or methyl, each R 2 is independently of one another hydrogen or methyl, R 3 is hydrogen or an aliphatic or cycloaliphatic or aromatic hydrocarbon having 1 to 8 carbon atoms, AO is C2-C12oxyalkylene, x = 0 or 1, n = 2 to 350, wherein R 1 , R 2 , R 3 , AO, x and n are as described above in the general formula (II), characterized in that the method comprises treating the mixture comprising the compound I and the alkoxylated alcohol A or consisting of the compound I and the alkoxylated alcohol A with an acid. The invention also relates to the use of such alkoxylated alcohols A for the production of polycarboxylate ethers.

Description

Technical Field

[0001] This invention relates to a method for reducing the content of regioisomers in which double bonds are transferred in olefinically unsaturated alkoxylated alcohols. The invention also relates to the use of olefinically unsaturated alkoxylated alcohols having low contents of regioisomers in which double bonds are transferred for the production of polycarboxylate ethers. Background Technology

[0002] Dispersants are used in the construction industry as plasticizers or water-reducing agents in mineral binders and / or mineral binder compositions (e.g., concrete, mortar, cement, gypsum, and lime). Organic polymers are commonly used as dispersants. These organic polymers are added to the mixed water or as solids to the binder or binder composition. In this way, the consistency of the binder composition during processing and its properties in the cured state can be advantageously altered. The selection and dosage of a suitable dispersant depend particularly on the specific composition of the binder or binder composition, the processing techniques, and the intended use.

[0003] In practice, high-performance plasticizers in the form of polycarboxylate ethers (PCEs) are often used as dispersants in mineral binders or mineral binder compositions, for example, to improve the flow behavior of mineral binder compositions.

[0004] PCEs based on the alkoxylation of olefinic carboxylic acids and olefinic alcohols, particularly alkoxylated allyl alcohols, methyl allyl alcohols, and / or isoprenyl alcohols, are particularly useful in many respects. Such PCEs are described, for example, in EP1437330 (Nippon Shokubai).

[0005] EP 2152771 (Nippon Shokubai) and EP 2465836 (Nippon Shokubai) teach that in the case of increased content of double-bond-transferred regioisomers in the alkoxylation products of methyl allyl alcohol or isoprene alcohol, this does indeed reduce the plasticizing effect of copolymers prepared from acrylic acid and the corresponding alkoxylated alcohols in cement blends. In other words, for polycarboxylate ethers to have good plasticizing effects in cement blends, it is desirable to control and / or reduce the content of double-bond-transferred regioisomers constituting the monomers. EP 2152771 and EP 2465836 teach that lower reaction temperatures in the alkoxylation reaction of methyl allyl alcohol or isoprene alcohol will result in a reduction in the amount of the corresponding double-bond-transferred regioisomers. However, lower reaction temperatures are not always desirable, especially in cases requiring rapid reactions. Additionally, it may be desirable to further reduce the content of double-bond-transferred regioisomers in the alkoxylation products of olefinic alcohols after the alkoxylation reaction has terminated.

[0006] Therefore, there is a need for processes and methods to control and reduce the content of regioisomers in the alkoxylation products of olefinic unsaturated alcohols, in which double bonds are transferred. Such processes and methods are particularly needed when the corresponding alkoxylation products are intended to be used as monomers to produce polycarboxylate ethers. Summary of the Invention Invention Overview

[0008] One object of the present invention is to provide olefinically unsaturated alkoxylated alcohols, particularly alkoxylated methyl allyl alcohol or alkoxylated isoprene alcohol, having a low content of regioisomers in which double bonds are transferred.

[0009] Surprisingly, this objective can be achieved by the method according to claim 1.

[0010] The core of this invention is therefore a method for reducing the content of compound I of general formula (II) from a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I):

[0011]

[0012] Where R 1 For hydrogen or methyl, each R 2 Each can be either hydrogen or methyl, R 3 It is a hydrogen or an aliphatic, alicyclic, or aromatic hydrocarbon containing 1-8 carbon atoms, AO is a C2-C12 oxoalkylene, x = 0 or 1, and n = 2-350.

[0013]

[0014] Where R 1 R 2 R 3 AO, x, and n are as described in general formula (II) above, characterized in that the method comprises treating the mixture comprising compound I and alkoxylated alcohol A or a mixture of compound I and alkoxylated alcohol A with acid.

[0015] Alkoxylated alcohols of formula (I) with low contents of compound I of formula (II) (which correspond to the regioisomers of which double bonds are transferred) can be used as monomers for the preparation of polycarboxylate ethers (PCEs). Surprisingly, PCEs prepared from this monomer exhibit significantly higher initial slump flow compared to PCEs prepared from alkoxylated alcohols of formula (I) with higher contents of compound I of formula (II). In other words, the reduced content of compound I of formula (II) in the monomer mixture used to prepare the PCE results in higher initial slump flow in cement compositions containing this PCE.

[0016] Preferred embodiments of the invention are the subject of the dependent claims. Other aspects of the invention are the subject of the independent claims.

[0017] Method for implementing the present invention

[0018] In a first aspect, the present invention relates to a method for reducing the content of compound I of general formula (II) from a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I):

[0019]

[0020] Where R 1 For hydrogen or methyl, each R 2 Each can be either hydrogen or methyl, R 3 It is a hydrogen or an aliphatic, alicyclic, or aromatic hydrocarbon containing 1-8 carbon atoms, AO is a C2-C12 oxoalkylene, x = 0 or 1, and n = 2-350.

[0021]

[0022] Where R 1 R 2 R 3 AO, x, and n are as described in general formula (II) above, characterized in that the method comprises treating the mixture comprising compound I and alkoxylated alcohol A or a mixture of compound I and alkoxylated alcohol A with acid.

[0023] In this context, the term "reduction in the content of compound I" refers to a decrease in the content of compound I in the corresponding mixture after implementing the method of the present invention, compared to the content of compound I before implementing the method of the present invention. According to a preferred embodiment, the content of compound I of general formula (II) in a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is reduced to no more than 10% by weight, preferably no more than 5% by weight, more preferably no more than 1% by weight, even more preferably no more than 0.5% by weight, and especially no more than 0.1% by weight, in each case relative to the total dry weight of alkoxylated alcohol A of general formula (I).

[0024] The content of compound I of general formula (II) in a mixture containing compound I of general formula (II) and alkoxylated alcohol A of general formula (I) can be measured by HPLC. Any suitable HPLC method known to those skilled in the art can be used herein. A preferred HPLC procedure is as follows: Stationary phase: Column MGII 5 μm, 10 mm (ID) × 250 mm, manufactured by Shiseido Fine Chemicals; mobile phase: a mixture of acetonitrile and water (45:55 by volume); sample preparation: a 10% solution of the sample in the eluent; mode: injection of 100 μL of sample, measured at a flow rate of 1.0 mL / min at a column temperature of 40 °C; detector: Waters 2414RI detector; analysis software: Empower 2 from Waters.

[0025] Another method for measuring the content of compound I of general formula (II) in a mixture containing compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is... 1 H-NMR.

[0026] In this context, compound I of general formula (II) and alkoxylated alcohol A of general formula (I) are intended to cover their respective cis and trans isomers. This means that compound I and alkoxylated alcohol A contain double bonds in cis configuration or trans configuration or a mixture of cis and trans configurations.

[0027] According to the preferred embodiment, in equations (I) and (II) above, R 1 It is methyl, R 2 It is hydrogen, R 3The hydrogen atom is AO, which is oxyethylidene or oxypropylidene, x = 0 or 1, and n = 2-350. Therefore, alkoxylated alcohol A is preferably ethoxylated methylallyl alcohol, ethoxylated isoprene alcohol, propoxylated methylallyl alcohol, or propoxylated isoprene alcohol. Therefore, compound I is preferably ethoxylated isomethylallyl alcohol, ethoxylated isoprene alcohol, propoxylated isomethylallyl alcohol, or propoxylated isoprene alcohol.

[0028] The method of the present invention can be substantially implemented. That is, the method of the present invention can be a method of reducing the content of compound I of general formula (II) from a mixture consisting of compound I of general formula (II) and alkoxylated alcohol A of general formula (I), wherein the mixture is treated with acid. When the mixture consisting of compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is solid at room temperature, it is preferable to heat such solid to above its melting point or softening point to implement the method of the present invention. However, it is generally preferred that the method of the present invention be carried out in a solution or dispersion of the mixture of compound I of general formula (II) and alkoxylated alcohol A of general formula (I) in a liquid medium (preferably water). This allows for a particularly efficient reaction.

[0029] Therefore, according to a preferred embodiment, the method of the present invention is characterized in that the mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is a solution or dispersion of compound I of general formula (II) and alkoxylated alcohol A of general formula (I) in a liquid (preferably water).

[0030] According to the implementation scheme, the pKa value of the acid used in the method of the present invention is not greater than 4.5, preferably not greater than 2, and more preferably not greater than 0.

[0031] The acid can be an inorganic acid, an organic acid, or a mixture thereof. Preferably, the acid is a non-oxidizing acid. In particular, the acid can be selected from hydrohalic acids, preferably hydrochloric acid or hydrobromic acid, perchloric acid, chloric acid, iodic acid, sulfuric acid, sulfonic acid, preferably methanesulfonic acid or p-toluenesulfonic 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, acrylic acid, silicates, preferably H-zeolites. Particularly preferred acids are selected from hydrochloric acid, phosphoric acid, citric acid, and ascorbic acid.

[0032] According to the embodiments, the acid can be used in liquid form. The liquid form can be a pure acid in liquid form or an acid in a liquid, particularly a solution or dispersion in water. Preferred liquid forms of acids are aqueous solutions of hydrochloric acid, phosphoric acid, maleic acid, oxalic acid, formic acid, and acrylic acid. According to other embodiments, the acid can also be in solid form. Using solid acids can be advantageous because removing solid acids from mixtures comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is simple. The solid acid can be a pure acid that is solid under the reaction conditions of the method of the present invention. The solid acid can also be an acid attached to a solid support or adsorbed onto a solid support. Suitable solid support materials include polystyrene, polyethylene glycol, polyacrylate, cellulose, silica, glass, and sheet silicates. Preferred solid forms of acids are p-toluenesulfonic acid, citric acid, maleic acid, and H-zeolithenes on solid supports.

[0033] When the method of the present invention is carried out in a solution or dispersion of a mixture of compound I of general formula (II) and alkoxylated alcohol A of general formula (I) in water, the pH during acid treatment is preferably equal to or lower than 3.5, preferably 3.0, more preferably 2.5, and especially 2.0.

[0034] The method of the present invention can be carried out in any manner known to those skilled in the art. Generally, it is preferred to add an acid to a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I), or a mixture consisting of compound I of general formula (II) and alkoxylated alcohol A of general formula (I). The addition of the acid can be carried out by any conventional means. For example, the acid for treatment can be added to a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I), or a mixture consisting of compound I of general formula (II) and alkoxylated alcohol A of general formula (I), in a storage tank, container, or reaction vessel. The method of the present invention can be carried out with or without stirring. Preferably, the method of the present invention is carried out with stirring. Stirring refers to stirring the mixture comprising compound I of general formula (II) and alkoxylated alcohol A, or a mixture consisting of compound I of general formula (II) and alkoxylated alcohol A, during the reaction period defined before, during, and / or after the addition of the acid. There is no particular limitation on the duration of the acid treatment. According to embodiments, acid treatment is performed on a mixture comprising compound I of general formula (II) and alkoxylated alcohol A, or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A, for 5 minutes to 24 hours, preferably 10 minutes to 12 hours, and especially for a duration of 30 minutes to 6 hours. The acid treatment can be performed over a wide temperature range, particularly at elevated temperatures. However, it is preferred to perform the acid treatment on a mixture comprising compound I of general formula (II) and alkoxylated alcohol A, or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A, at a temperature of 15-100°C and a pressure of approximately 1013 mbar. Therefore, according to embodiments, the method of the present invention is characterized by acid treatment being carried out at a temperature of 15-100°C and a pressure of approximately 1013 mbar. Acid treatment can also be performed under reduced pressure.

[0035] The method of the present invention may consist of the following steps: treating with acid a compound I comprising general formula (II) and an alkoxylated alcohol A, or a mixture comprising compound I of general formula (II) and an alkoxylated alcohol A. However, the method of the present invention may also include additional steps. These additional steps may in particular be selected from one or more of the following:

[0036] (i) Alkoxylation of alcohols to obtain alkoxylated alcohols of general formula (I),

[0037] (ii) Melt the mixture consisting of compound I of general formula (II) and alkoxylated alcohol A of general formula (I),

[0038] (iii) Preparation of a solution or dispersion in a liquid, particularly in water, comprising a compound I of general formula (II) and an alkoxylated alcohol A of general formula (I), or a mixture thereof.

[0039] (iv) Neutralize the acid.

[0040] Therefore, according to a preferred embodiment, the method of the present invention is characterized by comprising or consisting of the following steps:

[0041] (i) Alkoxylation of alcohols is optional to obtain alkoxylated alcohols of general formula (I).

[0042] (ii) Not necessarily, melt the mixture consisting of compound I of general formula (II) and alkoxylated alcohol A of general formula (I).

[0043] (iii) Not necessarily, preparing a solution or dispersion in a liquid, especially in water, comprising a compound I of general formula (II) and an alkoxylated alcohol A of general formula (I), or a mixture thereof.

[0044] (iv) Treat with acid a compound I comprising general formula (II) and alkoxylated alcohol A, or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A.

[0045] (v) Neutralize the acid if not necessary.

[0046] A particularly preferred method of the present invention comprises the following steps:

[0047] (i) Alkoxylation of alcohols to obtain alkoxylated alcohols of general formula (I),

[0048] (ii) Preparing a solution or dispersion in a liquid, particularly in water, comprising a compound I of general formula (II) and an alkoxylated alcohol A of general formula (I), or a mixture thereof.

[0049] (iii) Treating with acid a compound I comprising general formula (II) and alkoxylated alcohol A, or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A, and

[0050] (iv) Neutralize the acid if not necessary.

[0051] All the features described above that are preferred in the treatment of a mixture comprising compound I of general formula (II) and alkoxylated alcohol A or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A should also be understood as preferred features of the method comprising steps (i)-(v) as described above or preferred features of the method comprising steps (i)-(v) as described above.

[0052] In a second aspect, the present invention relates to monomer mixtures that can be obtained by the above-described method, particularly monomer mixtures for the production of polycarboxylate ethers (PCE).

[0053] In particular, in the monomer mixture of the present invention, the content of compound I of general formula (II) is not more than 10% by weight, preferably not more than 5% by weight, more preferably not more than 1% by weight, even more preferably not more than 0.5% by weight, especially not more than 0.01% by weight, especially less than 0.01% by weight, in each case relative to the total dry weight of alkoxylated alcohol A of general formula (I) in the monomer mixture.

[0054] In addition to compound I of general formula (II) and alkoxylated alcohol A of general formula (I) as described above, the monomer mixtures of the present invention may also contain other monomers. Such other monomers are in particular carboxylic acids containing olefinic unsaturated bonds. These olefinic unsaturated carboxylic acids are preferably selected from acrylic acid, methacrylic acid, maleic acid, and mixtures thereof. Alternatively, the monomer mixtures of the present invention may also contain monomers selected from alkyl and hydroxyalkyl esters of olefinic unsaturated carboxylic acids, amides of acrylic acid or methacrylic acid, styrene and its derivatives, vinyl alcohols, vinylpyrrolidone, and mixtures thereof. Therefore, the monomer mixtures of the present invention comprise or consist of: compound I of general formula (II), alkoxylated alcohol A of general formula (I), a monomer of at least one olefinic unsaturated carboxylic acid (preferably acrylic acid, methacrylic acid, and / or maleic acid), and, alternatively, other monomers selected from alkyl and hydroxyalkyl esters of olefinic unsaturated carboxylic acids, amides of acrylic acid or methacrylic acid, styrene and its derivatives, vinyl alcohols, and / or vinylpyrrolidone.

[0055] According to the embodiments, the monomer mixture of the present invention therefore comprises or is substantially composed of alkoxylated alcohol A of general formula (I):

[0056]

[0057] Where R 1 For hydrogen or methyl, each R 2 Each can be either hydrogen or methyl, R 3 It is a hydrogen or an aliphatic, alicyclic, or aromatic hydrocarbon containing 1-8 carbon atoms, AO is a C2-C12 oxoalkylene, x = 0 or 1, and n = 2-350.

[0058] The content of compound I of general formula (II) is not greater than 10% by weight, preferably not greater than 5% by weight, more preferably not greater than 1% by weight, even more preferably not greater than 0.5% by weight, especially not greater than 0.01% by weight, particularly less than 0.01% by weight, in each case relative to the total dry weight of alkoxylated alcohol A of general formula (I) in the monomer mixture.

[0059]

[0060] Where R 1 R 2 R 3 AO, x, and n are as described in general formula (I) above.

[0061] The monomer mixtures of the present invention may additionally comprise alkoxylated alcohols of general formula (V):

[0062]

[0063] Where R 3 AO and n are as described in general formula (II) above.

[0064] In a third aspect, the present invention relates to the use of the monomer mixtures described above for the production of polycarboxylate ethers (PCEs) by free radical polymerization. Suitable conditions for the production of PCEs by free radical polymerization are known to those skilled in the art and are described, for example, in EP 1437330 (Examples 1-1 to 3-3) or EP 1103570 (Examples 1-1 to 1-13).

[0065] In a particularly preferred embodiment of the invention, the monomer mixture described above is copolymerized with an olefinic unsaturated carboxylic acid selected from maleic acid, acrylic acid, methacrylic acid, and mixtures thereof.

[0066] According to the embodiments, maleic acid and acrylic acid can be used as acids for treating a mixture of compound I of general formula (II) and alkoxylated alcohol A of general formula (I) to reduce the content of compound I, and as monomers for the production of PCE. However, it is preferred that the olefinic unsaturated carboxylic acids selected from maleic acid, acrylic acid, methacrylic acid, and mixtures thereof are different from the acids used for treating a mixture of compound I of general formula (II) and alkoxylated alcohol A of general formula (I) to reduce the content of compound I.

[0067] According to a fourth aspect, the present invention relates to copolymers obtained by a free radical polymerization method of a monomer mixture as described above and at least one olefinic unsaturated carboxylic acid selected from maleic acid, acrylic acid, methacrylic acid, and mixtures thereof.

[0068] Such copolymers contain or are essentially composed of the following:

[0069] a) Repeating unit M-1 of general formula (III):

[0070]

[0071] and

[0072] b) Repeating unit M-2 of general formula (IV):

[0073]

[0074] Each R v Each is independently hydrogen or COOM, where M is hydrogen, an alkali metal, or an alkaline earth metal, and each R 1 and R u Each of them is independently hydrogen or methyl, each R 2 Each can be either hydrogen or methyl, R 3 It is hydrogen or an aliphatic, alicyclic, or aromatic hydrocarbon containing 1-8 carbon atoms; AO is a C2-C12 oxoalkylene group.

[0075] x = 0 or 1, and

[0076] n = 2 - 350,

[0077] The molar ratio of repeating unit M1 to repeating unit M-2 in the copolymer is 90:10-10:90.

[0078] Repeating units M-1 and / or M-2 can be arranged randomly, statistically, or in a block manner, or in a mixture of random and block manner, for example, in a gradient-wise manner along the main chain of the copolymer.

[0079] According to a fifth aspect, the present invention relates to the use of the copolymers described above as dispersants for mineral binders and / or mineral binder compositions.

[0080] In the context of this invention, a "mineral binder composition" is a composition comprising at least one mineral binder. The term "mineral binder" specifically refers to a binder that reacts in the presence of water during a hydration reaction to form a solid hydrate or hydrate phase. This can be a hydraulic binder (e.g., cement or mineral lime) or a non-hydraulic binder (e.g., white lime).

[0081] Examples of mineral binders are cements, such as Portland cement, blended cement, calcium aluminate cement, calcium sulfoaluminate cements, and gypsum and / or lime.

[0082] In particular, the mineral binder or binder composition contains a hydraulic binder, especially cement. The cement is preferably selected from at least one of CEM I, II, III, IV or V (according to standard EN 197-1), calcium aluminate cement (according to standard EN 14647:2006-01), and calcium sulfoaluminate (CSA) cement. Of course, cement produced according to relevant alternative standards (e.g., relevant ASTM or Chinese standards) is equally suitable.

[0083] It may also be advantageous if the mineral binder or mineral binder composition contains other binders besides or in place of hydraulic binders. These are particularly potential hydraulic binders and / or pozzolanic binders. Calcium sulfate may be added in small amounts to the mineral binder compositions of the present invention to compensate for sulfate loss during hydration. Small amounts refer to 0.1-5% by weight, preferably 0.1-1.5% by weight, of calcium sulfate based on the total weight of the mineral binder.

[0084] Gypsum refers to calcium sulfate dihydrate, α- and β-hemihydrate calcium sulfate and / or anhydrite.

[0085] Lime is any material as described in standard EN 459-1:2015.

[0086] In addition to mineral binders, mineral binder compositions typically contain inert materials such as aggregates, especially gravel and / or sand, and / or fillers such as limestone or quartz powder. Water may also be present.

[0087] In a final aspect, the present invention relates to mineral binders or mineral binder compositions comprising the copolymers described above. Specifically, the mineral binders or mineral binder compositions are as described above.

[0088] The following examples are illustrative and will provide additional information for those skilled in the art to implement the invention. They are not intended to limit the invention in any way. Example

[0089] HPLC measurement

[0090] Using column MGII manufactured by Shiseido Fine Chemicals HPLC measurements were performed at a column diameter of 5 μm, 10 mm (ID) × 250 mm. 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 was injected, and the measurement was performed at a column temperature of 40 °C and a flow rate of 1.0 mL / min. The detector used was a Waters 2414RI detector. The analytical software was Empower 2 from Waters Sampling. Generally, compound I of general formula (II) has a higher retention time compared to alkoxylated alcohol A of general formula (I).

[0091] The content of compound I of general formula (II) can be calculated from the surface area ratio in the chromatogram using the following formula:

[0092] c I =[SA I / (SA I +SA A )]*100

[0093] Where c I = The content of compound I of general formula (II), SA I = Surface area of ​​compound I of general formula (II), SA A = Surface area of ​​alkoxylated alcohol A of general formula (I).

[0094] Preparation of HPEG solutions 1-5

[0095] Aqueous solutions of methylallyl-based polyethylene oxide (HPEG with a molecular weight Mw = 2400 g / mol) were prepared by dissolving 220 g of HPEG in 220 g of water. HCl aqueous solution (1 M) was added to these solutions to adjust the pH to the values ​​shown in Table 1 below. Each solution was stirred at 23 °C for 12 hours to obtain HPEG solutions 1-5, which were then subjected to HPLC measurements as described above to determine the isomer content. In the HPLC chromatograms, the isomethylallyl isomer of HPEG was visible at a retention time of approximately 26.2 min, and the major isomer of HPEG was visible at approximately 20.5 min. The isomer contents of HPEG solutions 1-5 are shown in Table 1 below.

[0096] Subsequently, polymers P1, P1a, P1b, P1c, P1d, and P5 were prepared using treated HPEG solutions 1, 1a, 1b, 1c, 1d, and 5. Reference polymer P was prepared using an untreated aqueous solution of HPEG (50% solids content, Mw = 2400 g / mol) (reference, not according to the invention, pH = 7). ref .

[0097] Polymers P1, P1a, P1b, P1c, P1d, P5 and P ref Preparation

[0098] Add 460 g of the corresponding HPEG aqueous solutions 1, 1a, 1b, 1c, 1d, 5, or the reference prepared as described above to a glass reactor equipped with a thermometer, stirrer, dropping funnel, and reflux condenser. Adjust the pH of the corresponding solutions to 4.5 with 1M NaOH or 1M HCl. Over 60 minutes, add in parallel a mixture of 3 g of hydrogen peroxide (35%) and 7 g of water, a mixture of 34 g of acrylic acid and 55 g of water, and a mixture of 2 g of sodium hydroxymethanesulfinate and 11 g of water. Then, raise the temperature to 65°C and maintain it for 60 minutes to complete the polymerization reaction. Polymers P1, P1a, P1b, P1c, P1d, P5, and P6 are thus obtained in aqueous solution. ref P ref Not according to the present invention. Polymers P1, P1a, P1b, P1c, P1d, P5 and P... ref The aqueous solution was further diluted with water to a solid content of 20%.

[0099] Preparation of mortar mixtures 1, 1a, 1b, 1c, 1d, 5 and the reference material

[0100] Mortar mixtures 1, 1a, 1b, 1c, 1d, 5, and the reference were prepared by mixing 750g of cement (CEM II A-LL 42.5N from Vigier), 141g of limestone (Nekafill 15 from Kalkfabrik Netstal AG), and 3000g of aggregate (0-8mm particle size) in a Hobart mixer in a dry state for 30 seconds. 37.5g of polymers P1, P1a, P1b, P1c, P1d, P5, and P as described above were also prepared. ref The corresponding aqueous solution was added to the dry mixture (resulting in a w / c ratio of 0.42, and the resulting dosage of the corresponding polymer being 1% by weight of the cement). Mortar mixtures 1 and 5 correspond to Examples 1 and 5 of Table 1 below according to the invention. The reference mortar mixtures correspond to those in Table 1 below that are not according to the invention.

[0101] After the times shown in Table 1, the slump flow of each mortar mixture was measured according to EN 12350-5.

[0102] Table 1: Measurement Results

[0103]

[0104] *The reference material is an aqueous solution of HPEG without any acid treatment (50% solids content, Mw = 2400 g / mol).

[0105] nm: Not measured

[0106] As can be seen from Table 1 above, when using polymers based on this HPEG solution, the reduced isomer content in the initial HPEG solution leads to improved slump flow in the mortar mixture. In particular, the initial slump flow increases with decreasing isomer content.

Claims

1. A method for reducing the content of compound I of general formula (II) from a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I): (II) Where R 1 For hydrogen or methyl, each R 2 Each can be either hydrogen or methyl, R 3 It is hydrogen or an aliphatic, alicyclic, or aromatic hydrocarbon containing 1-8 carbon atoms; AO is a C2-C12 oxoalkylene group. x = 0 or 1, and n = 2-350， (I) Where R 1 R 2 R 3 AO, x, and n are defined in the same way as in general formula (II) above, characterized in that The method includes treating the mixture comprising compound I and alkoxylated alcohol A, or a mixture of compound I and alkoxylated alcohol A, with acid.

2. The method according to claim 1, characterized in that... A mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is a solution or dispersion of compound I of general formula (II) and alkoxylated alcohol A of general formula (I) in a liquid.

3. The method according to claim 2, characterized in that... The mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is a solution or dispersion of compound I of general formula (II) and alkoxylated alcohol A of general formula (I) in water.

4. The method according to any one of claims 1-3, characterized in that... R 1 It is methyl, R 2 It is hydrogen, R 3 It is hydrogen, AO is oxyethylidene, x=0 or 1, and n=2-350.

5. The method according to any one of claims 1-3, characterized in that... The acid has a pKa value of no more than 4.

5.

6. The method according to claim 5, characterized in that... The acid has a pKa value of no more than 2.

7. The method according to claim 5, characterized in that... The acid has a pKa value not greater than 0.

8. The method according to any one of claims 1-3, characterized in that... The acid is selected from hydrohalic acid, perchloric acid, chloric acid, iodic acid, sulfonic acid, 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.

9. The method according to claim 8, characterized in that... The hydrohalic acid is hydrochloric acid or hydrobromic acid.

10. The method according to claim 8, characterized in that... The sulfonic acid is methanesulfonic acid or p-toluenesulfonic acid.

11. The method according to any one of claims 1-3, characterized in that... The acid treatment was carried out at a temperature of 15-100°C and a pressure of 1013 mbar.

12. The method according to any one of claims 1-3, characterized in that... The content of compound I of general formula (II) in a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is reduced to no more than 10% by weight, in each case relative to the total dry weight of alkoxylated alcohol A of general formula (I).

13. The method according to claim 12, characterized in that... The content of compound I of general formula (II) in a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is reduced to no more than 5% by weight, in each case relative to the total dry weight of alkoxylated alcohol A of general formula (I).

14. The method according to claim 12, characterized in that... The content of compound I of general formula (II) in a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is reduced to no more than 1% by weight, in each case relative to the total dry weight of alkoxylated alcohol A of general formula (I).

15. The method according to claim 12, characterized in that... The content of compound I of general formula (II) in a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is reduced to no more than 0.5% by weight, in each case relative to the total dry weight of alkoxylated alcohol A of general formula (I).

16. The method according to claim 12, characterized in that... The content of compound I of general formula (II) in a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) or a mixture comprising compound I of general formula (II) and alkoxylated alcohol A of general formula (I) is reduced to no more than 0.1% by weight, in each case relative to the total dry weight of alkoxylated alcohol A of general formula (I).

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