JPS6219450B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing liquid polyglycidyl ethers of polyhydric phenols, particularly dihydric phenols such as 2,2-bis(4-hydroxyphenyl)propane.

Liquid diglycidyl ethers of dihydric phenols can be represented by the following general formula.

where n is a small average
value) is, for example, less than 0.25, ideally 0, and R is the hydrocarbon residue of the divalent phenol HO-R-OH. These glycidyl ethers are generally produced by reacting divalent phenols with epichlorohydrin and an alkali metal hydroxide, usually sodium hydroxide, at elevated temperatures according to the following theoretical formula: However, during practice, a wide range of by-products are usually produced due to the high reactivity of the components. for example,
In order to prevent as much as possible the formation of compounds of formula () in which n has a value of 1 or greater, epichlorohydrin must be used in large excess. The presence of these components increases the viscosity and epoxy molar mass of the product.

Additionally, some of the epichlorohydrin can be hydrolyzed under the reaction conditions to give products such as glycidol and glycerol, or polymerized to give insoluble polymeric materials. Hydrolysis of glycidyl ether groups (or reaction of phenolic hydroxyl groups with glycidol) provides alpha glycol groups, thereby reducing the specific epoxy content required for the curing reaction.

Further complications may arise from the mechanism of the reaction (), which is generally considered to occur in two steps, i.e. the first step involves the addition of the phenolic hydroxyl group to the epoxy group in the presence of a catalyst ( or condensation) with the formation of chlorohydrin ether, [In the formula, R′ is a phenol residue] and the second
The step is dehydrochlorination of the chlorohydrin ether to give the glycidyl ether with an alkaline substance (usually NaOH): Under the operating conditions of production, the last traces of chlorohydrin ether are rather difficult to dehydrochlorinate. They require an excess of alkaline material, which can further induce the formation of by-products.

Additionally, chlorohydrin ethers and epichlorohydrin can be trans-epoxidized in the presence of a catalyst with the formation of dichlorohydrin, which can lead to other complications: In order to improve in some way the quality of the product (low viscosity, low epoxy molar mass, low chlorine content, low color values are desired) or the economics of production (low loss of epichlorohydrin, process Many methods have been proposed to improve the ease of handling of flow at some point in the process.

Although steps () and () can occur concomitantly, many proposed processes prefer to carry out these steps sequentially, so that condensation (step )
occurs to a certain extent. In such multi-step processes, the condensation step includes catalytic amounts of alkaline substances (NaOH or tertiary amines) or catalytic amounts of water-soluble ionizable halides (quaternary ammonium, lithium, sodium, potassium; chloride, bromide). , or as iodide). In one type of multi-step method,
Excess epichlorohydrin (and other volatiles) is removed after condensation by distillation, and the residue is
Mainly dichlorohydrin ether is dehydrochlorinated with alkaline substances (UK No. 897744,
US No. 294309516, US No. 3023225, US No.
No. 3352825). Another type of multi-step process uses, for example, solid NaOH or epichlorohydrin in the presence of excess epichlorohydrin and all other products, keeping the amount of water present very low. Dehydrochlorination is carried out by removing most of the water by azeotropic distillation with phosphorus (UK No. 1278737, US No. 3069434, US No.
No. 3221032, US No. 3309384, US No. 3980679
issue). The solid NaCl formed must then be removed in a further step by filtration or by dissolving it in water, and the excess epichlorohydrin is distilled off after dehydrochlorination.

In order to improve the yield and reduce the chlorine content of the product, dehydrochlorination in the presence of epichlorohydrin can be carried out with a slightly insufficient amount of alkali, and the product After removal of epichlorohydrin, it may be dehydrochlorinated, preferably carried out using diluted aqueous NaOH in excess of the saponifiable chlorine in the solvent (US No.
2841595, UK No. 1278737).

To avoid the problems associated with solid NaCl handling and azeotropic removal of water, especially in continuous processes, the etherification of polyhydric phenols was performed using epichlorohydrin and aqueous sodium hydroxide with isopropyl alcohol (U.S. No. 2,848,435). It was proposed to carry out the process in the presence of water, in the presence of acetone (US No. 2,986,551) or acetone (US No. 2,986,551). However, these methods differ in product quality (high values of epoxy molar mass, chlorine content, and viscosity).
Alternatively, it is disadvantageous in terms of economy (loss of epichlorohydrin). In summary, known processes for the production of liquid polyglycidyl ethers of polyhydric phenols usually suffer from one or more disadvantages, such as: undesirable amounts of by-products such as polymer compounds; , epichlorohydrin hydrolysis products, solvent-derived products, etc.; of products with high viscosity, high epoxy molar mass, high content of saponifiable chlorine, high content of alpha glycol. production; loss of reactants and products in waste salts; operational difficulties (especially in continuous operation).

A new method has been discovered which is substantially free from the above-mentioned difficulties. The new method is compatible with batch or continuous operation.

The process for producing liquid polyglycidyl ethers of polyhydric phenols according to the present invention comprises: (A) at a temperature of 70°C to
polyhydric phenol and a molar excess of epichlorohydrin in the presence of a water-soluble ionizable alkali metal, ammonium or phosphonium halide as a condensation catalyst and in the absence of an alkali metal hydroxide at 130°C. (B) diluting the product of step (A) with 40 to 80 percent by weight of a water-soluble organic solvent that is a monohydric alcohol or ketone and optionally water; step with an aqueous solution of alkali metal hydroxide at a temperature below 65° C., such that the amount of water in (B) is sufficient to keep the alkali metal halide in solution;
and separating the aqueous alkali halide solution from the organic phase in one or more stages, and (C) recovering the polyglycidyl ether from the final organic phase obtained in step (B).

The polyhydric phenols are preferably dihydric phenols such as diphenylolpropane (bisphenol A), diphenylolethane, diphenylolmethane (bisphenol F), or mixtures thereof such as bisphenol A and bisphenol F.
It is a mixture of 70:30 weight ratio. Bisphenol A is preferably P.P' isomer 2.2-bis(4
-hydroxyphenyl)propane. Other polyhydric phenols that can be used are 1, 1, 2, 2
-tetra(4-hydroxyphenyl)ethane.

The epichlorohydrin added in step (A) should be in large molar excess relative to the polyhydric phenol, preferably in a molar ratio of 5:1 to 20:1, preferably in a molar ratio of 8:1 to 12:1. is particularly preferred. Such molar ratios are commonly used to produce polyglycidyl esters having low molecular weights and low viscosities (80-100 poise at 25°C). If relatively high viscosity polyglycidyl ethers are desired (100-150 poise at 25°C), the epichlorohydrin/polyhydric phenol molar ratio is preferably 5:1.
or 8:1.

The reaction mixture of step (A) may further contain small amounts of water and/or organic solvents as used in step (B);
These may serve to dissolve the catalyst, and preferably the catalyst is first dissolved in water and the catalyst solution is added. Small amounts of water, solvents and minor components of other volatiles may be present in the excess of epichlorohydrin recovered after the dehydrochlorination step, and the recovered epichlorohydrin is again subjected to step (A).
It can be used in

The amount of water in step (A) can range from 0.05 to 8 percent by weight, based on the total weight in step (A), depending on the catalyst and temperature used. At 70°C the amount of water is preferably kept below 6 weight percent and at 95°C preferably below 2 weight percent, the relatively high amount of water promoting side reactions such as hydrolysis of epichlorohydrin. It is possible. The amount of organic solvent can range from 0 to 5 weight percent, and is preferably less than 3 weight percent, more preferably 0 to 2 weight percent.

The catalyst in step (A) is a water-soluble ionizable halide. "Water-soluble" in this description means that the catalyst should be soluble in the initial mixture, and the presence of water may be required to achieve such solubility. Suitable types of catalysts are quaternary ammonium halides, quaternary phosphonium halides, and alkali metal halides, where the halides are preferably chlorides or bromides. Examples of quaternary ammonium halides are tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium chloride, tetraethylammonium bromide, benzyltriethylammonium chloride, benzyltrimethylammonium bromide. Examples of quaternary phosphonium halides are ethyltriphenylphosphonium chloride, bromide, and iodide. Examples of suitable alkali metal halides are lithium chloride, sodium chloride, sodium bromide, potassium chloride, and potassium bromide. The amount of catalyst to be used is
It depends on the activity to carry out the etherification (reaction) at the reaction temperature and to the desired extent in a suitable time, for example within 4 hours. The amount of catalyst ranges from 0.25 to 10 mole percent (%) based on the polyhydric phenol.
m). Quaternary ammonium halides and quaternary phosphonium halides are 0.5
The alkali metal halides may be used in amounts of 0.5 to 10% m. For example, lithium chloride can be used in an amount of 0.5 to 5%m and sodium chloride in an amount of 2 to 10%m. The halide is preferably added as an aqueous solution, for example sodium chloride
It may be added as an aqueous solution of 25% w to 25% w, preferably 20% w.

The temperature in step (A) should be in the range 70 to 130°C, preferably in the range 70 to 90°C. If the mixture contains more than 0.5%w water, the temperature should not be raised above 100°C to avoid side reactions. Acceptable reaction times can range from 30 minutes to 4 hours, depending on the catalyst, temperature, and desired degree of etherification or phenol conversion. The degree of phenolic conversion is defined as the percentage of phenolic hydroxyl groups converted to ether groups. If the degree of phenol conversion exceeds 99% in step (A), side reactions may occur. Process (A)
The phenol conversion of is preferably kept between 30 and 95%, more preferably between 40 and 90%. Below 60°C, etherification is very slow, so reaction times on the order of days rather than hours may be required in step (A) to obtain sufficient phenol conversion. At temperatures at or above the boiling point, the reactor should be pressurized or equipped with a reflux condenser. Moderate temperatures (70-90°C) are more preferred in order to keep the amount of by-products and undesired intermediates (alpha-chlorohydrin, beta-chlorohydrin) low. The reactor preferably has an agitator. The reaction mixture in step (A) is initially a one-phase liquid system. If the catalyst is sodium chloride, some of it will pass through step (A).
An aqueous phase may be formed during step (A), or if more water is added to prevent this crystallization (up to 8% w). However, the process
The final mixture of (A) can then be used for step (B) without settling such foreign phases.

The reaction in step (A) is mainly the production (reaction) of chlorohydrin ether.

Sequentially in step (B), the entire product of step (A) is diluted with a water-soluble organic solvent, the water-soluble organic solvent being a monohydric alcohol or a ketone, and optionally diluted with water, and the temperature is adjusted as required. 65℃ by cooling
lowered to less than

Water-soluble monohydric alcohols and ketones generally have up to 4 C atoms per molecule. Examples include methanol, ethanol, n-
Examples include propanol, isopropyl alcohol, butanols, acetone, and methyl ethyl ketone. Preference is given to solvents which are miscible with water in all proportions. It should be noted that solubility here refers to solubility in water and not in aqueous salt solutions. The presence of these solvents in step (B) is an essential condition of the method of the invention. The solvent allows fast dehydrohalogenation at fairly low temperatures, whereby side reactions such as hydrolysis of epichlorohydrin, the amount of undesired by-products can be minimized.

The preferred solvent in step (B) is isopropyl alcohol. Its advantages are very fast dehydrochlorination, very high selectivity, and very low hydrolytic losses of epichlorohydrin.

Preferred temperatures during dehydrohalogenation in step (B) range from 35 to 55°C, particularly preferred temperatures from 40 to 50°C.

The amount of solvent added in step (B) is the same as that in step (A).
from 40 to 80 percent, preferably from 50 to 70 percent, by weight of the product.

Water should be present in an amount sufficient to form the alkali metal halide in aqueous solution. for example,
If the dehydrochlorination is carried out with aqueous sodium hydroxide, 2 mol of sodium chloride are produced per mole of dihydric phenol, and the total amount of water at the end of step (B) is then 2 mol per mole of dihydric phenol. Should be at least 330g. about
To obtain a concentrated brine of 20 to 17.5 weight percent sodium chloride, an amount of water of 450 to 550 g per mole of dihydric phenol is preferred. Brine at this concentration is largely free of organic solvent and has sufficient density to readily separate from the organic phase. Brine less than 15%w is one that does not easily separate from the organic phase.
Water can be added neat or mixed with the solvent. At least a portion thereof is added in the form of an aqueous solution of alkali metal hydroxide.

The alkali metal hydroxide is preferably sodium hydroxide, and it is added in step (B) preferably as a 20 to 50% w aqueous solution, such as a commercially available solution. The amount of alkali metal hydroxide added in step (B) may be from 1.5 to 2.5 mol, preferably from 1.8 to 2.1 mol, all per mol of original dihydric phenol. The aqueous alkali metal hydroxide may be metered at a constant rate or at a variable rate;
Alternatively, it may be added in portions in multiple stages, where each portion is added over, for example, 5 minutes and the reaction is continued for a reaction time on the order of 10 to 30 minutes, with the brine removed after each stage. Since the reaction mixture becomes heterogeneous, the entire mixture is kept in turbulent motion during the addition of the alkali metal hydroxide and during the subsequent reaction time, for example by stirring. The alkali metal halide formed dissolves in the water present and the mixture separates into two phases: an organic phase and an aqueous phase, brine. Concentrated brines have a relatively large density and can be settled as a bottom layer, for example by gravity settling or by centrifugation.
It can be separated from the organic phase in one or more stages. The mesophase is usually clear due to the absence of polymer or gel particles. The separated brine can be stripped to recover the solvent and epichlorohydrin.

The reaction in step (B) mainly consists of dehydrochlorination (reaction) of the chlorohydrin ether produced in step (A), and also a large amount of dissolved NaCl/
The etherification (reaction) of phenolic groups followed by dehydrochlorination catalyzed by NaOH.

The organic phase containing the polyepoxide must be washed with water to remove any alkali metal chlorides and hydroxides it contains.
To facilitate phase separation after washing, the density of the organic phase can be reduced, e.g. by adding more epichlorohydrin or by distilling off part of the solvent under reduced pressure, e.g. at a temperature below 80 °C. It may have to be increased first by The wash water, which also contains small amounts of solvent and epichlorohydrin, can be recycled to the dehydrochlorination step. The polyepoxide can then be recovered from the last organic phase by distilling off most of the solvent and epichlorohydrin, preferably in two stages, leaving a first distillate containing most of the solvent and a first distillate containing mainly epichlorohydrin. It is also possible to obtain a second distillate consisting of: The last traces of epichlorohydrin can be distilled off in vacuo, for example by steam injection. The recovered solvent and epichlorohydrin distillate are each
(B) and can be recycled to step (A).

The polyepoxide is recovered from the distillation as a residue. The content of saponifiable chlorine can be reduced to very low values by further dehydrochlorination with an excess of preferably dilute aqueous alkali metal hydroxide with respect to the amount of saponifiable chlorine. For subsequent dehydrochlorination, the crude polyepoxide may be diluted with organic solvents such as toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, and mixtures with, for example, isopropyl alcohol. Post-dehydrochlorination is preferably carried out using a dilute alkaline solution containing, for example, 2 to 20% w of sodium hydroxide at a temperature of 60 to 120° C. for a period of 30 minutes to 3 hours. The amount of alkali is preferably a 2 to 25 times excess over the calculated amount. The separated aqueous layer, which is still alkaline, can be used as alkaline feed in step (B). The organic phase can then be washed with water or dilute sodium phosphate solution, the solvent can be removed by distillation, and the purified liquid polyepoxide can be recovered as a residue.

The liquid polyglycidyl ethers produced by the process according to the invention have a very good coloration, usually less than 1 on the Gardner scale, a low content of alpha-glycol and phenolic hydroxyl groups, a low content of fixed chlorine and Polyglycidyl ethers with oxidizable chlorine and low viscosity can be easily produced. Furthermore, the chemical loss of epichlorohydrin is very low, usually lower than 10 g/Kg resin, and the recovered epichlorohydrin has a low dichlorohydrin content and can be used again without further purification. . No filtration of large amounts of NaCl is required, and the liquid phase (brine, organic phase)
separates easily. Polymer formation is so low that it can be ignored.

The present invention will be explained by examples. Parts herein are parts by weight. Diphenylopropane is 2,2-bis(4-hydroxyphenyl)propane.

Example Process (A).

Diphenylopropane 228 parts (1 mole) Epichlorohydrin 925 parts (10 mole) NACl (20% w in water) 5 parts (0.085 mole) were heated at 100° C. for 3 hours with stirring. Phenol conversion was 52%. Some of the NaCl precipitated during the reaction.

Process (B).

The product of step (A) was cooled to 45°C and isopropanol (540g) and water (135g) were added. While maintaining the temperature at 45° C., 400 parts of a 20% w NaOH aqueous solution (2 mol) was added over 5 minutes with stirring. The mixture was kept at 45°C for 15 minutes. After settling for 2 minutes, the aqueous bottom layer was separated and the organic layer was diluted with epichlorohydrin (200 parts) and washed with water (20% v). The organic bottom layer is flash distilled in two stages, and the low boiling distillate (540 parts) is 56% w.
of isopropyl alcohol, 30% w of epichlorohydrin and 14% w of water. High boiling distillate (965 parts) is 77% w epichlorohydrin;
It contained 15% w isopropyl alcohol, 7% w water and 1% w impurities. The residue was steam stripped in vacuo to remove traces of volatile material.

Process (C).

Residue from step (B) (342 parts, saponifiable Cl 1.0%
dilute w) with toluene (150% v) and 200
while stirring with 5% aqueous caustic solution (2.5 mol NaOH/1 eq. saponifiable Cl)
Heated at 85°C for 2 hours.

The organic layer was washed with 2% w aqueous NaH ₂ PO ₄ solution and the toluene was distilled off. Trace volatiles were removed in vacuo at 170°C.

The product (339 parts) was a liquid polyglycidyl ether of diphenylolpropane with the following properties:

Epoxy molar mass 182 Viscosity (at 25℃) 85 poise Color (Gardner) 0.4 Saponifiable Cl 0.1%w Total Cl 0.18%w Phenolic hydroxyl group 2 mmol/100g Alpha glycol content 4 mmol/100g Volatile matter <100ppm Example Process (A).

Diphenylopropane 228 parts (1 mole) Epichlorohydrin 1120 parts (12 moles) NaCl (20%w in water) 5 parts (0.085 moles) were heated at 90°C for 3.5 hours. Phenol conversion is 56
%, and a small amount of NaCl precipitated during the reaction.

Steps (B) and (C).

The product of step (A) was cooled to 40°C and isopropanol (600 parts) and water (150 parts) were added. While stirring and maintaining the temperature at 40°C, 380 parts of a 20% w aqueous caustic solution (1.9 mol) was added over 5 minutes. The mixture was further stirred for 15 minutes. After settling for 2 minutes, the brine was separated.
The organic phase was treated twice with 30 parts of 20% w aqueous caustic solution, stirred for 5 minutes each time at 40°C, and the brine was allowed to settle and separate. The final organic layer was dissolved in water (15%).
v) twice, the solvent was removed by flash distillation and the residue was steam stripped in vacuo.

The liquid polyglycidyl ether (338 parts) had the following properties: Epoxy molar mass 180 Viscosity (at 25°C) 80 Poise color (Gardner) 0.5 Saponifiable Cl 0.1%w Total Cl 0.17%w Phenolic hydroxyl groups 2 mmol/100 g Alpha-glycol content 3.5 mmol/100 g Volatiles <100 ppm Example The example is repeated except that NaCl in step (A) is replaced by KCl (0.01 mol, dissolved in 20 parts of water). Ta. The phenol conversion after step (A) is 62
It was %.

The liquid polyglycidyl ether (339 parts) had the same properties as in the example.

Example In step (A), NaCl was replaced with LiCl (0.01 mol, water 20
The example was repeated except that the solution was replaced with Phenol conversion after step (A) is 86%
It was hot.

The liquid polyglycidyl ether (340 parts) had the following properties: Viscosity (at 25°C) 80 poise Saponifiable Cl 0.10% w Total Cl 0.22% w Color (Gardner) 4 Example In step (A) NaCl to tetramethylammonium chloride (0.01 mol, dissolved in 30 parts water)
The example was repeated except that . After step (A), the phenol conversion was 90%.

The liquid polyglycidyl ether (338 parts) had the following properties: Viscosity (25°C) 71 poise Saponifiable Cl 0.2%w Total Cl 0.4%w Color (Gardner) 0.8 This experiment was repeated, but here Now, tetramethylammonium chloride (0.01 mol) was dissolved in 1.1 parts of water.

In this case, the liquid polyglycidyl ether is heated at 25°C.
had a viscosity of 81 poise, other properties being the same.

Example Step (A) of the example was repeated.

Process (B).

The product of step (A) was cooled to 45°C and isopropanol (720 parts) and water (180 parts) were added. 420 parts of 20% w aqueous caustic solution (2.1 mol) while stirring and keeping the mixture at 45°C.
was added over 5 minutes and the mixture was further stirred for 15 minutes. After settling for 2 minutes, the brine was separated.

Process (C).

The organic phase was washed twice with water (20% v), the solvent was removed by flash distillation and the residue was steam stripped in vacuo.

The residue (340 parts, saponifiable Cl (0.7% w)) was further processed as in Example, step (C).

The liquid polyglycidyl ether (338 parts) had the following properties: Epoxy molar mass 181 Viscosity (at 25°C) 75 Poise color (Gardner) 0.6 Saponifiable Cl 0.08%w Total Cl 0.18%w Phenolic hydroxyl groups 2.5 mmol/100 g Alpha-glycol content 4 mmol/100 g Volatiles <100 ppm Example The example was repeated except that 228 parts of diphenylolpropane was mixed with diphenylolpropane (152 parts; 2/3 mole) and enylolmethane (67
1/3 mol).

Liquid mixture of polyglycidyl ethers (328
) had the following properties: Epoxy molar mass 175 Viscosity (at 25°C) 55 poise Saponifiable Cl 0.1% w Example Step A: 50.0 Kg (219 mol) of bis in a 0.5 m ³ reactor. Phenol A, 203.0 Kg (2195 mol) of epichlorohydrin, and 0.22 Kg of tetramethylammonium chloride were charged. The mixture was heated to 116°C for 1 hour, followed by refluxing at 119-122°C for 1 hour. The mixture was cooled to room temperature.

Step B In a 1 liter continuously stirred tank reactor kept at 45°C, 834 g/h of the mixture obtained in step A (equivalent to 0.72 mol/h bisphenol A), 620 g/h acetone/water ( 4/1 weight ratio)
and 291 g/h of aqueous 20%w NaOH were continuously fed. The reaction effluent was fed to a settler from which 1424 g/h of organic solution was obtained and worked up in batches.

The volume of solution obtained in 1 hour was washed once with 20% v water and the solvent was removed by flash distillation. Resin yield: 256 parts (saponifiable Cl: 3.1%
w).

Step B was repeated, but 640 g/h of isopropyl alcohol/water (4/1 weight ratio) was fed to the reactor instead of acetone/H ₂ O. The reactor effluent (1419 g/h) was worked up to finally obtain 246 parts/h of resin (saponifiable Cl 0.91%w).
Both products were treated as in step C of the example.
Treated with excess aqueous caustic solution. The resin had the following properties: Epoxy molar mass: 185-186 Viscosity (at 25°C): 115-123 Poise color (Gardner): 0.6-0.8 Saponifiable Cl: 0.10%w Total Cl: 0.35 %w Phenolic hydroxyl group: 2 mmol/100g Alpha-glycol: 2 mmol/100g

Claims (1)

[Scope of Claims] 1. A method for producing liquid polyglycidyl ethers of polyhydric phenols, which comprises: (A) controlling the amount of water produced or present in this step to less than 8% by weight;
polyhydric phenol and a molar excess of epichlorohydrin in the presence of a water-soluble ionizable alkali metal, ammonium or phosphonium halide as a condensation catalyst and in the absence of an alkali metal hydroxide at 130°C. (B) diluting the product of step (A) with 40 to 80 percent by weight of a water-soluble organic solvent that is a monohydric alcohol or ketone and optionally water; step with an aqueous solution of alkali metal hydroxide at a temperature below 65° C., such that the amount of water in (B) is sufficient to keep the alkali metal halide in aqueous solution;
and separating the aqueous alkali halide solution from the organic phase in one or more stages, and (C) recovering the polyglycidyl ether from the final organic phase obtained in step (B). 2. The method according to claim 1, wherein the polyvalent phenol is a divalent phenol. 3. The method according to claim 2, wherein the divalent phenol is 2,2-bis(4-hydroxyphenyl)propane. 4. A method according to any one of claims 1 to 3, wherein the molar ratio of epichlorohydrin to polyhydric phenol is from 5:1 to 20:1. 5. A method according to any one of claims 1 to 4, wherein the water-soluble ionizable halide is a quaternary ammonium halide. 6 Claims 1 to 6, wherein the water-soluble ionizable halide is an alkali metal halide.
The method described in any one of Section 4. 7. The method according to any one of claims 1 to 6, wherein the temperature in step (A) is 70 to 90°C. 8 30 or more of the initially present phenolic group
8. A process according to any one of claims 1 to 7, wherein step (A) is stopped when 95% have been converted to ether groups. 9. The method according to any one of claims 1 to 8, wherein the water-soluble organic solvent added in step (B) is isopropyl alcohol. 10. The method according to any one of claims 1 to 9, wherein the temperature in step (B) is 35 to 55°C.