SK399090A3 - Method for producing tris(2,4-ditert.-butylphenyl)phosphite - Google Patents

Abstract

A process for preparing tris(2,4-di-tert-butylphenyl) phosphite from 2,4-di-tert-butylphenol and phosphorus trichloride in the presence of catalysts, characterised in that the reaction is carried out in an at least three-step process, the 2,4-di-tert-butylphenol and 40 - 100 % of the catalyst being combined in a preliminary step and brought together with the phosphorous trichloride in a first step, and being allowed to react at normal pressure and temperatures of 55 to 70 DEG C for a residence time of 15 to 40 minutes, after which the reaction mixture, in a second step, reacts at normal pressure and temperatures of above 140 DEG C, remaining amounts of catalyst of the first and/or second reaction step being added, after which the reaction mixture is kept in a third reaction step at reduced pressure at temperatures of at least 186 DEG C and the tris(2,4-di-tert-butyl-phenyl) phosphite is then isolated from the reaction mixture, the process being carried out in the absence of solvents. <IMAGE>

Description

Technical field

The invention relates to a process for the preparation of tris (2,4-di-tert-butylphenyl) phosphite from 2,4-tert-butylphenol and phosphorus trichloride in the presence of a catalyst.

BACKGROUND OF THE INVENTION

It is known from DE-A 2007070 that triaryl phosphites can be prepared from phenols and phosphorus trichloride, the reaction being carried out in three stages, carried out in three parts of the apparatus, which are in series. Said process can be carried out in the absence of any solvent, but there is excessive formation of foam in the reaction mixture, which disrupts the proper reaction.

EP-A 0000757 describes a process for producing triaryl phosphites by reacting phosphorus halides with hydroxyaromatics in the presence of catalysts. According to Example 4 of this patent EP-A 0000757 tris (2,4-di-tert-butylphenyl) phosphite can be produced by a process using a solvent. However, this use of the solvent also has the advantage that the undesired formation of foam in the reaction mixture and hence the course of the reaction can be controlled in a desirable way, and the unnoticeable disadvantage of the increased volume of the reaction mixture deterioration of space and time yield, the solvent used must be heated and cooled together with the reactants and then separated from the reaction mixture and recovered for further use, which is energy and time consuming.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It was therefore an object of the present invention to overcome the above drawbacks and to find a process which makes it possible to produce tris (2,4-di-tert-butylphenyl) phosphite in a simple manner and in high time and space yields.

The above-mentioned drawbacks substantially eliminate the process for producing tris (2,4-di-tert-butylphenyl) phosphite according to the invention, which is characterized in that the preparation of tris (2,4-di-tert-butylphenyl) phosphite is carried out in at least three stages, contacting 2,4-di-tert-butylphenol and 40 to 100% catalyst in a preliminary step, then contacting the phosphorous trichloride in the first step and reacting at normal pressure and at a temperature of 55 to 70 ° C with a residence time of 15 to 40 minutes, then the reaction mixture is reacted in the second reaction stage at normal pressure and a temperature above 140 ° C, adding the remaining amount of catalyst in the first and / or second reaction stage and maintaining the reaction mixture in the third stage tris (2,4-di-tert-butylphenyl) phosphite is isolated from the reaction mixture in the absence of a solvent.

The process according to the invention is preferably characterized in that the reaction mixture is kept in the fourth step under reduced pressure and at least 186 ° C.

The process according to the invention is preferably characterized in that the reaction time in the second step is 45 to 75 minutes.

The process according to the invention is preferably characterized in that the reaction time in the third step is 1.5 to 2.5 hours.

The process according to the invention is preferably characterized in that the reaction time in the fourth step is 20 to 120 minutes.

The process according to the invention is preferably characterized in that a temperature of 190 to 195 ° C is maintained in the fourth step.

The process according to the invention is advantageously characterized in that 2,4-di-tert-butylphenol is added in a 1- to 1.1-fold amount in terms of stoichiometry relative to phosphorus trichloride.

The process according to the invention is advantageously characterized in that the preparation of tris (2,4-di-tert-butylphenyl) phosphite is carried out in a three-stage reactor cascade.

The process according to the invention is preferably characterized in that the preparation of tris (2,4-di-tert-butylphenyl) phosphite is carried out in a four-stage reactor cascade.

The process according to the invention is preferably characterized in that the reaction mixture is stirred in at least one reaction step.

The process according to the invention is preferably characterized in that a temperature of 150 to 170 ° C is maintained in the second reaction stage.

The process according to the invention is preferably characterized in that a temperature of 190 to 195 ° C is maintained in the third reaction stage.

The process according to the invention is preferably characterized in that the third reaction stage is operated at a reduced pressure of 10 to 60 hPa.

The process according to the invention is advantageously characterized in that 50 to 100% of the amount of catalyst used and 2,4-di-tert-butylphenol are added to the reaction mixture via a packed column in which a preliminary step takes place.

The process according to the invention is preferably characterized in that the preparation of tris (2,4-di-tert-butylphenyl) phosphite is carried out continuously.

For example, the catalysts disclosed in EP-A 0000757 may be used in the process of the invention.

Examples of such catalysts are compounds from the group of amines or ammonium salts, carbonic acid or carbonic acid amides, non-aromatic nitrogen-containing heterocycles and their salts, primary, secondary and tertiary phosphines and their salts or esters of phosphoric and phosphonic acids.

Amines and ammonium salts, amides and heterocycles containing nitrogen or phosphines may optionally contain, as oxygen or sulfur atom, an interrupted alkyl group, a cycloalkyl group, an aryl group, especially a phenyl group, an alkaryl group, especially an alkylated phenyl group, an aralkyl group, especially benzyl group or an alkaralkyl group, in particular an alkylated benzyl group, which preferably has 1 to 18 carbon atoms, in particular 1 to 12 carbon atoms. The alkyl group preferably contains 1 to 6 carbon atoms, and the cycloalkyl group is preferably a cyclopentyl group and a cyclohexyl group.

The catalysts used in the form of salts are preferably halides and especially chlorides. Salts may also be formed in situ by treatment with hydrogen halide formed during the process of the invention. Also, in some cases it is preferred to use the salts themselves as catalysts.

One group of catalysts are amines and ammonium salts. These can be primary, secondary and tertiary amines, as well as their salts. Salts also include quaternary ammonium salts. Preferably, secondary amines, their salts and quaternary ammonium salts are used. Preferred are the alkyl and cycloalkyl substituted amines or ammonium salts.

Examples include:

methylamine, ethylamine, propylamine, n-butylamine, t-butylamine, pentylamine, octylamine, dodecylamine, phenylamine, benzylamine, dimethylamine, diethylamine, methylethylamine, methylbutylamine, methyloctylamine, methylphenylamine, triethymethylamine, triethylethylamine, ethylbenzylamine, triethylamine , bromide or iodide, trimethylethylammonium chloride, bromide or iodide, triethylmethylammonium chloride, bromide or iodide, tributylmethylammonium chloride, bromide or iodide, tetrabutylammonium chloride, bromide or iodide, trimethyloctylammonium chloride, bromide or iodide, bromide or iodide

Examples of other ammonium salts are:

methylammonium chloride, bromide or iodide, octylammonium chloride, bromide or iodide, dimethylammonium chloride, bromide or iodide, methylcyclohexylammonium chloride, bromide or iodide, dibenzylammonium chloride, bromide or iodide, diphenylammonium chloride, bromide or iodide bromide or iodide and triphenylammonium chloride, bromide or iodide.

The amines and ammonium salts may also contain aromatic N-heterocyclic radicals, such as a pyridyl radical. These amines are more effective than aromatic N-heterocycles alone.

Another group of catalysts includes carbonic acid amides. This group also includes ureas and their bismurea derivatives. The amides may be derived from multifunctional, preferably monofunctional, carbonic acids which preferably contain from 1 to 14 carbon atoms. These amides may also be derived from aromatic N-heterocycles. Also suitable are cyclic amides, such as ε-caprolactam. The amides derived from carbonic acids preferably correspond to the following general formula:

where n is equal to l,

R ¹ represents a phenyl group, a benzyl group, a naphthyl group, a cyclohexyl group, a cyclopentyl group, a pyridyl group, a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, or equal to 2

R ¹ represents a phenylene group, a naphthylene group, a cyclohexylene group or an alkylene group having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, or a direct bond, wherein n n ',

R and ^RJ each independently represent a hydrogen atom, a phenyl group, a benzyl group, a cyclohexyl group and an alkyl group of from 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms or R ² and R ³ together represent optionally an oxygen or sulfur atom interrupted an alkylene group preferably having 4 to 7 carbon atoms.

Examples of such compounds are formic acid amide, oxalic acid diamide, dimethylformamide, acetamide, N, N-dimethylacetamide, picolinic anilide, benzoic amide, teraphthalic diamide, melitic acid triamide. Dimethylformamide is particularly preferred as a catalyst for the process of the invention.

Examples of carbonic acid amides include, in addition to urea, tetramethylurea, diphenylurea, dibenzylurea, diethylurea, di-n-octylurea, as well as bismurea derivatives such as ethylenebismurea. Examples of cyclic ureas are hydantoin and benzimidazolone.

Another group of catalysts suitable for the process of the invention. includes non-aromatic N-heterocycles. These heterocycles may contain 1 to 3 nitrogen atoms and optionally one or 2 oxygen and sulfur atoms. These heterocycles may also be unsaturated. They may be in the form of salts and may also be in the form of quaternary ammonium bases. The nitrogen atoms may be substituted, preferably by alkyl groups having 1 to 12 carbon atoms.

Examples of these heterocycles are:

pyrrolidine _and ^3-pyrroline,

N-methylpyrrolidine, dihydroindole, pyrazolidine, imidazolidine, pyrazoline and ^2,

1-phenylpyrazolidine, oxazolidine, thiazolidine, oxazoline, triazolidine, oxadiazolidine, thiadiazolidine, piperidine, morpholine,

N-methylmorpholine, quinolidine,

1,2-dihydro-purine,

8-azabicyclo [3.2.1] octane, piperazine and

N-methylpiperazine.

Another group of catalysts useful in the process of the present invention are primary, secondary and tertiary phosphines and salts thereof. Preferred are tertiary phosphines and salts thereof, and hydrohalides, especially hydrochlorides, hydrobromides and hydroiodides, are preferred. The phosphorus atom may be optionally substituted by phenyl, benzyl, cyclohexyl and / or alkyl of 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms.

Examples of these phosphines are:

methyl phosphine, ethyl phosphine, hexylfosfίη, dodecylfosfίη, dimetylfosfίη, etylmetylfosfίη, difenylfosfίη, dicyklohexylfosfίη, dibenzylfosfίη, fenylmetylfosfίη, trifenylfosfίη, tribenzylfosfίη, tricyklohexylfosfίη, trimetylfosfίη, trietylfosfίη, tripropylfosfίη, tributylfosfίη, triizobutylfosfίη, tripentylfosfίη, trihexylfosfίη, dimetylfenylfosfίη and their hydrochloride, hydrobromide and hydroiodide.

In the case of phosphoric and phosphonic acid esters, the alcohol moieties of these esters are preferably derived from phenols and in particular C 1 -C 18 alkanols as well as from cycloalkanols, in particular, for example, phenol, 2-methylphenol, cyclohexanol, methanol, ethanol, propanol, butanol, hexanol, octanol, i-octanol, dodecanol and octadecanol. Examples of phosphonic acids are: phenyl-, benzyl-, cyclohexyl-, methyl-, ethyl-,

I propyl, butyl, pentyl and hexylphosphonic acid.

The catalyst can be used, for example, in an amount of from 0.005 to 10 mol%, preferably in an amount of from 0.05 to 8 mol%. and in particular in an amount of from 4 to 6 mol%, based on the amount of phosphorus trichloride.

The process according to the invention can be carried out in a known apparatus. Particularly preferred are reaction vessels in the form of stirrer boilers. Also useful are reaction vessels in the form of reaction columns, in particular equipped with an internal structure that forces the reactants into a rotational direction of movement, resulting in perfect mixing of the reactants.

In order to carry out the first step of the process according to the invention, it is advantageous to use a heatable reaction vessel equipped with at least two inlets, one outlet and a mixing device. Preferably, phosphorus trichloride is introduced directly into the reaction vessel through the first inlet, while 2,4-di-tert-butylphenol is introduced into the reaction vessel through a column, for example packed, through the second inlet. Depending on the nature of the catalyst, the catalyst may be partially introduced into the reactor through a third inlet. 40 to 100% of the catalyst is fed to the reaction vessel via said packed column through the second inlet of the reaction vessel. The streams of the starting materials are preferably conducted such that phosphorus trichloride is introduced into the reaction vessel through one inlet, while the catalyst and phenol compound are fed to the reaction vessel through a second inlet through a packed column.

Hydrogen chloride formed during the reaction escapes through the packed column countercurrent to the phenolic compound. The entrapped phosphorus trichloride is trapped by the phenolic compound and is thus recycled to the reaction vessel. The catalyst present in the packed column also already catalyzes the reaction and the phosphorus trichloride escaping reacts with the phenolic compound flowing through the packed column. This results in a preliminary step of the process according to the invention in the packed column. The reaction mixture then flows into the first reaction vessel.

The reactants in this reaction vessel can be thoroughly mixed with a stirrer. The reaction mixture is heated to 55-70 ° C at the same time. Preferably, the reaction mixture is heated to 60-70 ° C. The hydrogen chloride formed in the reaction is passed through a packed column. After 15 to 40 minutes, the reaction in the first step is complete. A second stage reaction can now be carried out in the first reaction vessel. Preferably, however, the contents of the first stage reaction vessel are transferred to a second reaction vessel, preferably to a heated reflux tank. The tank preferably has inlets for the reaction mixture from the first stage reaction vessel and optionally for the addition of a second portion of a given amount of catalyst, as well as a reflux condenser equipped with a hydrogen gas evacuation gas formed during the second reaction stage. Also, the second boiler tank is preferably equipped with a stirrer.

The reaction mixture is brought to a temperature above 140 ° C, for example 145 to 200 ° C, preferably 150 to 170 ° C, and particularly preferably to about 160 ° C, immediately at the start of the second stage, preferably at this temperature for 45 to 75 minutes, especially for 60 minutes. After completion of the second step, the reaction mixture is subjected to the third step either in the same reaction vessel or preferably in a further reaction vessel. The heatable reaction vessel for the third stage is preferably provided with an inlet for the reaction mixture from the second stage, an outlet for the gaseous effluents, an outlet for the reaction mixture, and a stirring device. The outlet for the escaping gaseous components, in particular for the formation of hydrogen chloride, may be equipped with a reflux condenser and optionally also with a sublimator, in order to separate the outgoing gaseous components.

Since the third stage is carried out under reduced pressure, it is necessary to take appropriate measures, i. to equip the third stage with a vacuum pump and corresponding seals and valves. Said third step of the process according to the invention is carried out at a temperature of at least 186 ° C, preferably at a temperature of 186 to 210 ° C, in particular at a temperature of 190 to 195 ° C and at reduced pressure, preferably at a pressure of 10 to 60 hPa 20 hPa, e.g. at 15 hPa. The reaction time in the third step is, for example, 1 to 2.5 hours, preferably 2 hours. After this reaction time, the reaction mixture is optionally worked up in the fourth step.

To this end, the reaction mixture is either left in the reaction vessel of the third stage or is preferably transferred to another reaction vessel, and then treated in the latter vessel, which is heatable and evacuable, under the conditions of the fourth reaction stage. Preferably, the mixture is also stirred in this fourth reaction step. Therefore, in addition to the inlet for the reaction mixture from the previous reaction stage, the reaction vessel of the fourth reaction stage must also contain a stirring device and a suitable outlet for withdrawing particularly gaseous reaction products, which is preferably equipped with a reflux condenser and a desublimator. In addition, the fourth stage reaction vessel must have an outlet for the reaction product.

Since the fourth reaction stage is also carried out under reduced pressure, the fourth stage must also be equipped with a vacuum pump and corresponding seals and valves. The reaction mixture in the fourth step is preferably worked up for 20 to 120 minutes, for example 60 minutes. During this time delay, the pressure can be maintained, for example, at 6 to 20 hPa, preferably at 10 to 15 hPa, for example at 10 hPa. The temperature in this fourth step is at least 186 ° C, preferably lies in a temperature range of 186 to 210 ° C, especially in a temperature range of 190 to 195 ° C.

In carrying out the process according to the invention, it is possible to distill off the 2,4-di-tert-butylphenol, if any, in excess, from the third-stage reaction vessel and, if necessary, from the fourth-stage reaction vessel and re-introduce the butylphenol into the process of the invention.

One preferred embodiment of the process according to the invention is that the process according to the invention is carried out in a three-stage reactor cascade.

According to a further preferred embodiment of the process according to the invention, the process according to the invention is carried out in a four-stage reactor cascade.

A further preferred embodiment of the process according to the invention consists in stirring the reaction mixture in at least one reaction step. Particularly preferably, the reaction mixture is stirred in all four stages.

In the process according to the invention it is also advantageous if the temperature in the second reaction stage is maintained in the temperature range of 170 to 190 ° C.

According to a further preferred embodiment of the process according to the invention, a temperature of 190 to 195 ° C is maintained independently of one another in the third and fourth stages.

In the process of the invention, 40 to 100% of a given amount of catalyst is added to the reaction mixture via a packed column in which the preliminary step described above takes place. Preferably, 50 to 100% of a given amount of catalyst is added to said reaction mixture via said packed column; particularly preferably 70 to 100% of a given amount of catalyst, in particular 90 to 100% of a given amount of catalyst, are added to the reaction mixture.

The remainder of the catalyst, if not all of the catalyst was added to the reaction mixture via said packed column, is added to the first and / or second reaction steps.

Preferably, the remaining amount of catalyst, if all 100% of the amount of catalyst has not been added to the reaction mixture through the packed column, is added to the first reaction stage.

Particularly preferably, the entire amount of catalyst, i. 100% catalyst, added to the reaction mixture through a packed column. All percentages given herein are percentages by weight.

The process according to the invention is particularly preferably carried out continuously.

An advantage of the process according to the invention is that tris (2,4-di-tert-butylphenyl) phosphite which is otherwise difficult to prepare can be produced in a high space and time yield. Due to the fact that the process is carried out in the absence of a solvent, more reaction volume is available, which results in higher reaction temperatures and hence higher reaction rates, reducing the time required to distill off the solvent before further processing the final product, in particular by crystallization. > OltJ: cascade reattcmy obwihw y'Urtresock; . Glycococci and these coccidians

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The four-stage stirred reactor cascade shown schematically in FIG. 1 and consisting of:

(a) Reactor A with packed column F for the first stage;

b) a main reactor B equipped with a reflux condenser K1 for the second stage;

(c) a second main reactor C equipped with a K2 reflux condenser and a downstream SI desublimator for the third stage and finally

d) an additional reactor D equipped with a reflux condenser K3 and a downstream desublimator S2;

the following streams of reactants are introduced:

Reactant 1 g / h Added to 2,4-di-tert-butyl phenol 1; content 98,9% 994 through a packed column F to reactor A Phosphorus trichloride 216.2 to reactor A Dimethylforamide 2 (catalyst) 6 through a packed column F to reactor A

(a) Reactor A conditions:

normal pressure, temperature 65 ° C, residence time 30 minutes, removal of 89.8 g / h of hydrogen chloride 4 through packed column F, removal of 1126 g / h of reaction mixture 5 through the bottom valve to the first main reactor B;

(b) conditions in the first main reactor B:

normal pressure, temperature 165 ° C, residence time 1 hour, discharge 64 g / h of hydrogen chloride 7 through reflux condenser Kl, discharge

1062.4 g / h of reaction mixture? 3 via a bottom valve to the second main reactor C;

(c) conditions in the first main reactor C:

vacuum 15 hPa, temperature 190 ° C, residence time 2 hours, discharge 13 g / h of hydrogen chloride 9 through reflux condenser K2 and desublimator

51, discharging 1049 g / h of reaction mixture 10 through a bottom valve to the additional reactor D;

(d) Additional reactor D conditions:

vacuum 10 hPa, temperature 190 ° C, residence time 60 minutes, drain

5.4 g / h of hydrogen chloride 11 via reflux condenser K3 and desublimator

52, removal of 1045 g / h of reaction mixture 12 containing 1003.2 g / h of tris (2,4-di-tert-butylphenyl) phosphite, for crystallization.

The final product obtained is of high purity and virtually no monochloro- and dichloro-compounds or unreacted phosphorus trichloride were found.

In FIG. 2 shows an alternative embodiment of the method according to the invention, which differs from the embodiment shown in FIG. 1 differs in that the reflux condenser also operates as a distillation plant in which excess 2,4-di-tert-butylphenol is separated. The 2,4-di-tert-butylphenol thus separated can be recirculated to the reaction mixture together with 2,4-di-tert-butylphenol 1.

Claims (13)

A process for the production of tris (2,4-di-tert-butylphenol) phosphite from 2,4-di-tert-butylphenol and phosphorus trichloride in the presence of a catalyst, characterized in that the preparation of tris (2,4-di-tert-butylphenyl) phosphite The reaction is carried out in at least three stages, in which the 2,4-di-tert-butylphenol and 40 to 100% catalyst are contacted in the preliminary stage, then contacted in the first stage with phosphorus trichloride and reacted at normal pressure. and a temperature of 55 to 70 ° C with a residence time of 15 to 40 minutes, after which the reaction mixture is reacted in the second reaction stage at normal pressure and a temperature above 140 ° C, adding the remaining amount of catalyst in the first and / or second reaction stage. and maintaining the reaction mixture in a third step at reduced pressure and a temperature of at least 186 ° C, then tris (2,4-di-tert-butylphenyl) phosphite is isolated from the reaction mixture, the preparation of which is carried out in the absence of a solvent. Process according to claim 1, characterized in that the reaction mixture is maintained in the fourth step under reduced pressure and a temperature of at least 186 ° C. Process according to claim 1, characterized in that the reaction time in the second step is 45 to 75 minutes. The process according to claim 1, wherein the reaction time in the third step is 1.5 to 2.5 hours. The process according to claim 2, wherein the reaction time in the fourth step is 20 to 120 minutes. Method according to claim 2, characterized in that a temperature of 190 to 195 ° C is maintained in the fourth step. The process according to claim 1, wherein 2,4-di-tert-butylphenol is added in a 1- to 1.1-fold stoichiometric amount based on phosphorus trichloride. The process according to claim 1, wherein the tris (2,4-di-tert-butylphenyl) phosphite carries out a reactor cascade. with preparation in three stages9. Process according to claim 2, characterized in that the preparation of tris (2,4-di-tert-butylphenyl) phosphite is carried out in a four-stage reactor cascade. Process according to claim 1, characterized in that the reaction mixture is stirred in at least one reaction step. Process according to claim 1, characterized in that a temperature of 150 to 170 ° C is maintained in the second reaction stage. Process according to Claim 1, characterized in that a temperature of 190 to 195 ° C is maintained in the third reaction stage. The process according to claim 1, wherein the third reaction step is operated at a reduced pressure of 10 to 60 hPa. Process according to claim 1, characterized in that 50 to 100% of the amount of catalyst used and 2,4-di-tert-butylphenol are added to the reaction mixture via a packed column in which a preliminary stage takes place. Process according to claim 1, characterized in that the preparation of tris (2,4-di-tert-butylphenyl) phosphite is carried out by a continual process.