JPH0737407B2 - Method for producing 2-chloropropionaldehyde - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to vinyl chloride, carbon monoxide and carbon monoxide according to the following reaction formula (1) CH ₂ = CHCl + CO + H ₂ → CH ₃ -CHCl-CHO (1). The present invention relates to a method for producing 2-chloropropionaldehyde using hydrogen as a raw material.

2-Chloropropionaldehyde can be used as a useful intermediate for chemicals and agricultural medicine.

(Prior art and its problems) A method for producing 2-chloropropionaldehyde using vinyl chloride, carbon monoxide and hydrogen as raw materials is known, and for example, French Patent No. 1,397,779 and HELVETICA CHIMICA ACTA. ), 48, No. 5, 11
It is shown on pages 51 to 1157. In all of these methods, cobalt carbonyl is used as a catalyst. For example, according to the above-mentioned French Patent No. 1,397,779, the reaction is carried out for 90 minutes under the conditions of a reaction temperature of 110 ° C. and a reaction pressure of 200 atm to convert vinyl chloride. The reaction results show a rate of 57.4% and a selectivity of 2-chloropropionaldehyde of 86.2%.

However, in the method using these cobalt carbonyls as catalysts, the catalytic activity per cobalt is extremely low, which requires a large amount of cobalt carbonyl and a high reaction pressure of 160 to 200 atm, and the reaction temperature is 75 to 125 ° C. The method is such that the reaction is carried out for 90 to 120 minutes under heat. The target product, 2-chloropropionaldehyde, is a thermally unstable substance. Under such a reaction temperature and reaction time, a considerable proportion is consumed in the sequential reaction and the reaction yield is lowered. The method has poor reproducibility,
Furthermore, hydrogen chloride is a by-product of this sequential reaction or other side reactions, which violently corrodes the materials of the reactor and reacts with the cobalt carbonyl catalyst to form cobalt chloride, which hinders the reuse of the catalyst. It has a problem that it brings it.

The inventors of the present invention have found that, as a method for improving these, JP-A-61-1260
As shown in No. 46, a method for reacting vinyl chloride, carbon monoxide and hydrogen in the presence of a rhodium compound and a base has already been found. This method, compared with the conventional method using cobalt carbonyl catalyst, a lower temperature and low pressure under the reaction proceeds, and although selectivity to sufficient desired product is obtained, the general formula as a base, P (R ¹ R ² R ³ ) (here,
P represents a phosphorus atom, R ¹ , R ² and R ³ are each an alkyl group,
An aryl group, a cycloalkyl group, an alkoxy group, an aryloxy group or a cycloalkoxy group), and a pyridine compound,
A combination with at least one compound selected from the group consisting of quinoline compounds, imidazole compounds and triazole compounds is particularly preferably used.

However, among these bases, all of the compounds selected from the group consisting of pyridine compounds, quinoline compounds, imidazole compounds and triazole compounds are relatively expensive compounds, so the loss amount is industrially used. It is necessary to install these recovery devices to minimize the number. Further, since all of these are highly reactive compounds, they are gradually consumed when used for a long time. Therefore, the operation also needs to be carried out so as to suppress these losses as much as possible, but the operating conditions are not always in agreement with the conditions advantageous for the synthesis of 2-chloropropionaldehyde. Therefore, there is a problem in that the consumption and the reaction at a place slightly out of the optimum synthesis conditions have a considerable influence on the production cost of the target product, 2-chloropropionaldehyde.

An object of the present invention is to provide a method for producing 2-chloropyropionaldehyde which solves the above-mentioned problems of the prior art.

(Means for Solving Problems) The present inventors have conducted detailed research for solving these problems. As a result, vinyl chloride, carbon monoxide and hydrogen are reacted in the presence of a rhodium compound and a base to give 2
-In producing chloropropionaldehyde, it is efficient to use a combination of a trivalent organophosphorus compound or an oxide of a trivalent organophosphorus compound as a base and an oxide, hydroxide or weak acid salt of an alkali metal or an alkaline earth metal. The present invention has been accomplished by finding that the problems of the catalyst composed of rhodium and a base as described above can be solved in addition to the progress of the reaction well.

That is, according to the present invention, vinyl chloride, carbon monoxide and hydrogen are reacted in the presence of a rhodium compound and a base to produce 2
-In the production of chloropropionaldehyde, at least one trivalent organic phosphorus compound or at least one oxide of a trivalent organic phosphorus compound as a base, and at least one alkali metal or alkaline earth metal oxide, hydroxide or weak acid salt. And a method of producing 2-chloropropionaldehyde.

The bases preferably used in the method of the present invention are exemplified as follows.

That is, as the trivalent organic phosphorus compound, a compound represented by the general formula P (R ¹ R
² R ³ ) (wherein P represents a phosphorus atom, and R ¹ , R ² and R ³ each represent an alkyl group, an aryl group, a cycloalkyl group, an alkoxy group, an aryloxy group or a cycloalkoxy group) Trivalent organophosphorus compounds are included,
Specifically, phosphines such as trimethylphosphine, triethylphosphine, tripropylphosphine, tributylphosphine, trioctylphosphine, triphenylphosphine, tricyclohexylphosphine, and tribenzylphosphine, trimethylphosphite, triethylphosphite, and tripropylphosphine. Examples thereof include phosphites such as phyto, tributyl phosphite, trioctyl phosphite, triphenyl phosphite, tricyclohexyl phosphite, and tribenzyl phosphite.

As a special kind of phosphine, the above general formula P
In addition to those represented by (R ¹ R ² R ³ ), diphosphines such as bisdiphenylphosphinomethane and bisdiphenylphosphinoethane, and phosphines bonded to crosslinked polystyrene are also preferably used.

Further, as an oxide of a trivalent organic phosphorus compound, an alkylphosphine oxide such as triethylphosphine oxide, tributylphosphine oxide or trioctylphosphine oxide, an arylphosphine oxide such as triphenylphosphine oxide or tritolylphosphine oxide, or an alkyl group and an aryl Examples thereof include alkylarylphosphine oxide having a group. In addition, triethyl phosphite oxide, tributyl phosphite oxide,
Alkyl or aryl phosphite oxides such as triphenyl phosphite oxide, and alkylaryl phosphite oxides having both an alkyl group and an aryl group can also be used. Moreover,
Oxides of polydentate phosphines such as bis-1,2-diphenylphosphinomethanedioxide can also be used.

Also, alkali metal or alkaline earth metal oxides,
The hydroxide or weak acid salt is specifically exemplified as follows. That is, examples of alkali metal or alkaline earth metal oxides include sodium oxide, potassium oxide, calcium oxide, barium oxide, and the like, and alkali metal or alkaline earth metal hydroxides include sodium hydroxide and potassium hydroxide. Examples include calcium hydroxide and barium hydroxide.

Further, as weak acid salts of alkali metals or alkaline earth metals, carbonates or hydrogen carbonates such as sodium carbonate, potassium carbonate, calcium hydrogen carbonate, sodium acetate, potassium acetate, calcium acetate, sodium formate,
Carboxylic acid salts such as potassium formate, sodium propionate, sodium benzoate, potassium citrate, sodium ascorbate, sodium monochloroacetate, sodium dichloroacetate, etc. can be mentioned. In addition, it shows alkalinity in water such as trisodium phosphate. Alkali metal or alkaline earth metal compounds are also included in the preferred bases in the process of the invention.

Examples of the rhodium compound used in the method of the present invention include rhodium oxide, mineral acid salt, organic acid salt, and rhodium complex compound. Among these various rhodium compounds, a halogen-free rhodium compound is particularly preferable. Examples of these are rhodium oxide, rhodium nitrate,
Rhodium nitrate, rhodium acetate, triacetylacetonato rhodium, dicarbonyl acetyl acetonato rhodium, dodecacarbonyl tetrarhodium, hexadecacarbonyl hexarhodium, etc. are mentioned. Those in which a complex compound is formed with a base are more preferably used.
The base may be a base preferably used in the method of the present invention, but may be another base. Examples of these include hydridocarbonyl tristriphenylphosphine rhodium [RhH (CO) (PP
h _{3) 3],} nitro silt list Li triphenylphosphine rhodium _{[Rh (NO) (PPPh 3)} 3 ], .eta. cyclopentadienyl bis triphenylphosphine rhodium [Rh (C ₅ H ₅
(PPh ₃ ) ₂ ] and the like.

Further, using a halogen-containing rhodium compound such as rhodium chloride, rhodium bromide, rhodium iodide or dichlorotetracarbonyl dirhodium, an alkaline compound in an amount equal to or more than these halogen atoms in the reaction system, for example, sodium hydroxide, Addition of potassium hydroxide, potassium carbonate, trimethylamine, triethylamine or the like can also be used as a means for producing a halogen-free rhodium compound in the reaction system.

In the method of the present invention, the rhodium compound has a content of 0.0001 to 10 as rhodium atom per 1 liter of liquid phase in the reaction system.
It is used in an amount corresponding to 00 milligram atoms, preferably in the range 0.001 to 100 milligram atoms. The base used in the method of the present invention is used in an amount of 0.1 to 500 mol, preferably 0.5 to 100 mol, per 1 gram atom of rhodium.

In the method of the present invention, the reaction proceeds without using a reaction solvent, but the reaction is usually performed in the presence of the reaction solvent. Any reaction solvent can be used as long as it does not adversely affect the reaction. Hydrocarbons are particularly preferable as such a solvent. More specifically, hexane, heptane, octane, nonane, saturated hydrocarbons such as decane, benzene, toluene, aromatic hydrocarbons such as xylene are preferably used, and
Ligroin, kerosene, light oil, diesel oil and the like which are industrially obtained as a mixture of hydrocarbons are also included in these examples. In addition, ethers such as dipropyl ether and dibutyl ether, ketones such as diisobutyl ketone and holone, and esters such as butyl butyrate and butyl benzoate are also mentioned as examples of preferable solvents.

In the method of the present invention, a method in which water coexists in the reaction system is more preferably performed. By taking such a method, the catalytic activity is further improved.

In the method of the present invention, the amount of water to be present during the reaction is not particularly limited, but when the amount is extremely small, the effect is small, and even when the amount is extremely large, the reaction result does not increase to some extent. Usually, the amount of water is 0.01 or more by weight ratio to vinyl chloride supplied to the reactor as a raw material,
A range of 1000 or less is preferable. Particularly, the range of 0.1 to 100 is more preferably used.

In carrying out the method of the present invention, other components in the reaction system, such as additives for improving the stability of the rhodium catalyst, additives for improving the activity and selectivity of the catalyst, such as carboxylic acid Even if they coexist, there is no particular problem.

The method of the present invention is usually carried out at a reaction temperature of 10 to 150 ° C. and a reaction pressure of 1
0-300 Kg / cm ² gauge range, preferably 30-150 Kg / cm ²
It is done in the gauge range. The reaction temperature is preferably as low as possible from the viewpoint of the thermal stability of the produced 2-chloropropionaldehyde, and for this reason, 20-80 ° C is a particularly preferred temperature range. The mixing molar ratio of the raw material carbon monoxide and hydrogen is usually in the range of 10 to 0.1, preferably in the range of 4 to 0.2. Carbon monoxide and hydrogen may be a mixed gas containing both components in the above composition ratio, and water gas, or a gas such as methane, a gas inert to the reaction such as nitrogen, or carbon dioxide was contained. Things are used. The other raw material, vinyl chloride, is used in the form of gas, liquid, or solution dissolved in the solvent used for the reaction.

The method of the present invention can be carried out by any of a batch method, a semi-batch method and a continuous method. For example, in the case of the batch method, vinyl chloride is added as a gas, liquid or solution to an autoclave charged with a rhodium compound, a base and optionally a reaction solvent, and water, to which carbon monoxide and hydrogen are added. The reaction proceeds by introducing a gas containing the above to a predetermined pressure, and preferably by heating under stirring. Further, as an example of the continuous method, a rhodium compound, a base and optionally a reaction solvent and water, and raw materials vinyl chloride, carbon monoxide and hydrogen are continuously supplied to one of the pressure resistant reactors. Then, the reaction is carried out by continuously withdrawing the reaction mixture, unreacted vinyl chloride, carbon monoxide and hydrogen from the other under the stirring conditions at the reaction temperature.

(Operation and Effect of the Invention) According to the present invention, 2-chloropropionaldehyde can be produced in high yield at low temperature and low pressure using vinyl chloride, carbon monoxide and hydrogen as raw materials. In particular, according to the method of the present invention, it is possible to stably use a simple apparatus for a long time without requiring an apparatus for recovering the base or selecting conditions for suppressing the loss of the base as much as in the conventional method. The reaction can proceed.

(Examples) Hereinafter, the method of the present invention will be described more specifically with reference to Examples.

Example 1 After the inside of a stainless steel autoclave with an internal volume of 100 ml equipped with a stirrer was replaced with nitrogen gas, hexadecacarbonylhexalhodium 36 mg (Rh 0.2 mg atom), triphenylphosphine 157 mg (0.6 mmol), sodium acetate 82 mg (1 mmol) and 20 g of water were added, and 20 m of a vinyl chloride toluene solution containing 3.75 g (60 mmol) of vinyl chloride was added thereto. A gas mixture of carbon monoxide and hydrogen in a molar ratio of 1: 2 was injected into the autoclave at room temperature until the pressure reached 80 kg / cm ² gauge, then the temperature was raised to 60 ° C., and the reaction was carried out for 20 minutes. After cooling the autoclave to room temperature, the unreacted raw material mixed gas was collected in a gas sampling bag, the autoclave was opened, and the reaction mixed solution containing the catalyst, the solvent and the reaction product was taken out. As a result of quantifying the gas and the liquid by gas chromatography, the conversion rate of vinyl chloride was 12.6%, and the production amount of 2-chloropropionaldehyde was 6.6 mmol (selectivity based on the converted vinyl chloride was 87.3%).

Examples 2 to 6 In the method of Example 1, the reaction was carried out by changing the reaction temperature, the reaction pressure, the carbon monoxide / hydrogen molar ratio and the reaction time. The results are shown in Table 1.

Examples 7 to 12 In the method of Example 1, the reaction temperature was set to 55 ° C, and the types of rhodium compound and base were changed to carry out the reaction. The amount of the rhodium compound was set to such an amount that rhodium was 0.2 mg atom. The results are shown in Table 2.

Example 12 The reaction was performed in the same manner as in Example 1 except that water was not used.

As a result of the analysis, a reaction result was obtained in which the conversion rate of vinyl chloride was 4.3% and the selectivity of 2-chloropropionaldehyde was 88.7%.

Claims (3)

[Claims] 1. A trivalent organic phosphorus compound or a trivalent organic compound is used as a base for producing 2-chloropropionaldehyde by reacting vinyl chloride, carbon monoxide and hydrogen in the presence of a rhodium compound and a base. A method for producing 2-chloropropionaldehyde, which comprises using at least one oxide of a phosphorus compound and at least one oxide, hydroxide or weak acid salt of an alkali metal or an alkaline earth metal. 2. The method according to claim 1, wherein the reaction is carried out in the presence of water. 3. The method according to claim 1, wherein the reaction temperature is in the range of 20 to 80 ° C.