JPS63196543A - Production of carboxylic acid ester - Google Patents

Abstract

PURPOSE:To obtain the titled compound under mild reaction condition in high yield, by reacting a carboxylic acid or its anhydride with H2 in the presence of an easily separable and recoverable heterogeneous solid catalyst available at a low cost. CONSTITUTION:The objective compound can be produced by the catalytic reaction of (A) a 1-15C aliphatic or aromatic carboxylic acid (e.g. acetic acid) or its Anhydride (e.g. acetic anhydride) with (B) H2 at a molar ratio (H2/total carboxylic acid) of 0.1-100 at 50-400 deg.C under normal pressure-150atm in vapor phase or liquid phase in the presence of (C) a solid catalyst containing Mo or W supported on a carrier such as silica, alumina, etc., and optionally added with a slight amount of other catalyst component containing a group VIII metal or silver, etc., as a cocatalyst component (e.g. Mo-SiO2, Ag-Mo/SiO2, W/SiO2, Ag-W-P/SiO2, etc.). The above catalyst can be produced by conventional method for the production of metallic catalyst, oxide catalyst, supported catalyst, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a method for producing a carboxylic acid ester by reacting a carboxylic acid or a carboxylic acid anhydride with hydrogen in the presence of a solid catalyst.

[Prior art 1] Conventionally, a method for producing ethyl acetate by hydrogenating acetic acid uses ruthenium (US Pat. No. 1,260,780).
7 specification, JP-A-58-192850) or one using rhenium [Journal of O Nick Chemistry (J, Org, Chell) vol. t24,
1847 pages (1959), Volume 27, 440
Pages 0 and 4402 (1962), Volume 28,
2345 pages and 2347 pages (1967) 1 are known. In addition, methods for producing ethyl acetate by hydrogenating acetic anhydride include a method using palladium (Japanese Unexamined Patent Application Publication No. 61-5050), a method using ruthenium (UK Patent No. 2129430, Japanese Unexamined Patent Publication No. 59-1988),
-157053, U.S. Pat. No. 4,485,245, U.S. Pat. No. 4,485,246) and a method using rhenium (West German Patent No. 3,407,092)
etc. are known. However, all of these methods use expensive components such as precious metals or rhenium as main catalysts, and some of them require extremely harsh reaction conditions (for example, over 150 atmospheres) or require separation of the catalyst in a homogeneous liquid phase system. It has drawbacks such as difficulty in collection.

[Problem to be Solved by the Invention 1] The present invention provides a method for producing a carboxylic acid ester by reacting a carboxylic acid, etc. with hydrogen, in the presence of an inexpensive solid catalyst, under mild reaction conditions, and in which the solid used is The present inventors provide a method for producing a carboxylic acid ester using a heterogeneous reaction system in which the catalyst is easily separated. As a result of various studies on methods for producing carboxylic acid esters by reacting hydrogen with hydrogen, we found that it is possible to use molybdenum or tungsten, which are available at low cost, as a solid catalyst, and that this catalyst can be easily separated and recovered. The present invention was completed after observing the above.

That is, the present invention provides a method for producing a carboxylic acid ester by bringing a carboxylic acid or carboxylic acid anhydride and hydrogen into contact with a solid catalyst containing molybdenum or tungsten.

The carboxylic acid or carboxylic acid anhydride used as the raw material of the present invention is an aliphatic or aromatic carboxylic acid having 1 to 15 carbon atoms or an acid anhydride thereof, that is, a hydrocarbon residue directly bonded to the carboxylic acid group. Chain or branched alkyl groups, alkenyl groups, aralkyl groups, or alkyl-substituted or unsubstituted 7-aryl groups can be used,
For example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, turic acid, glyfuric acid, cyclohexanecarboxylic acid,
Aliphatic-basic carboxylic acids such as phenylacetic acid, aliphatic dibasic carboxylic acids such as succinic acid, glutaric acid, and adipic acid, aromatic-basic carboxylic acids such as benzoic acid and toluic acid, heptaric acid, and naphthalene. Aromatic dibasic carboxylic acids such as -1,2-dicarboxylic acid and their acid anhydrides can be used.

Among these, saturated or unsaturated aliphatic carboxylic acids having 1 to 9 carbon atoms and their acid anhydrides are preferably used, and in the case of acid anhydrides, those in which two acyl groups are the same are preferred.

The carboxylic acid and carboxylic acid anhydride as raw materials of the present invention may be supplied to the reaction alone, or a mixture of the two may be used.

Molybdenum or tungsten contained in the catalyst used in the present invention may be present in the form of an elemental metal, an alloy, an intermetallic compound, or various inorganic compounds such as oxides, carbonates, halides, hydroxides, and sulfates. Can be done. Although the form in the catalytic state is not clear, preferred forms are metals or alloys, oxides, or partially reduced oxides or composite oxides with a high specific surface area.

Moreover, molybdenum and tungsten can be coexisting in the solid catalyst in any ratio.

The solid catalyst containing molybdenum or tungsten used in the present invention is usually a carrier such as alumina, silica, silica-alumina, zeolite, titania, zirconia, activated carbon, diatomaceous earth, heteropolyacid or its salt, etc., and a molybdenum or tungsten element. An alloy or a compound supported thereon is used. The supported amount is preferably about 0.01 to 80% by weight based on the total amount of the solid catalyst.

A small amount of other catalyst components such as Group 8 metals or silver can be added to the solid catalyst of the present invention as a co-catalyst.

In this case, the amount added is preferably 0.001 to 30% by weight based on molybdenum or tungsten.

Addition of a small amount of this co-catalyst has the effect of lowering the temperature of the reduction reaction of the present invention and shortening the time of the reduction reaction.

The reaction of the present invention can be carried out at a reaction temperature of 50 to 400°C, a reaction pressure of normal pressure to 150 atm, using a fixed bed or fluidized bed catalyst bed, in a liquid phase or a gas phase.

The reaction method of the present invention can be a batch method, a semi-continuous method, or a continuous method, and the amount of catalyst used is 0.0001 to 50% by weight of the solid catalyst based on the reactants in the batch method, and in the flow method The space velocity (W) of the catalyst layer (ISV) is 0.1 to 100
The reaction can be carried out using a solid catalyst so that hr'.

In the present invention, the reaction can be carried out using hydrogen, expressed as a molar ratio of H2/carboxylic acid, etc., of 0.1 to 100 relative to the total amount of carboxylic acid and carboxylic anhydride charged.

In the present invention, a diluent, for example, an inert solvent such as a hydrocarbon or an inert gas such as nitrogen, helium, or argon, may be used as appropriate.

The method for preparing the catalyst of the present invention is not particularly limited; metal catalysts,
All known methods for preparing oxide catalysts, supported catalysts, etc. can be used.

Among these, when using the supported impregnation method, any material can be used as long as it contains molybdenum or tungsten and is soluble in a solvent such as water or an organic solvent. For example, ammonium molybdate, tungsten Preferred examples include ammonium acid, 12-tungstophosphoric acid, 12-molybdophosphoric acid, tungsten carbonyl compounds, and molybdenum carbonyl compounds.

Further, when the co-catalyst is included in the solid catalyst by, for example, an impregnation method, any co-catalyst can be used as long as it is a component such as a Group 8 metal or silver and is soluble in a suitable solvent.

The catalyst of the present invention is supported by making the above-mentioned raw materials into a solution, impregnating it onto a predetermined carrier, and drying it. Catalysts obtained by various preparation methods can be used as they are, but it is usually preferable to perform an activation treatment before use. In particular, reduction treatment with hydrogen is performed at a temperature of 50 to 500°C and a hydrogen partial pressure of 1 to 200 atm. It is desirable to process it.

By hydrogen treatment before using the solid catalyst, most of the molybdenum compounds or tungsten compounds are reduced to simple substances,
As a result, the reaction rate of the present invention can be increased and the life of the catalyst can be extended.

The form of the solid catalyst of the present invention is not particularly limited, and various shapes and sizes can be used, such as columnar extruded products, tablets, pellets, particles, and powders. Furthermore, in order to impart mechanical strength to these catalysts, various binders can be added to the catalysts to form them.

Note that the hydrogen used in the reaction and the unreacted carboxylic acid or carboxylic acid anhydride can be purified to a necessary degree and then recycled to the reaction system again.

[Effects of the Invention] The method for producing a carboxylic acid ester of the present invention is advantageous in that the ester can be produced in good yield using an inexpensive solid catalyst, and that the catalyst can be easily separated because a heterogeneous solid catalyst is used. It is.

[Example 1 The present invention will be explained in more detail with reference to Examples.

Example 1 Ammonium molybdate (Ntl-)JotO□,・
4 ■ 2011.65y with about 60℃l of distilled water 12f)I
It was dissolved in Il.

To this, 38.0 g of silica gel (10 del, manufactured by Davison Co., Ltd.) previously dried at 200°C was added, evaporated to dryness on a hot water bath, and further dried overnight in an oven at a temperature of 150°C.
A solid catalyst with a molybdenum component supported on silica sol was obtained.

5 g of this solid catalyst was packed into a reaction tube of a pressurized flow reactor, and heated at normal pressure at a temperature of 450°C for 5.5 hours, and then at the same temperature and 60 atm for 3 hours at a flow rate of IO1/
A reduction treatment with a hydrogen flow of hr was carried out.

Next, acetic anhydride (11.0 g/hr) and hydrogen (5.31/hr) were supplied as raw materials to the reactor, and the reaction was carried out at a reaction temperature of 280° C. and a pressure of 60 atm. The reaction r& results are shown in Table 1.

Example 2 0.0.107 g of silver nitrate AgN was dissolved in 3 (hN) distilled water. In this, the solid catalyst 11 prepared in Example 1 was dissolved.
．． 0 g was added, evaporated to dryness on a hot water bath, and further dried overnight in an oven at 150''C to obtain a solid catalyst (^rHo/SiO□) in which silver and molybdenum components were supported on silica sol. Pretreatment and reaction were carried out in the same manner as in Example 1. The reaction results are shown in Table 1.

Example 3 12Molybdophosphoric acid (H3PMO12040'XH20
) 11.92g and 8gNOs 0.479 to 100
It was dissolved in z1 distilled water. 200 in advance into this
Silica gel (Devison It gel) dried at ℃3
S.OI? was added, evaporated to dryness on a water bath, and then dried in an oven at 60°C overnight. Furthermore, under normal pressure, the temperature is 450℃
for 6 hours with hydrogen flow 5011/win and nitrogen flow 1
00ti'/sin, to H-No-P/
A SiO□ solid catalyst was obtained. The solid catalyst was heated at 60 atm and 400°C for 6 hours at 10 i'/h prior to the reaction.
The reduction treatment was carried out by a hydrogen flow with a flow rate of r.

A reaction tube was filled with 5 g of this solid catalyst, and acetic anhydride was hydrogenated in a pressurized flow reactor. The reaction was carried out at a reaction temperature of 280°C and a pressure of 60 atm, with raw materials supplied at acetic anhydride charging rate of 11.0 y/hr and hydrogen charging rate of 5.31/hr.The reaction results are shown in Table 1. show.

Example 4 Ammonium tungstate (Ni1.). -1□0
□、・5H205,631? 10 heated to about 70℃
It was dissolved in 0*1 distilled water. 20 in advance into this
Silica sol (ID Del, manufactured by Davison) 2 dried at 0°C
0. Oy was added, evaporated to dryness on a hot water bath, and further dried overnight in an oven at 150°C to obtain a solid catalyst in which 12-tungstophosphoric acid and a silver component were supported on silica gel. Thereafter, pretreatment and reaction were performed in the same manner as in Example 1.

The reaction results are shown in Table 1.

Example 5 12-tungstophosphoric acid H3pH 112040・XH2O
11, Oy and ^gNOz O, 47g to 100i+1
was heated and dissolved in distilled water.

38. Silica gel (Davison ID gel) dried at 200°C in advance. After evaporating to dryness on a hot water bath, the mixture was dried in an oven at 60° C. overnight to obtain a solid catalyst in which 12 tungstophosphoric acid and silver nitrate were supported on silica sol. Thereafter, a reaction was carried out in the same manner as in Example 1.

The reaction results are shown in Table 1.

Example 6 Ammonium molybdate (NH=)iMotO□4・
4112011.65g was dissolved in 120x1 distilled water, 13g of PdC1zO was dissolved in concentrated hydrochloric acid 1.0. , and 20m
1 was dissolved in the mixed aqueous solution. Into the mixture of both, 38.0 g of silica gel (ID gel manufactured by Davison Co., Ltd.) previously dried at 200° C. was added, and after evaporating to dryness on a hot water bath, it was dried in an oven at 150° C. overnight. Furthermore, hydrogen reduction (L
A solid catalyst (Pd-No/SiO□) in which a molybdenum component and a palladium component were supported on silica gel was obtained.

A reaction tube was filled with 10 g of this catalyst, and acetic anhydride was hydrogenated in a pressurized flow reactor. In addition, prior to the reaction, the catalyst was heated at normal pressure, 350°C for 2 hours, and then at the same temperature, 60 atm, for 4 hours.
Reduction treatment was carried out with a hydrogen flow of 5.31/hr.

The reaction was carried out under conditions of a reaction temperature of 280° C. and a pressure of 60 atmospheres, with raw materials being supplied at a rate of acetic anhydride of 11.0 y/hr and hydrogen of 5.31/hr. The reaction results are shown in Table 1.

Example 7 Acetic acid charging rate 11,0y/hr and hydrogen charging rate 5
, 31/hr except that the raw materials were supplied in the same manner as in Example 1. The reaction results are shown in Table 2.

Example 8 Acetic acid charging rate 11. Oy/hr and hydrogen charging rate 5
．． Table 2 shows the results of one reaction conducted in the same manner as in Example 2 except that the raw materials were supplied at a rate of 31/hr.

Example 9 Acetic acid charging rate 11. Table 2 shows the results of a reaction conducted in the same manner as in Example 3, except that the raw materials were supplied at Oy/h'r and hydrogen charging rate of 5.3 f/hr, and the reaction temperature was 252°C.

Example 10 Table 2 shows the results of one reaction conducted in the same manner as in Example 9 except that the reaction temperature was 281°C.

Example 11 Acetic acid charging rate 11. Gy/hr and hydrogen charging rate 5
．． The same procedure as in Example 4 was carried out except that the raw materials were supplied at a rate of 31/hr and the reaction temperature was 280°C. The reaction results are shown in Table 2.

Example 12 Acetic acid charging rate 11.0y/hr and hydrogen charging rate 5
Table 2 shows the results of the 0 reaction, which was carried out in the same manner as in Example 5, except that the raw materials were supplied at a rate of , 31/hr and the reaction temperature was 280°C.

Example 13 Ammonium molybdate (NH4)sMotO□<
・Dissolve 4H201,104# in 50111 distilled water, 20,033g of PdCl and 2.43g of concentrated hydrochloric acid. and distilled water 2011 were dissolved in an aqueous solution. Activated carbon (dried at 200℃) is added to the mixture of both.
Mitsubishi Chemical Industries Diamond Hope 008) 20. After evaporating to dryness on a hot water bath, the mixture was dried in an oven at 60° C. overnight. Furthermore, at normal pressure and temperature of 500°C under hydrogen flow, 7
A solid catalyst (Pd-No/C) having a molybdenum component and a palladium component supported on carbon was obtained by reduction with a hydrogen flow of 150 xil in.

This catalyst 101? was filled into a reaction tube, and hydrogenation reaction of acetic acid was carried out in a pressurized flow reactor. The reaction was carried out at an acetic acid charging rate of 11. Oy/hr and hydrogen charging rate 5.31/hr
The reaction temperature was 300° C. and the pressure was 60 atm. The reaction results are shown in Table 3.

Example 14 The reaction raw materials were acetic acid (11, Oy/hr) and hydrogen (5,3 Oy/hr).
j! /hr) and the reaction temperature was 250°C, but the same procedure as in Example 6 was carried out. The reaction results are shown in Table 3.

Example 15 The same procedure as in Example 14 was carried out except that the reaction temperature was 280°C. The reaction results are shown in Table 3.

Example 16 The same procedure as in Example 7 was carried out except that the raw materials were supplied at a propionic acid charging rate of 11.0 g/hr and a hydrogen charging rate of 5.31/hr. The main product was propyl propionate. The reaction results are shown in Table 4.

Example 17 The same procedure as in Example 7 was carried out except that the raw materials were supplied at an n-butyric acid charging rate of 11.0 g/hr and a hydrogen charging rate of 5.3 N/hr. The main product was n-butyl n-butyrate. The reaction results are shown in Table 4.

Claims (1)

[Claims] 1. A method for producing a carboxylic acid ester, which comprises bringing a carboxylic acid or carboxylic acid anhydride and hydrogen into contact with a solid catalyst containing molybdenum or tungsten.