JPH0550492B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing cinnamic acid esters by reacting styrenes, carbon monoxide, alcohol and oxygen. Cinnamic acid esters are widely used as fragrances or raw materials thereof due to their aromatic properties, and are also important compounds as raw materials for agricultural chemicals and photosensitive resins. (Prior Art) Cinnamic acid has conventionally been produced on a small scale by a reaction using benzaldehyde and acetic acid derivatives as main raw materials. However, since this method uses expensive raw materials, it is not an industrially preferred method. As a method using cheaper raw materials, several methods have been proposed in which cinnamic acid esters are produced by reacting styrenes with carbon monoxide, alcohol, and oxygen in the presence of a catalyst (for example, 1984-15242, JP-A-56-22749, JP-A-56-
22750, JP 56-71039, JP 57-21342, JP 57-21343, JP 57-70836, JP 60-
92242, JP 60-92243, JP 60-94940, JP 60-97935, etc.). (Problems to be Solved by the Invention) However, these methods have not yet been industrialized because the catalyst activity is still low and the reaction results are not satisfactory. An object of the present invention is to provide a method for producing cinnamic acid esters with high catalytic activity and high reaction performance by reacting styrenes and alcohols with low partial pressures of carbon monoxide and oxygen. (Means for Solving the Problems) In order to achieve the above object, the inventors of the present invention have continued to study intensively, and first (1) conventional techniques, for example, Japanese Patent Laid-Open No. 57
As shown in many examples in Publication No. 70836 and No. 56-15242, when only cupric chloride is used as a donor compound for copper and chlorine as co-catalysts, the amount of copper atoms used is If an attempt is made to select a preferable range, the amount of chlorine atoms to be used is thereby limited, and a preferable range cannot be selected arbitrarily, and this is one of the reasons why the catalyst system is not industrially satisfactory. (2) Copper and chlorine are important as co-catalysts when producing corresponding cinnamic acid esters by reacting carbon monoxide, alcohol and oxygen with palladium metal or its compounds as the main catalyst. and the need for each of these sources to be separate or at least partially separate compounds and for the amounts used of each to be selected within a specific range, i.e. palladium metal or its compound as the main catalyst and the auxiliary. As a catalyst, (1) an organic acid salt of copper, (2) a chlorine compound, and (3) a compound of manganese or zinc are used, the amount of copper atoms per liter of reaction mixture is set in a specific range, and the amount of copper atoms of chlorine atoms is set to a specific range. We have already filed an application after discovering that by setting the gram atomic ratio to a specific range, high activity of the main catalyst can be obtained and cinnamic acid esters can be produced with high reaction results. Subsequently, we continued to study this reaction, and found that the main catalyst and co-catalyst identified above and the reaction range in which they are used showed high activity of the main catalyst even under low partial pressures of carbon monoxide and oxygen, resulting in high reaction results. discovered that cinnamic acid esters could be produced using
The invention has been completed. That is, the present invention uses palladium metal or its compound as the main catalyst and (1) copper organic Using an acid salt, (2) a chlorine compound, and (3) a manganese or zinc compound, the copper atom in the reaction mixture is 0.004 to 0.4 gram atom/and the chlorine atom to copper atom ratio is less than 2. , a method for producing cinnamic acid esters, further comprising carrying out the reaction at a partial pressure of carbon monoxide of 1 atm or less and a partial pressure of oxygen of 1 atm or less. Specifically, the styrenes used in the method of the present invention include styrene, α-methylstyrene, β-methylstyrene, α-ethylstyrene, β-ethylstyrene, o-methylstyrene,
m-methylstyrene, p-methylstyrene, m-
Reaction of alkyl derivatives of styrene such as ethylstyrene, p-ethylstyrene, p-tert-butylstyrene, β-methyl-p-isopropylstyrene, or p-chlorostyrene, p-methoxystyrene, 3,4-dimethoxystyrene, etc. Examples include styrene derivatives having a substituent on the aromatic ring that does not inhibit Alcohols include methanol, ethanol, propanol, butanol, pentanol,
Alcohols such as octanol, cyclopentanol, cyclohexanol, phenol, benzyl alcohol, ethylene glycol, polyethylene glycol, and propylene glycol, which may have substituents such as halogen or alkoxy groups that do not inhibit the reaction. . The amount of these alcohols used is 1 mole of styrene.
~100 mole parts, and may be used not only as a reaction raw material but also as a solvent. The carbon monoxide and oxygen used in the method of the present invention are preferably diluted with an inert gas such as nitrogen or argon in order to avoid explosion.
Air can also be used as the oxygen source. The partial pressure of carbon monoxide carried out in the method of the invention is:
The absolute pressure is less than 1 atmosphere. Preferably 0.005~
It is in the range of 1 atm. Further, the partial pressure of oxygen is 1 atm or less, preferably in the range of 0.002 to 1 atm. Using carbon monoxide and oxygen at these low partial pressures, even when diluted with inert gas, results in a low total pressure of carbon monoxide, oxygen and inert gas in the reactor, making it extremely industrially preferable. These carbon monoxide, oxygen, and inert gases may be charged into the reactor in the required amounts all at once, or by adding the necessary gases continuously or intermittently, or by adding a mixture of these gases continuously or intermittently. It may also be possible to distribute the information publicly. Among these methods, the method of adding or the method of distributing is more preferable. During the reaction, it is preferable to stir sufficiently in order to improve gas-liquid contact. In the reaction according to the method of the present invention, the alcohol as a raw material can essentially be used as a solvent, but any solvent can also be used as long as it does not inhibit the reaction. Examples of such solvents include ethers such as diethyl ether, dipropyl ether, methyl ethyl ether, phenylethyl ether, diphenyl ether, tetrahydrofuran, dioxane, ethylene glycol diethyl ether, and tetraethylene glycol dimethyl ether, acetone, methyl ethyl ketone, and acetophenone. Ketones such as, esters such as methyl acetate, ethyl acetate, methyl propionate, benzene, toluene,
Aromatic hydrocarbons or substituted compounds thereof such as p-xylene, ethylbenzene, chlorobenzene, dichlorobenzene, aliphatic or alicyclic hydrocarbons such as n-hexane, n-pentane, cyclohexane, propylene carbonate, dimethyl carbonate, etc. carbonates, nitriles such as acetonitrile and benzonitrile, nitro compounds such as nitrobenzene and nitromethane, amide compounds such as dimethylformamide, and sulfolane compounds such as sulfolane. The main catalyst of the present invention is palladium metal or its compound, such as palladium black, metal palladium supported on a carrier such as activated carbon, asbestos, or silica alumina, dibenzylideneacetone complex, or tetrakis(triphenylphosphine)palladium. Zero-valent palladium metals or compounds such as zero-valent palladium complexes, inorganic acid salts of palladium such as palladium chloride, palladium nitrate, organic acid salts of palladium such as palladium acetate or palladium benzoate, bis(acetylacetonato)palladium, cyclo Examples include divalent palladium compounds such as palladium complexes such as octadiene dichloropalladium, palladium chloride benzonitrile complex, palladium chloride pyridine complex, or palladium chloride ammine complex. The amount of palladium metal or its compound used is in the range of 0.000001 to 0.1 gram atom, preferably 0.000005 to 0.01 gram atom, per mole of styrene as a raw material. Cocatalysts in the process of the invention are organic acid salts of copper, chlorine compounds and compounds of manganese or zinc. The organic acid salts of copper, which are the first component, include aliphatic copper carboxylates such as copper acetate, copper propionate, and copper stearate, aromatic copper carboxylates such as benzoate, and copper acetylacetate. Examples include salts of organic copper anions such as. These organic acid salts of copper can be used alone or in combination of two or more. Further, it is preferable that these organic acid salts of copper be dissolved in the reaction mixture, but it is also possible for some of them to remain insoluble. The usage amount of these organic acid salts of copper is
0.004 to 1 liter of reaction mixture as copper atoms
It is 0.4 gram atom. However, when copper chloride is used as the chlorine compound as a co-catalyst, the copper atom of this compound is also included in the above range and an organic acid salt of copper is used. When the amount of copper is less than this range, almost no reaction occurs, and when it is more than this range, by-products increase. More preferably 0.008 to 0.3 gram atoms per liter of reaction mixture. The chlorine compound, which is the second component of the cocatalyst, is
Chlorine or its solution, hydrogen chloride or its solution,
amine hydrochloride, and chlorine-containing compounds that tend to generate chlorine ions, such as tert-butyl chloride, phosgene, phosphorus pentachloride, phosphorus oxytrichloride, or titanium, vanadium, manganese, iron, copper, zinc, or Examples include chloride or oxychloride depending on the valence of metal such as aluminum. These chlorine compounds may be used alone or in combination of two or more. These chlorine compounds are used in an amount that is less than 2, ie, more than 0 and less than 2, in terms of the ratio of chlorine atoms to copper atoms present in the reaction mixture. However, when using palladium chloride as the main catalyst,
Although it is usually a trace amount, it is within the range of the amount including the chlorine atoms from palladium chloride. When the ratio of chlorine atoms to copper atoms is 0, that is, when no chlorine atoms are present, almost no reaction occurs. When this ratio increases to 2 or more, by-products increase and the selectivity and yield of cinnamic acid esters decrease. Preferably it is 0.02-1.99 gram atomic ratio. The manganese or zinc compound which is the third component of the cocatalyst in the method of the present invention may be manganese or zinc salts of inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid or carbonic acid, acetate salts, propionate salts, or stearic acid salts. salts of aliphatic carboxylic acids, such as salts, or salts of aromatic carboxylic acids, such as benzoates;
Alternatively, salts of organic anions such as acetylacetonate may be used. It is preferable that these compounds are dissolved in the reaction mixture, but there is no problem even if some of them are insoluble. The amount of these manganese or zinc compounds used is such that the ratio of manganese or zinc metal atoms to copper atoms present in the reaction mixture is from 0.05 to 50, more preferably from 0.1 to 10. Two or more kinds of manganese or zinc compounds can also be used at the same time. The manganese or zinc chloride can also serve as part or all of the chlorine compound that is the second component of the cocatalyst. The method of the present invention may be carried out using either a batch method or a continuous flow method. The total pressure of the reaction in the method of the present invention depends on the partial pressures of carbon monoxide and oxygen or inert gas used, but is usually 200 atmospheres or less, preferably
The pressure is 1.0 to 100 atmospheres. Reaction temperature is room temperature to 200℃, preferably 40 to 160℃
It is. The reaction time varies depending on the reaction conditions, but is usually 0.01 to 24 hours, preferably 0.05 to 10 hours. After the reaction is completed, the cinnamic acid esters can be separated from the reaction product liquid by a conventional separation method such as distillation or extraction. (Actions and Effects of the Invention) According to the method of the present invention, a preferable range of the amount of copper atoms serving as a cocatalyst and a preferable range of the ratio of chlorine atoms to copper atoms can be given to the reaction system, and the reaction can be carried out within these ranges. This makes it possible to produce cinnamic acid esters with surprisingly high reaction performance using an extremely small amount of palladium-based catalyst and at low partial pressures of carbon monoxide and oxygen, making it extremely advantageous industrially. This is a method for producing cinnamic acid ester. (Example) Hereinafter, the method of the present invention will be explained in more detail with reference to Examples and Comparative Examples. Example 1 28.4 milligrams (0.160 mmol) of palladium chloride and cupric acetate monohydrate were placed in a glass cylindrical container.
7.61 g (38.1 mmol) and 12.3 g (50.2 mmol) of manganese acetate tetrahydrate were weighed out, a small amount of methanol was added to this, and 83.33 g (800 mmol) of styrene was weighed out. The hydrogen chloride gas whose concentration was measured just before was absorbed into methanol (concentration 1.5N) was added to 15.0
ml was added so that the amount of hydrogen chloride was 22.5 mmol, and methanol was further added to make the total volume 400 ml.
The amount of copper atoms per liter of reaction mixture is 0.095
It is a gram atom, and the gram atomic ratio of chlorine atoms to copper atoms is 0.60. 1 of this glass container
into an autoclave reactor. The reactor is equipped with a Teflon stirring blade, a glass-protected temperature measuring tube, a Teflon gas injection tube and a reflux condenser. Carbon monoxide:oxygen:nitrogen composition ratio is 8.8:5.4:
85.8 (by volume, analyzed by gas chromatography) is prepared in advance in a pressure-resistant container, and this mixed gas is introduced into the reactor to reduce the total pressure.
Maintained at 10 atm and output 4.2 liters/min (standard condition)
Continue stirring vigorously until the mixture reaches 100%.
The reaction was carried out at ℃ for 3 hours. The partial pressures of carbon monoxide and oxygen in the reactor are 0.88 and 0.54 atm, respectively. During the reaction, the outlet gas was discharged through a water-cooled reflux condenser, and the entrained low-boiling substances were refluxed to the reactor. After the reaction was completed, the reaction solution was cooled and depressurized, and the extracted reaction solution was analyzed by liquid chromatography, and found to be 54.4 mmol of styrene, 666.4 mmol of methyl cinnamate, and 16.3 mmol of by-produced dimethyl phenylsuccinate.
It contained mmol. Styrene conversion rate 93.2
%, the selectivity of methyl cinnamate (yield based on consumed styrene) was 89.4%, and the yield of methyl cinnamate (yield based on charged styrene) was 83.3%. The number of moles of ester (hereinafter abbreviated as Pd turnover rate) is
It was 4170. High catalytic activity and high reaction results were obtained even with low partial pressures of carbon monoxide and oxygen. Example 2 Palladium acetate 35.92 mg (0.160 mmol), cupric acetate monohydrate 5.99 g (30.0 mmol), cupric chloride 1.34 g (10.0 mmol)
After taking 12.3 g (50.2 mmol) of manganous acetate tetrahydrate and adding some methanol, 83.33 g (800 mmol) of styrene was added, and methanol was further added to bring the total volume to 400 ml. The total amount of copper atoms per liter of reaction mixture is 0.10 gram atoms, and the ratio of chlorine atoms to copper atoms is 0.50. The reaction was carried out in the same manner as in Example 1. The partial pressures of carbon monoxide and oxygen remain unchanged, respectively.
0.88 atm and 0.54 atm. The conversion rate of styrene was 93.3%, the selectivity of methyl cinnamate was 92.4%, the yield of methyl cinnamate was 86.2%, and Pd
The rotation rate was 4310. Examples 3 to 6 and Comparative Examples 1 to 4 All the same as Example 2 except that the amounts of cupric acetate monohydrate and cupric chloride used and reaction times were changed as shown in Table 1. I did the same. The partial pressures of carbon monoxide and oxygen vary slightly due to variations in the composition during the preparation of the mixed gas, but the extent is 0.80 to 0.90 atm for carbon monoxide and 0.50 to 0.57 for oxygen.
It is a range of atmospheric pressure. The results are shown in Table 1 together with the results of Example 2.

[Table] Example 7 Carbon monoxide:oxygen:nitrogen composition ratio is 8.5:5.3:
The same procedure as in Example 2 was carried out except that a mixed gas of 86.2% (by volume) was used and the total reaction pressure was 6 atm. The partial pressures of carbon monoxide and oxygen are each 0.51
atmospheric pressure and 0.32 atmosphere. Styrene conversion rate
88.6%, the selectivity and yield of methyl cinnamate are 90.7% and 80.4% respectively, and the Pd turnover is 4020
It was hot. Example 8 5% instead of palladium acetate in Example 2
The procedure was the same as in Example 2 except that 510 mg of Pd/c (5% by weight of palladium supported on activated carbon) was used and the reaction time was 3.5 hours.
Methyl cinnamate was obtained with a yield of 72.3%. Examples 9 to 13 and Comparative Example 5 The reaction was carried out in the same manner as in Example 2 except that 0.13 mmol of the palladium compound was used and the type and amount of each cocatalyst component was changed as shown in Table 2. Ta. The partial pressures of carbon monoxide and oxygen are respectively
Within the range of 0.8-0.9 atm and 0.50-0.57 atm. Copper atoms in the reaction mixture are 0.1 gram atom/
and the gram atomic ratio of chlorine atoms to copper atoms is 0.5. The results are shown in Table 2.

[Table] Shows

Claims (1)

[Claims] 1. When producing the corresponding cinnamic acid esters by reacting styrenes, carbon monoxide, alcohol and oxygen, palladium metal or its compound is used as the main catalyst, and (1) an organic acid salt of copper as a co-catalyst, (2) ) chlorine compound and (3) manganese or zinc compound to remove copper atoms in the reaction mixture.
The reaction is carried out at 0.004 to 0.4 gram atom/, and the gram atomic ratio of chlorine atoms to copper atoms is less than 2, and the partial pressure of carbon monoxide is 1 atm or less and the partial pressure of oxygen is 1 atm or less. A method for producing cinnamic acid esters.