DE1176665B - Process for the preparation of bromomethyl-4-alkylphenols - Google Patents

Description

Process for the preparation of bromomethyl-4-alkylphenols The preparation of alkyl-substituted halomethylphenols, which are an aliphatic hydrocarbon radical containing at least 4 carbon atoms is already known.

According to the method of German Patent 682 138, the succeeds Introduction of chloromethyl groups into the alkylated phenols by the action of Aqueous formaldehyde solutions saturated with hydrogen chloride to the corresponding alkylated phenols, and according to the method of German patent 690 781 the same compounds are obtained by the action of hydrogen halide up to for saturation on the preformed methylol compounds of the alkylated phenols.

In this known process, instead of the methylol compounds also that caused by the alkaline condensation of formaldehyde with the alkylated phenols available mixtures of monomethylol compounds and those already further condensed Methylol compounds can be used.

With hydrogen chloride, mainly monochloromethyl-alkylphenols are formed with a chlorine content of about 9 to 18% in addition to dichloromethylalkylphenols with corresponding higher chlorine content.

When using hydrogen bromide, the result is accordingly compared to chlorine, the atomic weight of bromine is about twice as high as mono- and di-bromomethyl-alkylphenols with an even higher halogen content.

It has now been found that technically valuable products can be obtained when the methylol groups are used in the production of bromomethyl-4-alkylphenols only partially converted to bromomethyl groups. According to the method of the invention Compounds or mixtures that can be produced are and are deformable elastomers especially used as a vulcanization accelerator.

The invention relates to a process for the production of bromomethyl-4-alkylphenols, which may still contain methylol groups by reacting gaseous or aqueous Hydrogen bromide with methylol compounds of 4-alkylphenols, their alkyl groups contain at least 4 carbon atoms, optionally in the presence of solvents, which is characterized in that either a) the 2-mono- or 2,6-dimethylol-4-alkylphenol, the alkyl radicals of which contain 4 to 20, preferably 6 to 10 carbon atoms, or b) by partial condensation of the 2-mono- or 2,6-dimethylol-4-alkylphenol received Oligomer with an average of up to four phenol units or c) a mixture from the 4-alkylphenol with that required for the formation of the mono- or dimethylolphenol Amount of formaldehyde brominated with such an amount of hydrogen bromide that the obtained Mixture has a bromine content of about 1 to about 90 / o, preferably about 4 to 5%, and that the resulting mixture is distilled in a manner known per se dehydrated in vacuo and optionally into the oligomers in a manner known per se transferred with up to four phenolic units.

The bromination is preferably carried out with such alkylphenols by whose alkyl radical is a tertiary butyl group, an amyl group or a diisobutyl group (Ditertiary octyl group).

For the preparation of the starting compounds, in the context of the present Invention Protection not sought.

The reaction mixtures obtained in the process of the invention contain methylol phenols, bromomethyl phenols and bromomethyl methylol phenols which have the general formulas below.

In these general formulas, R represents an alkyl group with 4 to 20 carbon atoms and n is a number between 0 and 2. When in the above general formulas the resitols with methylene ether bonds, -CH20CH2-, between the phenolic rings are shown, it is only about the ideal case, because in fact some phenolic rings are linked directly to one another by methylene bonds, CH2 be. One or more compounds of this type can be present in the mixture obtained to be available.

It is critically important that the quantitative ratio between hydrogen bromide and alkylene phenols is chosen so that the bromine content in the end product is between about I and 9% and preferably between 4 and 5%.

When using a phenol-formaldehyde resin to determine its content If hydrogen bromide is added to ether groups, the amount of bromine added is approximately between 25 and 50 percent by weight of the resulting phenol. Such high Bromine additions are outside the scope of the present invention, and Compounds with a high bromine content are not used as a vulcanization accelerator suitable for butyl rubber.

It should be noted that the chloromethylphenols and resitols by no means are analogous to the bromine compounds prepared by the process of the invention, since the chlorine compounds tend to decompose the butyl rubber and continue to do so Aging and bending properties give significantly worse than those with Properties generated using the bromine compounds are.

The products which can be produced by the process of the invention can also to create shaped products, e.g. B. cups, serve.

The oligomers (resitols) used as the starting compound, the obtained by partial condensation of the 2-mono- or 2,6-dimethylol-4-alkylphenol have an average molecular weight no higher than that of a tetramer is, but can also be that of a dimer or trimer.

The following methylol compounds are, for example, the starting compounds suitable: 2,6-dimethylol-4-tertiary-butylphenol, 2,6-dimethylol-4-tertiary-amylphenol, 2,6-dimethylol-4-tt-octylphenol, 2,6-dimethylol-4-dodecylphenol, 2,6-dimethylol-4-eicosylphenol, 2-methylol-4-tt-octylphenol, 2-methylol-4-n-octylphenol, 2-methylol-4-n-hexylphenol, 2-methylol-4-tert-butylphenol and 2-methylol-4-eicosylphenol.

The bromination is usually complete, and normally the bromine contained in the hydrobromic acid added to the reaction mixture to more than 80 ° l "and sometimes even up to 100% in the bromomethyl groups.

If you use the 4-alkylphenol, formaldehyde and hydrogen bromide for the purpose Formation of the bromomethyl group simultaneously brings about the implementation, according to experience the resulting bromomethyl-4-alkylphenol in far less, for example only the half the amount should be applied than is otherwise the case when the hydrogen bromide with the preformed methylolalkylphenols or -resitolen for Implementation is brought.

The formaldehyde is with the alkylphenol in the ratio between about Brought 0.5 to about 2.1 moles per mole of alkylphenol to react. The implementation of the Hydrogen bromide with the methylolalkylphenol can either be present or in Absence of water can be carried out. If necessary, any existing Water removed by vacuum distillation before or after the addition of hydrogen bromide will. The oligomers (resitols) are usually first in an inert solvent dissolved and only then treated with hydrogen bromide. Used as an inert solvent z. B. Benzene, toluene, xylene, and naphtha (a mixture of volatile hydrocarbons) used. Resitols made from low molecular weight alkylphenols are usually used an aromatic hydrocarbon is used as a solvent while for the from higher molecular weight alkylphenols, e.g. B. tertiary octylphenol, obtained resitols also aliphatic hydrocarbons, for example n-heptane, n-hexane and gasoline, can be used.

When the alkylphenol, the formaldehyde and the hydrogen bromide at the same time be brought to implementation, this can either in the presence or in the absence by water or an organic solvent. Among the usable organic solvents include the hydrocarbons already mentioned. Preferably However, the reaction takes place in the presence of water, which is achieved by using aqueous Formaldehyde solution or aqueous hydrobromic acid can be introduced. Possibly however, the formaldehyde can also be in the form of paraformaldehyde or trioxane and the Hydrogen bromide are supplied in gaseous form.

The reaction temperature is not critical and it can be between Room temperature and 100 ° C. If the reaction temperature is too high, the tendency arises to an undesirable loss of bromine in the compound as a result of further polymerization.

The following examples serve to illustrate the invention, wherein Unless stated otherwise, all parts and percentages are based on weight are.

Example 1 (procedure b) a) Production of the starting resitol 2000 g of p-diisobutylphenol and 1060 g of 15% sodium hydroxide solution are added with stirring 95 ° C and kept at this temperature until all of the p-diisobutylphenol has gone into solution. The aqueous sodium alkylphenolate solution is first on Cooled 50 ° C and then treated with 1260 g of 37% formaldehyde, the temperature is kept at 48 to 50 ° C. After adding the formaldehyde, the mixture becomes Maintained at this temperature of 48 to 50 ° C. for a further 12 hours. The salary the free formaldehyde is less than 1.5%. After that, the mixture is diluted with Hydrochloric acid neutralized at 40 to 45 ° C to a pH value of 3.5 and then Bender Remove the water again to remove salts and excess Hydrochloric acid washed several times with water. The resol obtained in this way (mono- and dimethylol-p-diisobutylphenol) is then dehydrated or partially polycondensed that it is at a pressure distilled from 686 mm of mercury, heated to 125 to 130 ° C and at these temperatures and pressing is held until the resitol stage, namely a brittle resin, is reached is. Then the resin is taken out of the flask and allowed to cool.

Its average molecular weight corresponds to that of a tetramer; F. (according to the capillary method) 50 ° C. b) Brief bromination 800 g of the according to a) produced resin are at 35 ° C with stirring until completely dissolved in 800 g of benzene dissolved. Then 40 g of hydrogen bromide at 25 to 30 ° C under vigorous Stir blown under the surface of the resin solution.

Immediately after this addition of the gaseous hydrogen bromide the benzene becomes the resin solution by vacuum distillation at a pressure of 686 mm of mercury and 95 ° C removed and the bromomethyl and methylol-octylphenol oligomer mixture taken out of the flask and allowed to cool. F. (using the capillary method) 43 ° C ; combined bromine 4.2%. c) Longer bromination 680 g of that obtained according to a) Resin are dissolved in 680 g of benzene. 32 g of gaseous hydrogen bromide are added to the solution blown under the surface of the liquid at 22 to 30 ° C. After the addition of hydrogen bromide the mixture is stirred at room temperature for several hours. After removing of benzene by vacuum distillation at a pressure of 686 mm of mercury and 85 ° C, the resin is removed from the flask and cooled; F. (using the capillary method) 50 ° C; bound bromine 4.20 / o.

Example 2 (procedure a) a) Production of the starting resol 2000 g (1 mol) of p-diisobutylphenol are mixed with 1060 g of 15% aqueous sodium hydroxide solution added, and the mixture is heated to 95 ° C. The solution is then about 45 Cooled to 50 ° C and then with stirring and constant cooling to 40 to 50 ° C with 1260 g (1.5 mol) 370% formaldehyde. This temperature then becomes Maintained for about 10 hours, after which time less than 1.5% free formaldehyde remains behind.

The mixture is then adjusted to pH with dilute hydrochloric acid of 3.5 neutralized and then to remove the sodium chloride and excess Hydrochloric acid washed several times with water, neutralizing and washing water can be removed by decanting. It is vigorously stirred each time it is washed. In this State, the resole contains approximately 10 to 15% mechanically entrapped water. b) Bromination in the absence of water and subsequent partial condensation 1178g des Resols prepared according to a) (mono- and dimethylol-p-diisobutylphenol) are used for the purpose Removal of the mechanically trapped water and also for the purpose of more extensive Suppression of the formation of the dimers of p-Diisobutylphenolmethylol in a Dehydrated temperature below 50 ° C and at a pressure of 660 to 686 mm of mercury. After the mixture was clear at 40 ° C and a pressure of 686 mm of mercury, that is has become anhydrous under atmospheric pressure and with vigorous stirring 50 g of hydrogen bromide gas blown under the surface. The temperature of the mixture increases to 52 ° C, and there will be the formation of water as a result of the reaction of Hydrogen bromide with the methylol groups on p-diisobutylphenol according to the reaction scheme HBr + HOCH2 + HOH + BrCH2 found. Some of the methylols of p-diisobutylphenol is in 2-bromomethyl-4-diisobutylphenol and / or 2,6-di- (bromomethyl) -4-diisobutylphenol converted. The resol is immediately after the addition of hydrogen bromide by vacuum distillation partially condensed at 100 ° C and a pressure of 686 mm of mercury. The resulting Resin was removed from the flask and allowed to cool; F. (using the capillary method) 50 ° C; bound bromine 4.3%. c) bromination in the presence of water and subsequent Partial condensation A second part of the resol prepared according to a) is used in the following Wise treated: 55 g of gaseous hydrogen bromide are with vigorous stirring below the surface of 1223 g of the approximately 150% mechanically entrapped water containing resols. The temperature of the resole is before the addition of the hydrogen bromide gas 27 ° C and rises to 40 ° C by the end of the addition. 15th Minutes after the addition of the hydrogen bromide gas, mono- and dimethylol-p-diisobutylphenol is used (with partly in 2-bromomethyl-4-diisobutylphenol and / or 2,6-di- (bromomethyl) -4-diisobutylphenol converted methylols) by vacuum distillation at 95 ° C and a pressure of 686 mm of mercury is drained and thereby partially condensed to a brittle resin. This resin is removed from the flask and allowed to cool; F. (using the capillary method) 65.5 ° C; combined bromine 4.6%.

Example 3 (procedure a) a) Production of the starting resol From 1 mole of p-diisobutylphenol and 2 moles of 37% formaldehyde is used of 15% aqueous sodium hydroxide solution as a catalyst in a similar manner to that Example 2 obtained a resole.

The temperature is kept at 40 to 45 ° C until less remains than 4% free formaldehyde. The resole is then mixed with dilute hydrochloric acid neutralized to a pH of 3.5 and continued to remove the Salt and excess hydrochloric acid washed several times with water. b) bromination with gaseous Hydrogen bromide 1300 g of the resol obtained according to a) with about 15% mechanically enclosed Water becomes clear by heating to 42 ° C under a pressure of 686 mm of mercury dehydrated.

Then 200 g of benzene is added to the resole to reduce the viscosity and beneath the surface of the benzene solution of dimethylol-p-diisobutylphenol 62 g of hydrogen bromide gas blown in. The temperature of the mixture is before the addition of hydrogen bromide 40 and then 55 ° C. Stirring of the mixture is continued for an additional hour. That Dimethylol-p-diisobutylphenol with now partially to 2-bromomethyl-4-diisobutyl-6-methylolphenol and / or 2,6-di- (bromomethyl) -4-diisobutylphenol-converted methylols becomes so by vacuum distillation at 80 ° C and a pressure of 686 mm of mercury long drained until the mixture is clear. Then the resin is extracted from the flask and cooled; F. (by the capillary method) 30 ° C; bound bromine 5.8%. c) Bromination with aqueous hydrobromic acid To a second part of that prepared according to a) Resols, namely 1300 g of the approximately 15% mechanically entrapped water containing 165 g of 40% hydrobromic acid are added to dimethylol-p-diisobutylphenol. The temperature of the mixture is 27 ° C before the addition and increases after the addition to 28 ° C. The mixture is stirred for a further 2 hours and the temperature rises in the process Maintained 30 ° C. 300 g of benzene are added to facilitate water removal and dimethylol-p-diisobutylphenol, the methylol groups of which are partly in bromomethyl groups are converted, then by vacuum distillation at 80 ° C and a pressure of 686 mm of mercury dehydrated. The resin is removed from the flask and cooled ; F. (by the capillary method) 40 ° C; bound bromine 6% / z.

Example 4 (procedure a) a) Production of the starting resol A resol, namely dimethylol-p-tertiary-butylphenol, is made from a batch of p-tertiary-butylphenol ............ 1000 g formaldehyde 1080 g 18% aqueous sodium hydroxide solution 360 g prepared as follows : The p-tert-butylphenol and the sodium hydroxide solution are heated to 90 ° C. while stirring and kept at this temperature until all of the p-tertiary-butylphenol has gone into solution. The mixture is then cooled to 48 to 50 ° C and below permanently maintaining this temperature mixed with the formaldehyde. To When the addition is complete, the temperature of the mixture is raised for a further 2 hours Maintained 46 to 48 ° C until less than 4% free formaldehyde remains. Thereafter the mixture is diluted with Hydrochloric acid to a pH of 3.5 neutralized, after neutralizing the water is removed and the neutralized Mixture to remove salt and excess hydrochloric acid several times with water washed. b) bromination in the absence of water and subsequent partial condensation 500 g of the resol obtained according to a) (dimethylolp-tertiary-butylphenol) are so distilled for a long time at 55 ° C and a pressure of 686 mm mercury with stirring in a vacuum, until all mechanically entrapped water has been removed, which is cleared through of the resol noticeable. 404 g of dimethylol-p-tertiary-butylphenol are obtained. To Addition of 200 g of toluene, 28 g of hydrogen bromide gas are blown under the surface the temperature increasing to 55 ° C. The obtained dimethylol-p-tert-butylphenol, whose methylol groups are now partially converted into bromomethyl groups further dehydrated by vacuum distillation at 60 ° C and 686 mm pressure and then removed from the flask and allowed to cool.

The semi-brittle, approximately tetrameric Resitol has the following key figures : F. (according to the capillary method) 48 ° C; bound bromine 7.9 "/ o.

Example 5 (procedure a) a) Production of the starting resol A resol is made from p-tertiary amylphenol in the following way: To 1000 g of p-tertiary amylphenol are first 362 g of 18% sodium hydroxide solution and then under the regulated conditions described in Example 1, a) 790 g of 37% aqueous Formaldehyde added, with the conditions for reaction time, temperature, residual content of free formaldehyde, neutralization and washing are the same as in Example I.

The resulting resol (mono- and dimethylolp-tertiary-amylphenol) is divided into two parts. b) bromination in the presence of water and subsequent Partial condensation 700 g of the resol prepared according to a) are initially mixed with 200 g of toluene are diluted, and in this solution at 38 ° C with vigorous stirring 38 g of hydrogen bromide gas blown under the surface. Immediately after the addition of hydrogen bromide the mixture is stirred at 100 ° C and at a pressure of 686 mm of mercury distilled and then removed from the flask and cooled; F. (using the capillary method) 56 ° C; bound bromine 7.60 / o. c) bromination in the absence of water and subsequent Partial condensation A further 700 g of the resol prepared according to a) are added with stirring dehydrated by vacuum distillation at 50 ° C and a pressure of 686 mm of mercury and after becoming clear, d. H. distance of mechanically trapped water, initially diluted with 200 g of toluene. Then 30 g of hydrogen bromide gas are added with vigorous stirring blown under the surface. The temperature of the mixture is before the addition of hydrogen bromide 40 and then 62 ° C. Immediately after the addition of hydrogen bromide is complete, the mixture becomes distilled with stirring in vacuo at 95 ° C and a pressure of 686 mm of mercury. Thereafter, the reaction product is removed from the flask and cooled; F. (after the capillary method) 50 ° C; bound bromine 5%.

Example 6 (procedure c) 412 g of p-diisobutylphenol are initially with stirring with 400 g of toluene and the resulting solution with 243 g of 37% aqueous Formaldehyde added. Then 90 g of hydrogen bromide gas are added with vigorous stirring blown under the surface of the liquid at 22 ° C, increasing the temperature until the addition of hydrogen bromide is complete. Then the reaction mixture heated under reflux to 93 ° C and stirred for 3 hours in the reflux condenser Kept boiling.

Thereafter the free formaldehyde content of the aqueous layer is 160 / o. The mixture is then mercury at 100 ° C. and a pressure of 686 mm distilled and the reaction product removed from the flask and cooled.

The distillate consists of 185 cm3 of water with 10.2% free formaldehyde.

The Resitol has a melting point (according to the capillary method) of 60 ° C; bound bromine 9%.

The molecular weight corresponds to a tetrameric product.

Example 7 (procedure c) Under the same conditions as in example 6 the mixture of p-diisobutylphenol, toluene and formaldehyde is prepared. 60 g of hydrogen bromide gas are poured into this mixture under the liquid with vigorous stirring blown in. The temperature of the reaction mixture rises during the addition of hydrogen bromide gas from originally 22 to 45 ° C. The mixture is then left for 3 hours stirred at 93 ° C, and after this time there are still 7% free formaldehyde in the aqueous Layer present. The mixture is then mercury at 87 ° C and a pressure of 686 mm distilled and then removed the reaction product from the flask and cooled.

Before the start of the distillation from bromomethyl- and methylol-p-diisobutylphenol existing reaction product condensed to the tetramer during the distillation ; F. (by the capillary method) 56 ° C; bound bromine 4.55%.

The advantages of the compounds made by the process of the invention as a vulcanization accelerator compared to similar ones previously used in the art Connections result from the following comparative tests: There were Use of a butyl rubber matrix and various resinous vulcanization accelerators Approaches made and the physical data of the vulcanizates measured. The following accelerators were used: (a) one according to Example 2 of the present invention Invention produced brominated 4-alkylphenol, namely "Type SP-1055", (b) a commercially available vulcanization accelerator for butyl rubber, which consists of a composed of p-octylphenol formaldehyde resin and tin chloride (in the form of a 75% dispersion in diatomaceous earth) as an additive, and (c) that according to Example 5 of the German Patent 690,781 obtained o-bromomethyl-p-isooctylphenol.

The proportions of the mixture were each ground on a roller mill. The experimental principles and results were as follows: 8ew accelerator ABC Parts of butyl rubber, g 468 312 Parts of resin. 36 15 36 15 Parts of SnCI2 (as g ...............- 8-8 Vulcanization conditions Compression pressure, kg / cm2 105 105 105 Temperature, 145 145 Vulcanization does not occur Duration, 45 1 Tear strength ............................. 158, 4 162, 3 no vulcanization Elongation,% 66Q 67S-- Hardness (Shore A) ........................... 62 64-- Scorch (Mooney, 121GC), minutes .. 45 40 no vulcanization Evaluation When using the vulcanization accelerator according to the specification, there is no need to add a Lewis acid catalyst (SnCl2).

When using a commercially available p-octylphenol formaldehyde accelerator an economically viable vulcanization can only be achieved by adding SnCl2 reach.

The one described in Example 5 of German Patent 690,781 Bromomethylated p-isooctylphenol is neither with nor without SnCl2 as a vulcanization accelerator effective for butyl rubber.

The weakly brominated ones which can be prepared by the process of the invention 4-Alkylphenols thus offer the technical progress that they can be used without an auxiliary catalyst (SnCI2) the same high-quality vulcanizates as well-known vulcanization accelerators that require such an addition to take effect.

Claims (2)

Claims: 1. Process for the production of bromomethyl-4-alkylphenols, which may still contain methylol groups, by reacting gaseous or aqueous Hydrogen bromide with methylol compounds of 4-alkylphenols, their alkyl groups contain at least 4 carbon atoms, optionally in the presence of solvents, characterized in that either a) the 2-mono- or 2,6-dimethylol-4-alkylphenol, the alkyl radicals of which contain 4 to 20, preferably 6 to 10 carbon atoms, or b) by partial condensation of the 2-mono- or 2,6-dimethylol-4-alkylphenol obtained oligomer with an average of up to four phenol units or c) a mixture from the 4-alkylphenol with that required for the formation of the mono- or dimethylolphenol Amount of formaldehyde brominated with such an amount of hydrogen bromide that the obtained Mixture has a bromine content of about 1 to about 9%, preferably about 4 to 5% and that the resulting mixture is carried out in a manner known per se Distillation in vacuo, dehydrated and optionally in a manner known per se converted into oligomers with up to four phenol units. 2. The method according to claim 1, characterized in that the Performs bromination with those 4-alkylphenols, the alkyl radical of which is a. tertiary Butyl group, an amyl group or a diisobutyl group (di-tertiary octyl group) is. Considered publications: German Patent Specifications No. 682 138,690 781.