JPH0149342B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing malonic acid diester. Malonic acid diester is used as a raw material for medicines, agricultural chemicals, dyes, etc., and it is desired to establish an inexpensive method for producing it. The present invention relates to an improved method for producing malonic acid diester by reacting a halogenated acetate with carbon monoxide and alcohol. (Prior art) A method for producing malonic acid diester by reacting a halogenated acetate with carbon monoxide and alcohol has been proposed, and the
Publication No. 16134 proposes a method in which alcohol, a base, a rhodium catalyst, and optionally an iodine compound are present in a liquid phase. The present inventors previously reported in Japanese Patent Application No. 59-218511 (Japanese Unexamined Patent Publication No. 61-97245) that a halogenated acetate, carbon monoxide, and alcohol were subjected to a gas phase catalytic reaction in the presence of a rhodium compound. An improved method was proposed. (Problems to be Solved by the Invention) The conventional methods of producing malonic acid diester by reacting these halogenated acetic esters with carbon monoxide and alcohol have the following problems. (1) All of these methods produce a small amount of malonic acid diester per unit amount of catalyst. (2) The method of reacting liquid halogenated acetate ester involves uniform mixing with a large amount of basic compound in order to capture the halogen produced in the reaction, and the halogenated metal salt after the reaction is mixed with malon. Complex operations such as filtration and extraction are required to separate it from the acid diester and catalyst. The present invention is the result of extensive research in order to solve these problems and provide a method for producing malonic acid diester that is simpler and more efficient. (Means for Solving the Problems) The present invention is characterized in that in reacting a halogenated acetate with carbon monoxide and alcohol in the presence of a rhodium compound, a gas phase catalytic reaction is carried out in the presence of an iodine compound. This is a method for producing malonic acid diester. The present invention will be explained in more detail below. The halogenated acetate used in the present invention is not particularly limited as long as it has a boiling point of 250°C or less, but lower alkyl esters such as methyl, ethyl, n-propyl, isopropyl, butyl are preferable, and the halogen substituent is particularly Chlorine and bromine are preferred. The alcohol used in the present invention is not particularly limited as long as it is an aliphatic alcohol having 1 to 8 carbon atoms, but it is preferably the same alcohol as the ester residue of the halogenated acetate ester used. For example, methanol is used for halogenated methyl acetate, and isopropyl alcohol is used for halogenated isopropyl acetate. The carbon monoxide used does not need to be of particularly high purity, and carbon monoxide in which an inert gas coexists may be used. The rhodium compound used as a catalyst in the present invention is a rhodium halide, an inorganic acid salt, or a complex compound, and examples thereof include RhCl _{3.3H 2} O,
RhBr ₃・2H ₂ O, Rh (NO ₃ ), Rh ₂ (CO) ₄ Cl ₂ , Rh
(CO)Cl[P( _C6H5 ) ₃ ] ₂ , RhCl _[ P( _{C6H5 ) 3} ] ₃ ,
_Rh2O3・_5H2O , ( _NH4 ) _3RhCl6 ^, _RhI3・_{xH2O ,} etc. These compounds do not need to be highly pure;
For example, it may contain salts such as sodium chloride and potassium chloride. In the present invention, a metal iodide is used as the iodine compound added to the catalyst. For example,
LiI, KI, NaI, BaI ₂ , CsI, RbI, CoI ₂ , CaI ₂ and the like, preferably NaI, KI, BaI ₂ .
Further, these iodine compounds may be hydrated. Rhodium compounds are usually supported on inert carriers such as activated carbon, alumina, silica, diatomaceous earth, pumice, zeolite, and molecular sieve.
Activated carbon is particularly preferred. In this case, the amount of supported rhodium compound is expressed as rhodium metal equivalent to the support.
It is sufficient to use it in a range of 0.5 to 20% by weight. The rhodium compound is supported on the carrier by a known catalyst preparation method. The iodine compound is used by being supported on a carrier in the same manner as the rhodium compound. In this case, the rhodium compound may be supported simultaneously with the rhodium compound or separately, but it is advantageous to support the rhodium compound separately. In this case, the amount of the iodine compound added is 1:0.01 to 1:1 in molar ratio to the rhodium compound.
50, preferably 1:01 to 1:10. In carrying out the present invention, carbon monoxide and gaseous halogenated acetate and alcohol are directly or diluted with an inert gas and introduced in a gas phase onto a rhodium compound catalyst to which an iodine compound has been added. and react. The reactor used is a conventional fixed bed reactor used for gas phase reactions. The reaction temperature is preferably 100°C to 300°C, and the reaction proceeds under normal pressure, but it can also be carried out under slightly increased pressure. The amounts of alcohol and carbon monoxide used in the present invention are preferably in the range of 2 to 100 mol and 1 to 100 mol, respectively, per 1 mol of halogenated acetic acid. In addition, the contact time of the raw material gas with the catalyst layer is 0.2
A range of ~10 seconds is preferred. In the present invention, the reactant discharged from the reaction tube is cooled and condensed according to a conventional method, and further subjected to a distillation operation to obtain malonic acid diester. (Example) Next, the present invention will be explained in more detail with reference to Examples. Example 1 After adsorbing 1 g of RhCl ₃ 3H ₂ O on 10 g of spherical activated carbon, a catalyst with an inner diameter of 25 cm was adsorbed with 0.63 g of KI.
After filling a heat-resistant glass reaction tube with a diameter of 600 mm and a height of 600 mm, the mixture was heated to 250° C. and carbon monoxide was introduced at a rate of 0.13 mol/hour for 1 hour. Next, carbon monoxide,
Methyl monochloroacetate and methanol at 0.20 per hour
A mixed gas was introduced into the reaction tube through a preheater maintained at 200° C. at a rate of 0.04 mol, 0.41 mol. The reaction was carried out at a reaction temperature of 250°C and under normal pressure. As a result of analyzing the reaction product by gas chromatography, dimethyl malonate was produced at the production rate shown in Table 1. Furthermore, the total amount of dimethyl malonate produced up to 72 hours after the start of the reaction was 670 mol/Kg of catalyst.

[Table] Example 2 The same procedure as in Example 1 was carried out except that 0.63 g of KI was replaced with 0.57 g of NaI.2H ₂ O. As a result of gas chromatography analysis of the reaction product, dimethyl malonate was produced at the production rate shown in Table 2. The total amount of dimethyl malonate produced up to 72 hours after the start of the reaction was 707 mol/Kg of catalyst.

[Table] Example 3 The same procedure as in Example 1 was carried out except that 0.63 g of KI was replaced with 1.62 g of BaI _{2.2H 2} O. As a result of gas chromatography analysis of the reaction product, dimethyl malonate was produced at the production rate shown in Table 3. The total amount of dimethyl malonate produced up to 72 hours after the start of the reaction was 629 mol/Kg of catalyst.

[Table] Example 4 The same procedure as in Example 1 was carried out except that methyl monochloroacetate and methanol were replaced with ethyl monochloroacetate and ethanol, respectively. As a result of analyzing the reaction product by gas chromatography, diethyl malonate was produced at the production rate shown in Table 4. In addition, the total amount of diethyl malonate produced up to 72 hours after the start of the reaction is
617 mol/Kg of catalyst.

[Table] Example 5 After 1 g of Rh(NO ₃ ) ₃ was adsorbed on 10 g of spherical activated carbon, a catalyst with an inner diameter of 25
After filling a heat-resistant glass reaction tube with a diameter of 600 mm and a height of 600 mm, the mixture was heated to 180° C. and carbon monoxide was introduced at a rate of 0.13 mol/hour for 1 hour. Next, carbon monoxide, methyl monochloroacetate, and methanol were introduced into the reaction tube as a mixed gas through a preheater maintained at 200° C. at a rate of 0.25 mol, 0.04 mol, and 0.20 mol per hour. The reaction was carried out at a reaction temperature of 180°C and under normal pressure. As a result of analyzing the reaction product by gas chromatography, dimethyl malonate was produced at the production rate shown in Table 5. Furthermore, the total amount of dimethyl malonate produced up to 72 hours after the start of the reaction was 330 mol/Kg of catalyst.

[Table] Comparative Example 1 When a test was conducted using the method of Example 1 without adding KI, the total amount of dimethyl malonate produced up to 72 hours after the start of the reaction was 441 mol/Kg.
It was a catalyst. Comparative Example 2 When a test was conducted using the method of Example 5 without adding KI, the total amount of dimethyl malonate produced up to 72 hours after the start of the reaction was 216 mol/Kg.
It was a catalyst. (Effects of the Invention) According to the present invention, since a basic compound is not required in the gas phase reaction, it is easy to mix the raw materials and obtain the product, and the catalyst efficiency is high and the operation is simple. malonic acid diester can be easily produced.

Claims (1)

[Claims] 1. A method for producing a malonic acid diester, which comprises carrying out a gas phase contact reaction in the presence of an iodine compound in the reaction of a halogenated acetate, carbon monoxide, and alcohol in the presence of a rhodium compound.