JPH0720905B2 - Method for producing 2-chloropropionaldehyde - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to vinyl chloride, carbon monoxide and hydrogen 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 as a raw material.
2-Chloropropionaldehyde can be used as a useful intermediate for chemicals and agricultural medicine.

(Prior Art) A method for producing 2-chloropropionaldehyde using vinyl chloride, carbon monoxide and hydrogen as a raw material is known, and for example, French Patent No. 1,397,779 and HELVETICA CHIMICA ACTA, 48 volumes. , No. 5, 11
It is shown on pages 51 to 1157. These methods all use cobalt carbonyl as a catalyst, for example, according to the above-mentioned French Patent No. 1,397,779, a reaction temperature of 110 ° C.,
The reaction was performed under a reaction pressure of 200 atm for 90 minutes, and the reaction results were 57.4% conversion of vinyl chloride and 86.2% selectivity of 2-chloropropionaldehyde.

(Problems to be solved by the invention) However, in the method using these cobalt carbonyls as a catalyst, the catalytic activity per cobalt is extremely low,
For this reason, a large amount of cobalt carbonyl and a high reaction pressure of 160 to 200 atm are required, 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, and under such a reaction temperature and reaction time, a considerable proportion is consumed in the sequential reaction, so that the reaction yield is lowered. , This method is not reproducible, and hydrogen chloride is by-produced by this sequential reaction or other side reaction, which violently corrodes the material of the reactor and reacts with the cobalt carbonyl catalyst to form cobalt chloride. In addition, there is a problem in that the reuse of the catalyst is also hindered.

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

(Means for Solving Problems) The present inventors have conducted detailed research for solving these problems. As a result, when vinyl chloride, carbon monoxide and hydrogen are reacted in the presence of a rhodium compound, a base and a carboxylic acid, the reaction proceeds at a lower temperature and lower pressure than the conventional method using a cobalt carbonyl catalyst. , And found that sufficient selectivity to the desired product is obtained,
This led to the present invention.

That is, the present invention is a method for producing 2-chloropropionaldehyde, which comprises reacting vinyl chloride, carbon monoxide and hydrogen in the presence of a rhodium compound, a base and a carboxylic acid.

In the method of the present invention, it is important to use a catalyst in which a rhodium compound is combined with a base and a carboxylic acid in the reaction system.

The base described here generally means a Lewis base containing a periodic VB group element such as nitrogen, phosphorus, or arsenic. In the absence of these bases, rhodium compounds do not catalyze the above reaction at all. Preferred as the base used in the method of the present invention is a trivalent organic phosphorus compound or an oxide of a trivalent organic phosphorus compound, or a nitrogen-containing compound having a pKa in the range of 3 to 11.
In particular, it is more preferable that the base is a combination of a trivalent organic phosphorus compound or an oxide of a trivalent organic phosphorus compound and a nitrogen-containing compound having a pKa in the range of 3 to 11.

The trivalent organophosphorus compound described here is 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 represent the same or different alkyl, aryl, cycloalkyl, alkoxy, aryloxy or cycloalkoxy groups) A representative trivalent organophosphorus compound, and specific examples include phosphines such as trimethylphosphine, triethylphosphine, tripropylphosphine, tributylphosphine, trioctylphosphine, triphenylphosphine, tricyclohexylphosphine, and tribenzylphosphine. And trimethyl phosphite, triethyl phosphite, tripropyl phosphite, tributyl phosphite, trioctyl phosphite, triphenyl phosphite, tricyclohexyl phosphite, tribenzyl phosphite, etc. Examples include phosphites. 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, the oxide of a trivalent organic phosphorus compound refers to an oxide corresponding to the above-mentioned trivalent organic phosphorus compound, and specific examples thereof include triethylphosphine oxide, tributylphosphine oxide, trioctylphosphine oxide and the like. Examples thereof include arylphosphine oxides such as alkylphosphine oxide, triphenylphosphine oxide and tritolylphosphine oxide, and alkylarylphosphine oxides having an alkyl group and an aryl group in combination. In addition to this,
Examples thereof also include alkyl or aryl phosphite oxides such as triethyl phosphite oxide, tributyl phosphite oxide, and triphenyl phosphite oxide, and alkylaryl phosphite oxides having both an alkyl group and an aryl group. Furthermore, oxides of polydentate phosphines such as bis-1,2-diphenylphosphinomethanedioxide are also included in these examples.

On the other hand, as amines having a pKa in the range of 3 to 11, compounds having an amino group, such as aliphatic amines, aromatic amines, diamines, triamines, amino alcohols, are generally used. Amino acids, amides, urea compounds, guanidines, amidines, or nitrogen-containing compounds in which a nitrogen atom or a carbon atom of these compounds has a substituent such as an alkyl group, an aryl group, a carboxyl group, a hydroxyl group or a halogen. In the pK
Examples thereof include compounds in which a is in the range of 3 to 11. In addition, among other heterocyclic compounds containing more than nitrogen-atoms, pK
A compound in which a is in the range of 3 to 11 is also preferable. Above all, pKa
Is more preferably at least one of a pyridine compound, a quinoline compound, an imidazole compound, and a morpholine compound in the range of 3 to 11.

A pyridine compound having a pKa in the range of 3 to 11,
The quinoline compound, the imidazole compound, or the morpholine compound is exemplified as follows.

That is, the pyridine compound has the general formula (In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁵ are each hydrogen,
A compound represented by an alkyl group, an aryl group, a cycloalkyl group, a halogen, a hydroxyl group, an alkoxy group, an aryloxy group, a cycloalkoxy group, a carboxy group or an acetyl group) having a pKa in the range of 3 to 11 There are compounds, examples of which are pyridine, picoline, ethylpyridine, 2,4-lutidine, α-
Examples include collidine, phenylpyridine, cyclohexylpyridine, benzylpyridine, 3-pyridinol, methoxypyridine, phenoxypyridine, and aminopyridine. In addition, polynuclear pyridines such as 2,2'-bispyridine are also mentioned as an example of the pyridine compound.

In addition to quinoline, examples of quinoline compounds include 2-
There are methylquinoline, 4-methylquinoline, dimethylquinoline, 2-ethylquinoline, phenylquinoline, methoxyquinoline and the like, and various isoquinoline compounds can also be used.

On the other hand, the imidazole compound has the general formula (In the formula, R ¹ , R ² , R ³ and R ⁴ each represent hydrogen, an alkyl group, an aryl group or a cycloalkyl group, and
R ³ and R ⁴ may form a condensed imidazole which forms a ring containing carbons at positions 4 and 5 of the imidazole ring), and some have a pKa in the range of 3 to 11 , Examples of these include imidazole, N-methylimidazole, N-ethylimidazole, 2-methylimidazole, 22-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, N-benzyl-
2-Methylimidazole, 2,4,5-triphenylimidazole, benzimidazole, 2-methylbenzimidazole, 2-phenylbenzimidazole and the like can be mentioned.

Furthermore, examples of the morpholine compound include N-methylmorpholine, N-ethylmorpholine, and the like, in addition to morpholine.

In the method of the present invention, as the carboxylic acid, an aliphatic or aromatic monovalent or polyvalent carboxylic acid is used, and one having a pKa in an aqueous solution of 1.5 to 5.0 is more preferable. Further, if the pKa in the aqueous solution is within this range, the carboxylic acid may contain various substituents. Examples of these substituents include halogen, amino group, aryl group, hydroxyl group or nitro group. Further, the aliphatic carboxylic acid may be saturated or unsaturated. Specifically, acetic acid, propionic acid, butyric acid, aliphatic saturated monocarboxylic acids such as valeric acid, acrylic acid, aliphatic unsaturated monocarboxylic acids such as crotonic acid,
Examples thereof include aliphatic polycarboxylic acids such as adipic acid, citric acid and succinic acid, and aromatic mono- or polycarboxylic acids such as benzoic acid, o-phthalic acid, p-phthalic acid and 1-naphthoic acid.
Further, examples of the carboxylic acid having a substituent include monofluoroacetic acid, 2-chloropropionic acid, o-fluorobenzoic acid, lactic acid, phenylacetic acid and the like. Among these carboxylic acids, o-phthalic acid is particularly preferably used.

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 include rhodium oxide, rhodium nitrate, rhodium sulfate, rhodium acetate, triacetylacetonato rhodium, dicarbonylacetylacetonato rhodium, dodecacarbonyl tetrarhodium, hexadecacarbonyl hexarhodium 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 equivalent amount or more to 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. Further, in the method of the present invention, as the rhodium compound, a compound in which a rhodium compound and at least a part of these bases form a complex compound is more preferably used. Examples of these include hydridocarbonyltristriphenylphosphine rhodium [RhH (CO) (PPh ₃ ) ₃ ], nitrosyltristriphenylphosphine rhodium [Rh (NO) (PP
h ₃ ) ₃ ], η-cyclopentadienylbistriphenylphosphine rhodium [Rh (C ₅ H ₅ ) (PPh ₃ ) ₂ ] and the like. In the method of the present invention, the rhodium compound is
As rhodium atom per 1 liter of liquid phase in the reaction system,
0.0001-1000 mg atom, preferably 0.001-100
Used in amounts equivalent to the milligram atom range. The base used in the method of the present invention is used in an amount of 0.1 to 50 mol, preferably 0.5 to 100 mol, per 1 gram atom of rhodium. On the other hand, although the amount of the carboxylic acid used in the method of the present invention depends on the kind of the carboxylic acid, it is usually 1 gram atom of rhodium.
It is used in the range of -200 mol, preferably 5-50 mol.

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 and aromatic hydrocarbons such as benzene, toluene and xylene are preferably used, and ligroin, kerosene, gas oil, diesel oil and the like which are industrially obtained as a mixture of hydrocarbons are also used. Included in the example. In addition to these, 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 exemplified as preferable solvents.

In the method of the present invention, the reaction proceeds even in the absence of water, but the reaction is preferably performed in the presence of water.
The presence of water improves the catalytic activity. In the method of the present invention,
A method in which a liquid medium insoluble or slightly soluble in water is used as a reaction solvent and water is allowed to coexist in the reaction system is more preferable. By taking such a method, the catalytic activity is further improved. The amount of water to be present during the reaction in the method of the present invention is not particularly limited, but in the case of an extremely small amount,
The effect is small, and the reaction results do not improve beyond a certain level even if used in an extremely large amount. Usually, the amount of water is 0 by weight with respect to vinyl chloride supplied to the reactor as a raw material.
The range of 01 or more and 1000 or less is preferable. Particularly, the range of 0.1 to 100 is more preferably used.

When the base or carboxylic acid used in the present invention is water-soluble, it is also preferably carried out by dissolving at least a part of the base or carboxylic acid in water to be supplied to the reaction system. For example, when imidazole is used as the base, it is preferably supplied to the reactor in the form of an imidazole aqueous solution, and as carboxylic acid, o-
When phthalic acid is used, it is preferably fed to the reactor in the form of o-phthalic acid aqueous solution. It is also possible to use it in the form of an aqueous solution in which both a base and a carboxylic acid are dissolved.

The method of the present invention is usually carried out at a reaction temperature of 20 to 150 ° C and a reaction pressure of
0-200 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 2-chloropropionaldehyde produced, and therefore, 20-100 ° C is a particularly preferred temperature range. The mixing molar ratio of carbon monoxide and hydrogen of the raw materials is usually in the range of 10 to 0.1, preferably 4 to
It is in the range of 0.2. Carbon monoxide and hydrogen may be any mixed gas containing both components in the above composition ratio, and water gas, 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 a gas, a liquid, or a solution dissolved in a 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 to an autoclave charged with a rhodium compound, a base, a carboxylic acid, and optionally a reaction solvent and water in a gas, liquid, or solution form, and then monooxidized. The reaction proceeds by introducing a gas containing carbon and hydrogen up to a predetermined pressure, and preferably heating with stirring. As an example of the continuous method, a rhodium compound, a base, a carboxylic acid, 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. Reaction is carried out by continuously withdrawing unreacted vinyl chloride, carbon monoxide, and hydrogen from the other side.

(Operation and Effect of the Invention) According to the present invention, 2-chloropropionaldehyde can be produced in high yield at a lower temperature and a lower pressure using vinyl chloride, carbon monoxide and hydrogen as raw materials. In particular,
By the method of the present invention, higher catalytic activity and 2-
It is possible to proceed the reaction under the selectivity to chloropropionaldehyde.

(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, hydridocarbonyltristriphenylphosphine rhodium 184 mg (Rh
0.2 mg atom) and triphenylphosphine 262 mg
(1 mmol), 510 mg of imidazole (7.5 mmol),
640 mg (4 mmol) of o-phthalic acid and 20 g of water were added, and to this was added 20 ml of a toluene solution of vinyl chloride containing 3.75 g (45 mmol) of vinyl chloride. In this autoclave,
A mixed gas of carbon monoxide and hydrogen in a molar ratio of 1: 2 was injected at room temperature until the pressure reached 75 kg / cm ² gauge, then the temperature was raised to 50 ° C., and the reaction was performed for 60 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 liquid by gas chromatography, the conversion rate of vinyl chloride was 22.5%, the production amount of 2-chloropropionaldehyde was 12.9 mmol (selectivity based on the converted vinyl chloride was 95.6%). It was confirmed that propionaldehyde was produced as a by-product with a selectivity of 1.7%.

Examples 2 to 7 In the method of Example 1, the reaction was performed by changing the reaction temperature, the reaction pressure, the molar ratio of carbon monoxide and hydrogen, and the reaction time. The results are shown in Table 1.

Examples 8 to 11 In the method of Example 1, the reaction temperature was 60 ° C and the reaction time was
The reaction was carried out for 30 minutes by changing the amount and type of the rhodium compound and the base. 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.

Examples 12 to 15 By the method of Example 1, the reaction was carried out by changing the kind and amount of the carboxylic acid. The results are shown in Table 3.

Example 16 The reaction was performed in the same manner as in Example 1 except that triphenylphosphine and water were not present.

As a result of the analysis, the reaction results of vinyl chloride conversion 14.7% and 2-chloropropionaldehyde selectivity 92.8% were obtained.

Claims (8)

[Claims] 1. A process for producing 2-chloropropionaldehyde, which comprises reacting vinyl chloride, carbon monoxide and hydrogen in the presence of a rhodium compound, a base and a carboxylic acid. 2. The method according to claim 1, wherein the base is a trivalent organic phosphorus compound or an oxide of a trivalent organic phosphorus compound. 3. The method according to claim 1, wherein the base is a nitrogen-containing compound having a pKa in the range of 3-11. 4. A pK containing at least one trivalent organic phosphorus compound or at least one oxide of a trivalent organic phosphorus compound as a base.
The method according to claim 1, wherein a is a combination with at least one nitrogen-containing compound in the range of 3 to 11. 5. A nitrogen-containing compound having a pKa in the range of 3 to 11 is at least one of a pyridine compound, a quinoline compound, an imidazole compound and a morpholine compound having a pKa in the range of 3 to 11. The method according to item 3 or 4. 6. The carboxylic acid has a pKa in an aqueous solution of 1.5 to 5.
Claims 1 to 5 which are carboxylic acids of 0
Method described in section. 7. The method according to any one of claims 1 to 6, wherein water coexists in the reaction system. 8. The method according to claim 1, wherein a liquid medium insoluble or hardly soluble in water is used as a reaction solvent, and water is allowed to coexist in the reaction system.