JP2019500362A - Process for producing hydroxybenzophenone polyglycol ether (meth) acrylate - Google Patents

Abstract

  (I) a step of reacting hydroxybenzophenone with ethylene carbonate to give hydroxybenzophenone monoglycol ether, (ii) a step of ethoxylating hydroxybenzophenone monoglycol ether with ethylene oxide to give hydroxybenzophenone polyglycol ether, hydroxybenzophenone poly A process for producing hydroxybenzophenone polyglycol ether (meth) acrylate, comprising a step of transesterifying glycol ether and alkyl (meth) acrylate to form hydroxybenzophenone polyglycol ether (meth) acrylate.

Description

  The present invention relates to a method for producing hydroxybenzophenone polyglycol ether (meth) acrylate.

  Hydroxybenzophenone (meth) acrylate is used, for example, as a UV crosslinker in coating compositions. Hydroxybenzophenone (meth) acrylate can be produced by (meth) acrylate conversion of hydroxybenzophenone.

  By introducing a polyethylene glycol chain between the benzophenone unit and the (meth) acrylate group, a water-soluble product can be obtained. However, when the hydroxybenzophenone is directly alkoxylated and subsequently (meth) acrylated to the formed hydroxybenzophenone polyglycol ether, it is not further (meth) acrylated and in the coating composition. In this application, dimers and trimers of hydroxybenzophenone, such as polyethylene glycol bisbenzophenone, which can later migrate from the coating matrix are produced. On the other hand, polyethylene glycol is formed which can form di (meth) acrylate in methacrylated. This already acts as a crosslinker without UV activation, resulting in a gel-like water-insoluble product.

  From WO 00/15629 (WO 00/15629) it is known to react hydroxybenzophenone with activated polyethylene glycol to a hydroxybenzophenone polyglycol ether. Alkoxylated toluenesulfonic acid (polyethylene glycol monotosylate) is used as the activated polyethylene glycol. However, this type of manufacturing is very time consuming.

  The object of the present invention is to provide a process for the production of hydroxybenzophenone polyglycol ether (meth) acrylates which can be carried out simply, resulting in a highly pure product.

This task
(I) a step of reacting hydroxybenzophenone with ethylene carbonate to form hydroxybenzophenone monoglycol ether;
(Ii) a step of ethoxylating hydroxybenzophenone monoglycol ether with ethylene oxide to form hydroxybenzophenone polyglycol ether;
(Iii) A method for producing hydroxybenzophenone polyglycol ether (meth) acrylate, comprising transesterifying hydroxybenzophenone polyglycol ether and alkyl (meth) acrylate to form hydroxybenzophenone polyglycol ether (meth) acrylate Is done.

When hydroxybenzophenone is directly ethoxylated with ethylene oxide, in the first step, an aromatic alcoholate is produced and reacted with ethylene oxide using a base, such as KOH. The newly formed aliphatic alcoholate reacts further. As a side reaction, aromatic alcoholates can attack the ethoxylates of hydroxybenzophenone that have been formed, breaking the polyethylene glycol chain. The products are polyethylene glycol bisbenzophenone and polyethylene glycol.

  By tautomerization, ethoxylation of the enolate may occur as a further side reaction, which leads to trimers and higher homologues through subsequent reactions. This reaction results in the loss of photocrosslinkable units.

  These products were detected by mass spectrometry (binding LC-MS).

  Surprisingly, it has been found that the introduction of ethylene oxide groups by reaction with ethylene carbonate prior to ethoxylation with ethylene oxide avoids the formation of hydroxybenzophenone dimers and trimers, and polyethylene glycol.

  In general, the hydroxybenzophenones are 4-hydroxybenzophenone and 2-hydroxybenzophenone, preferably 4-hydroxybenzophenone.

  In the first step (i), hydroxybenzophenone and ethylene carbonate are reacted to form hydroxybenzophenone monoglycol ether.

  In general, this reaction is carried out in the presence of sodium iodide as a catalyst, as described, for example, in WO 2011/089385 (WO2011 / 089385).

  This reaction can be carried out in the presence of a separate solvent, such as toluene. This reaction can be carried out without a separate solvent. In general, the reaction is carried out at a temperature in the range of 100 to 200 ° C, preferably 120 to 180 ° C. In this case, ethylene carbonate is preferably used in a slight stoichiometric excess. After completion of the reaction, water is added to the formed monoethoxylate, and hydroxybenzophenone monoglycol ether is extracted with an organic solvent such as toluene.

  In the second step (ii), the hydroxybenzophenone monoglycol ether is ethoxylated with ethylene oxide to give a hydroxybenzophenone polyglycol ether. In general, 2 to 100 mol, preferably 2 to 50 mol, particularly preferably 4 to 50 mol of ethylene oxide reacts per mol of hydroxybenzophenone monoglycol ether.

  Ethoxylation can be carried out with gaseous ethylene oxide in the presence of a basic catalyst, generally at a pressure of 1 to 10 bar and a temperature of 80 to 200 ° C. Suitable basic catalysts are, for example, NaOH, KOH, sodium or potassium methylate, or potassium-tert-butanolate. Potassium-tert-butanolate is preferred.

  In the third step (iii), the hydroxybenzophenone polyglycol ether and the alkyl (meth) acrylate are transesterified into a hydroxybenzophenone polyglycol ether (meth) acrylate.

In general, the transesterification is carried out in steps (iii-a) to (iii-d):
(Iii-a) Presence of an azeotropic agent that forms an azeotrope with an alkyl (meth) acrylate and hydroxybenzophenone polyglycol ether in the presence of a catalyst and a stabilizer, and an alcohol bonded in the alkyl (meth) acrylate. Reacting under,
(Iii-b) a step of continuously distilling off the azeotrope from the azeotropic agent and the alcohol, wherein steps (ii) and (iii) are carried out until the hydroxybenzophenone polyglycol ether is substantially completely reacted. Carried out at the same time,
(Iii-c) separating the catalyst from the hydroxybenzophenone polyglycol ether (meth) acrylate containing product mixture;
(Iii-d) distilling off unreacted alkyl (meth) acrylate and azeotropic agent from the product mixture.

  In step (iii-a), an azeotrope that forms an azeotrope between an alkyl (meth) acrylate and a hydroxybenzophenone polyglycol ether in the presence of a catalyst and a stabilizer and an alcohol bonded in the alkyl (meth) acrylate. The reaction is carried out in the presence of an agent, wherein simultaneously in step (iii-b) the azeotrope from the azeotropic agent and the alcohol is distilled off until the hydroxybenzophenone polyglycol ether is substantially completely reacted. That is, transesterification consists of steps (iii-a) and (iii-b).

Suitable alkyl (meth) acrylate _is a C 1 -C ₄ alkyl (meth) acrylate. In general, methyl (meth) acrylate or ethyl (meth) acrylate is used, where methanol or ethanol is released as alcohol in the transesterification reaction.

  The reaction between the alkyl (meth) acrylate and the hydroxybenzophenone polyglycol ether is carried out in the presence of a homogeneous catalyst or a heterogeneous catalyst. Catalysts and inorganic salts containing Lewis acids or Lewis bases suitable for transesterification such as tin, titanium or zirconium are all suitable.

Suitable tin-containing catalysts are Sn (IV) -containing compounds such as dialkyltin dichloride, dialkyltin oxide, dialkyltin diacetate, bis (trialkyltin) oxide, bis (dibutylchlorotin) oxide, in particular dibutyltin dichloride, dimethyl Tin dichloride and dibutyltin oxide. The chloride-containing catalyst can be used in combination with an alcoholate, such as sodium methylate. Catalysts containing suitable titanium (IV) or zirconium (IV) (collectively referred to herein as metal (IV)) are linear or branched C ₁ -C ₆ alcohol metal (IV) tetraalkoxylates. , Preferably metal (IV) tetraisopropylate, metal (IV) tetrabutyrate, and the metalate of the starting alcohol used or mixtures thereof. Metalates substituted with various alcohols or acetylacetonates are also possible.

Inorganic salts include carbonate ions (CO ₃ ²⁻ ), oxide ions (O ²⁻ ), hydroxide ions (OH ⁻ ), bicarbonate ions (HCO ₃ ⁻ ), phosphate ions (PO ₄ ³⁻ ), Hydrogen phosphate ion (HPO ₄ ²⁻ ), dihydrogen phosphate ion (H ₂ PO ₄ ⁻ ), nitrate ion (NO ₃ ⁻ ), sulfate ion (SO ₄ ²⁻ ), sulfite ion (SO ₃ ²⁻ ) and It is preferable to have at least one anion selected from the group consisting of carboxylate ions (R ⁶ COO ⁻ ) (where R ⁶ means C ₁ -C ₄ alkyl or C ₆ aryl). Oxide ions, hydroxide ions and phosphate ions or mixtures thereof are preferred, and phosphate ions are particularly preferred. The inorganic salt is at least one selected from the group consisting of alkali metal ions, alkaline earth metal ions, ammonium ions, cerium ions, iron ions, manganese ions, chromium ions, molybdenum ions, cobalt ions, nickel ions or zinc ions. It is preferable to have a cation. Alkali metal ions and alkaline earth metal ions are preferred, with lithium ions, sodium ions, potassium ions or calcium ions being particularly preferred. Particularly preferred inorganic salts (including hydrates thereof) are LiOH, LiNO ₃ , Li ₃ PO ₄ , Na ₃ PO ₄ , K ₃ PO ₄ , Na ₂ CO ₃ , K ₂ CO ₃ and CaO, and K ₃ PO ₄ is very particularly preferred.

  For example, in the transesterification method described in German Patent Application No. 2317226 (DE2317226A1), German Patent Application Publication No. 102004036930 (DE102004036930A1) and International Publication No. 2009/080380 (WO2009 / 080380). As used, heterogeneous catalysts or homogeneous catalysts that can be made into heterogeneous residues are particularly suitable. Basically, the catalyst or catalyst residue is separated by filtration, electrofiltration, adsorption, centrifugation or decanting.

  Furthermore, the reaction of alkyl (meth) acrylate and hydroxybenzophenone polyglycol ether is performed in the presence of one or more stabilizers (polymerization inhibitors). Hydroquinone, hydroquinone monomethyl ether, phenothiazine, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-N-oxyl, 2- tert-butylphenol, 4-tert-butylphenol, 2,4-di-tert-butylphenol, 2-tert-butyl-4-methylphenol, 6-tert-butyl-2,4-dimethylphenol, 2,6-di- Tert-butyl-4-methylphenol and 2-methyl-4-tert-butylphenol are preferred. Hydroquinone monomethyl ether (MeHQ) is particularly preferred.

  Advantageously, oxygen can additionally be used as a polymerization inhibitor.

  For further stabilization, an oxygen-containing gas, preferably air, or a mixture from air and nitrogen (lean air) can be present.

  In general, the transesterification reaction (steps (iii-a) and (iii-b)) is carried out at a temperature of 60 to 140 ° C, preferably 70 to 110 ° C. Here, the azeotropic agent and the azeotrope from the alcohol are continuously distilled off.

  Suitable azeotropic agents that form an azeotrope with methanol or ethanol are first methyl acrylate and methyl methacrylate, and ethyl acrylate and ethyl methacrylate itself. As separate azeotropic agents, cyclohexane, methylcyclohexane, benzene, toluene, hexane and heptane, and mixtures thereof are particularly suitable. Methyl acrylate, methyl methacrylate, ethyl acrylate and ethyl methacrylate, and mixtures thereof with n-heptane and cyclohexane are preferred. In this sense, the term azeotropic agent includes the starting material itself, and optionally also a separate solvent used.

  In a preferred embodiment, a separate solvent is not used as an azeotropic agent. In this case, the starting alkyl (meth) acrylate itself functions as an azeotropic agent.

  Subsequently, the reactor can be refilled with the azeotropic agent. To that end, in a preferred embodiment, the azeotrope from the alcohol and azeotropic agent is distilled off with a suitable column, stirred with water in a mixing vessel and then transferred to a phase separator, where the alcohol, generally In methanol or ethanol dissolves in water, the organic phase separates as the upper layer. The organic phase is preferably fed back into the reaction mixture via the top of the column and is therefore sent cyclically with a small loss. Alternatively, however, a new azeotropic agent can be added and the post-treatment of the azeotropic agent / alcohol mixture can be carried out in a separate step, or the replenishment of the azeotropic agent can be omitted completely or partially. it can.

  In general, the alkyl (meth) acrylate is used in stoichiometric excess. The excess methyl (meth) acrylate is preferably 5 to 2500 mol%, particularly preferably 300 to 2000 mol%, per hydroxyl group to be esterified.

  The catalyst is used in a concentration of 0.1 to 10 mol%, preferably 0.1 to 5 mol%, based on the amount of hydroxybenzophenone polyglycol ether.

  The transesterification can be carried out at atmospheric pressure, positive pressure or negative pressure. In general, the transesterification is carried out at 300 to 1000 mbar, preferably 300 to 700 mbar (atmospheric pressure = 1000 mbar). In general, the reaction time is 1 to 24 hours, preferably 3 to 18 hours, particularly preferably 3 to 10 hours. The transesterification (steps (iii-a) and (iii-b)) can be carried out continuously, for example in a stirred tank cascade or can be carried out discontinuously.

  This reaction can be carried out in any reactor suitable for such a reaction. Such reactors are known to those skilled in the art. This reaction is preferably carried out in a stirred kettle reactor.

  Any device, such as an agitation device, can be used to mix the batch. This mixing can be done by feeding a gas, preferably an oxygen-containing gas.

  Removal of the alcohol formed, generally methanol or ethanol, is carried out by azeotropic distillation in a manner known per se, continuously or stepwise, in the presence of an azeotropic agent. Furthermore, methanol can also be removed by stripping with gas.

  In a preferred embodiment, the alcohol is separated from the azeotropic agent distilled off in step (iii-b) and the azeotrope from the alcohol by washing with water, and the azeotropic agent is returned to the reaction vessel.

  Steps (iii-a) and (iii-b) are carried out until the hydroxybenzophenone polyglycol ether used has reacted substantially completely. This is the case when the hydroxybenzophenone polyglycol ether has reacted 95%, preferably 97%, particularly preferably 98%. The degree of conversion can be analyzed most simply by specifying the hydroxyl value. The hydroxyl value indicates the hydroxyl content as a total parameter in units of mg KOH / g substance, and can be converted to weight percent assuming a specific molar mass of alcohol.

  In step (iii-c), the catalyst is separated from the hydroxybenzophenone polyglycol ether (meth) acrylate containing product mixture, for example by filtration or centrifugation.

  Filtration can be performed using, for example, a pressure filtration Nutsche. Methodologically, any filtration method and apparatus known per se, such as Ullmann's Encyclopedia of Industrial Chemistry, 7th edition, 2013 electronic edition, chapter: Filtration, 1 . Fundamentals and Filtration Those described in Equipment can be used. These can be, for example, cartridge filters, filter presses, pressure plate filters, bag filters or drum filters. Preferably, a cartridge filter or a pressure plate filter is used. Filtration can be performed with or without a filter aid. Suitable filter aids are filter aids based on diatomaceous earth, perlite and cellulose.

  Suitable centrifuges and separators are also known to those skilled in the art. Methods Technically, the centrifugation in the method according to the invention can be carried out by any centrifugation method and device known per se, such as the Ullmann's Encyclopedia of Industrial Chemistry, 7th edition, 2013 electronic edition, chapter: Those described in Centrifuges, Filtering und Centrifuges, Sedimenting can be used.

  Further, the catalyst can be separated by adding water as water extraction. To do so, the product mixture containing the alkyl (meth) acrylate which has not yet reacted, and optionally a separate azeotropic agent, and a stabilizer and catalyst, is contacted with water. A plurality of washing steps, for example, three washing steps may be performed. The amount of washing water is generally 0.1 to 2 times, preferably 0.2 to 0.5 times the product mixture per washing step.

  Washing can be performed, for example, in a stirred vessel or other conventional apparatus, such as a column or mixer / settler apparatus.

  Methods Technically, all the extraction and cleaning methods known per se, as well as cleaning devices such as, for example, Ullmann's Encyclopedia of Industrial Chemistry, 6th edition, 1999 electronic edition, chapter, are used for the washing in the method according to the invention. What is described in "Liquid-Liquid Extraction-Apparatus" can be used. This can be, for example, one or more stages, preferably one stage extraction, and extraction in co-current or countercurrent operation.

  In some cases, a storage stabilizer is added to the washed reaction mixture so that in the desired product, the stabilizer reaches a desired concentration, eg, 100 ppm. This concentration, which can be arbitrarily adjusted by the present method, is in the range of 15 to 200 ppm, for example for commercially available alkyl (meth) acrylates, depending on the specifications of the final product. Storage stabilizers are basically from the group of phenols such as 2,6-di-tert-butyl-4-methylphenol, 6-tert-butyl-2,4-dimethylphenol, hydroquinone and hydroquinone monomethyl ether. The stabilizer chosen is useful and hydroquinone monomethyl ether is preferred.

  Subsequently, in the distillation step (iii-d), unreacted alkyl (meth) acrylate, and optionally a separate azeotropic agent, and optionally water are distilled off from the product mixture. This distillation is generally carried out at a temperature of 40 to 100 ° C., preferably 60 to 80 ° C. and a variable pressure of 2 to 700 mbar. Furthermore, these components can also be removed by stripping with a gas, preferably an oxygen-containing gas.

  Separation by distillation is performed under reduced pressure, for example, in a stirring vessel having a double jacket heating section and / or an internal heating coil.

  Of course, the distillation can also take place in falling film evaporators or thin layer evaporators. To that end, the reaction mixture is preferably sent through the apparatus several times under circulation, under reduced pressure, for example 20-700 mbar, preferably 30-500 mbar, particularly preferably 50-150 mbar and at a temperature of 40-80 ° C. .

Advantageously, an inert gas, preferably an oxygen-containing gas, particularly preferably air, or a mixture of air and nitrogen (lean air) can be introduced into the distillation apparatus, which is based on the volume of the reaction mixture , for example 0.1~1m ³ / ^{m 3} h, preferably 0.2~0.8m ³ / ^{m 3} h, particularly preferably 0.3~0.7m ³ / ^{m 3} h.

  After performing steps (iii-c) and (iii-d), a product with high purity remains as the bottom product. This bottom product is generally at least 95% by weight, preferably at least 98% by weight.

  The subject of the present invention is also radiation curable of hydroxybenzophenone polyglycol ether (meth) acrylate having 5 to 100 ethylene oxide units and hydroxybenzophenone polyglycol ether (meth) acrylate having 5 to 100 ethylene oxide units. It is also used as a UV crosslinker in coating compositions.

  The following examples illustrate the invention in more detail.

Examples Example 1 Synthesis of hydroxyethoxybenzophenone (HEBP) 94.2 g (1.07 mol) ethylene carbonate, 206 g (1.02 mol) 4-hydroxybenzophenone (HBP), 4.5 g (0.030 mol) sodium iodide and 8.0 g toluene is pre-charged and slowly heated to 165 ° C. with stirring. Beyond 135 ° C, gas begins to evolve. Stir at 165 ° C. for 1 hour. After cooling to room temperature, water and toluene are added, the phases are separated, the organic phase is washed with water, dried and concentrated. Remove solid from toluene at room temperature and aspirate. 194 g (0.802 mol, 79% of theory) of a light beige solid are obtained.

Example 2 Synthesis of HEBP with 4 EOs 242 g (1.00 mol) of HEBP are precharged in an autoclave at 8O 0 C together with 834 mg (7.43 mmol) of KOtBu. 176 g (4.00 mol) of ethylene oxide are metered in at 120 ° C. and stirred at this temperature for 10 hours. After cooling to room temperature, volatiles are removed from the mixture on a rotary evaporator. 415 g of a brown liquid are obtained.
OH value = 139.6 mg KOH / g (theoretical value: 134.4 mg KOH / g).

  The hydroxyl value has an error of 4% from the theoretical value.

Example 3 Synthesis of HEBP with 9 EO 80.7 g (0.33 mol) of HEBP is pre-charged in an autoclave at 80 ° C. with 425 mg (3.79 mmol) of KOtBu. At 120 ° C., 132 g (3.00 mol) of ethylene oxide are metered in and stirred at this temperature for 10 hours. After cooling to room temperature, volatiles are removed from the mixture on a rotary evaporator. 210 g of a brown liquid are obtained.
OH value = 84.3 mgKOH / g (theoretical value: 87.8 mgKOH / g).

  The hydroxyl value has an error of 4% from the theoretical value.

Example 4 Synthesis of HEBP with 10 EOs 80.7 g (0.33 mol) of HEBP are precharged in an autoclave at 80 ° C. with 720 mg (6.43 mmol) of KOtBu. 279 g (6.33 mol) of ethylene oxide are metered in at 120 ° C. and stirred at this temperature for 3 hours. After cooling to room temperature, volatiles are removed from the mixture on a rotary evaporator. 368 g of a brown solid are obtained.
OH value = 53.1 mg KOH / g (theoretical value: 52.0 mg KOH / g).

  The hydroxyl value has an error of 2% from the theoretical value.

Example 5 Synthesis of HBP methacrylate with 5 EO Transesterification is performed while introducing air in a 750 mL double jacket reactor equipped with an anchor stirrer, air inlet, separation column and liquid distributor. In this apparatus, at room temperature, 347 g of HBP (5 EO), 0.1 g of methylhydroquinone (MEHQ) and 600 g of methyl methacrylate (MMA stabilized with 15 ppm of MEHQ) are preliminarily charged. 9.1 g of potassium phosphate are added and the reaction mixture is heated at a bath temperature of 100 ° C. The pressure is adjusted to 300 mbar (absolute pressure) and the azeotrope from methanol and MMA is continuously distilled off, where the bottom temperature is adjusted to 63-68 ° C. The reflux ratio varies between 2: 1 and 10: 1 (reflux amount: discharge amount). After completion of the reaction, the product is filtered through a paper filter and the reaction mixture is concentrated in vacuo. The conversion is determined by TAI NMR to be over 99%. The hydroxyl value is less than 2. The stabilizer content is 170 ppm MEHQ (specified by HPLC).

Example 6 Synthesis of HBP methacrylate with 10 EO In the apparatus of Example 5 at room temperature, 163 g benzophenone (10 EO), 0.06 g methylhydroquinone (MEHQ) and methyl methacrylate (stable with 15 ppm MEHQ) MMA) 400 g is charged in advance. 2.9 g of potassium phosphate are added and the reaction mixture is heated at a bath temperature of 100 ° C. The pressure is adjusted to 300 mbar (absolute pressure) and the azeotrope from methanol and MMA is continuously distilled off, where the bottom temperature is adjusted to 66 ° C. The reflux ratio varies between 2: 1 and 25: 1 (reflux amount: discharge amount). After completion of the reaction, the product is filtered through a paper filter and the reaction mixture is concentrated in vacuo. The conversion is determined by TAI NMR to be over 99%. The hydroxyl value is less than 2. The stabilizer content is 260 ppm MEHQ (identified by HPLC).

Example 7 Synthesis of HBP methacrylate with 20 EO In the apparatus of Example 5, at room temperature, 300 g benzophenone (20 EO), 0.08 g methylhydroquinone (MEHQ) and methyl methacrylate (stable with 15 ppm MEHQ) MMA) 600 g is charged in advance. 4.8 g of potassium phosphate are added and the reaction mixture is heated at a bath temperature of 100 ° C. The pressure is adjusted to 300 mbar (absolute pressure) and the azeotrope from methanol and MMA is continuously distilled off, where the bottom temperature is adjusted to 66 ° C. The reflux ratio varies between 5: 1 and 10: 1 (reflux amount: discharge amount). After completion of the reaction, the product is filtered through a paper filter and the reaction mixture is concentrated in vacuo. The conversion is determined by TAI NMR to be over 99%.

Comparative Example 1 Direct ethoxylation of hydroxybenzophenone (HBP) with 10 EO 496 g (2.50 mol) of hydroxybenzophenone together with 6.38 g of KOH aqueous solution (56.9 mmol KOH) were pre-charged in an autoclave, Dehydrate at 140 ° C. and 25 mbar for 2 hours. Within 12 hours at 140 ° C., 1100 g (25.0 mol) of ethylene oxide are metered in and stirred at this temperature for 8 hours. After cooling to room temperature, volatiles are removed from the mixture on a rotary evaporator. 1590 g of a brown liquid are obtained.
OH value = 105.8 mg KOH / g (theoretical value: 87.8 mg KOH / g).

  The hydroxyl value has an error of 21% from the theoretical value.

  This material was investigated by coupled LC-MS. This mixture contains not only the desired product, but also polyethylene glycol, polyethylene glycol bisbenzophenone, and hydroxybenzophenone trimer and higher homologues.

Comparative Example 2 Direct ethoxylation of HBP with 20 EO 297 g (1.50 mol) of hydroxybenzophenone together with 6.46 g of KOH aqueous solution (57.6 mmol of KOH) were precharged in an autoclave at 140 ° C. and 25 mbar. And dehydrate for 2 hours. Within 12 hours at 140 ° C., 1320 g (30.0 mol) of ethylene oxide are metered in and stirred at this temperature for 8 hours. After cooling to room temperature, volatiles are removed from the mixture on a rotary evaporator. 1610 g of a brown solid are obtained.
OH value = 79.0 mgKOH / g (theoretical value: 52.0 mgKOH / g).

  The hydroxyl value has an error of 52% from the theoretical value.

  This material was investigated by coupled LC-MS. This mixture contains not only the desired product, but also polyethylene glycol, polyethylene glycol bisbenzophenone, and hydroxybenzophenone trimer and higher homologues.

Comparison of hydroxyl values

Claims (14)

(I) a step of reacting hydroxybenzophenone with ethylene carbonate to form hydroxybenzophenone monoglycol ether;
(Ii) a step of ethoxylating hydroxybenzophenone monoglycol ether with ethylene oxide to form hydroxybenzophenone polyglycol ether;
(Iii) A method for producing hydroxybenzophenone polyglycol ether (meth) acrylate, comprising a step of transesterifying hydroxybenzophenone polyglycol ether and alkyl (meth) acrylate to form hydroxybenzophenone polyglycol ether (meth) acrylate.   The process according to claim 1, wherein in step (i), the reaction of hydroxybenzophenone and ethylene carbonate is carried out in the presence of sodium iodide.   The process according to claim 1 or 2, wherein 2 to 50 mol of ethylene oxide is reacted per 1 mol of hydroxybenzophenone monoglycol ether in the step (ii).   The process according to any one of claims 1 to 3, characterized in that in step (ii) the ethoxylation is carried out in the presence of potassium tert-butanolate as catalyst. Transesterification is performed in steps (iii-a) to (iii-d):
(Iii-a) Presence of an azeotropic agent that forms an azeotrope with an alkyl (meth) acrylate and hydroxybenzophenone polyglycol ether in the presence of a catalyst and a stabilizer, and an alcohol bonded in the alkyl (meth) acrylate. Reacting under,
(Iii-b) a step of continuously distilling off the azeotrope from the azeotropic agent and the alcohol, wherein steps (ii) and (iii) are carried out until the hydroxybenzophenone polyglycol ether is substantially completely reacted. Carried out at the same time,
(Iii-c) separating the catalyst from a hydroxybenzophenone polyglycol ether (meth) acrylate-containing product mixture;
(Iii-d) The process according to any one of claims 1 to 4, comprising the step of distilling off the unreacted alkyl (meth) acrylate and azeotropic agent from the product mixture. .   The production method according to claim 5, wherein the azeotropic agent is an alkyl (meth) acrylate.   6. The production method according to claim 5, wherein the azeotropic agent is a separate solvent different from the alkyl (meth) acrylate.   The method according to claim 7, wherein the azeotropic agent is selected from the group consisting of n-heptane and cyclohexane.   The production method according to any one of claims 5 to 8, wherein the catalyst used in the step (iii-a) is potassium phosphate.   The production method according to any one of claims 5 to 9, wherein the stabilizer used in step (iii-a) is hydroquinone monomethyl ether.   The production method according to any one of claims 1 to 10, wherein the alkyl (meth) acrylate used in step (iii) is methyl (meth) acrylate or ethyl (meth) acrylate.   Hydroxybenzophenone polyglycol ether (meth) acrylate having 5 to 100 ethylene oxide units.   The hydroxybenzophenone polyglycol ether (meth) acrylate according to claim 12, which can be produced by the production method according to any one of claims 1 to 11.   Use of hydroxybenzophenone polyglycol ether (meth) acrylates having 5 to 100 ethylene oxide units as UV crosslinkers in radiation curable coatings.