JPS625420B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to ortho-chlorotoluene (hereinafter referred to as OCT).
It is abbreviated as. ) is ammoxidized with a gas containing ammonia and oxygen, using a catalyst having the composition V _a P _b Li _c O _d .
Chlorobenzonitrile (hereinafter abbreviated as OCBN)
Relating to a manufacturing method. (In the formula, a, b, c, and d represent the number of atoms of vanadium, phosphorus, lithium, and oxygen.
In this case, b takes a value of 0.1 to 3, c takes a value of 0.01 to 1.5, and d takes a value naturally determined from other valences. ) In recent years, demand for OCBN dyes has increased, and its industrial production has become an important issue. Hitherto, there has been known a method for obtaining a corresponding aromatic nitrile by catalytically reacting a mixed gas containing an alkyl-substituted aromatic compound, ammonia and oxygen in the presence of a suitable catalyst, such as a vanadium oxide catalyst using alumina as a carrier. There is. However, in the case of OCT, since the reactive group has an active chlorine atom at the ortho position, catalysts such as those used for conventional ammoxidation result in low yields of OCBN due to excessive oxidation. For this purpose, research has been conducted to improve catalysts, and a vanadium-phosphorus-oxygen catalyst (hereinafter abbreviated as V-P catalyst) has been proposed, but it still has problems in terms of OCBN yield, catalyst life, etc. It's not satisfying. The present inventors completed the present invention as a result of intensive studies aimed at achieving a better OCBN yield and improving catalyst life. That is, as a result of examining the V-P catalyst from various aspects, the present inventors found that the addition of lithium met the above objective. The effect of lithium is thought to be in adjusting the acid and base sites on the catalyst and preventing phosphorus from scattering. A particularly preferred catalyst in the present invention has the following composition. a:b:c=1:0.3~2.5:0.01~1 (However, the description of oxygen is omitted because it is a value naturally determined from the valence of other elements.) The catalyst used in the present invention is OCT Although it was developed for the ammoxidation of other halogenated aromatic methyl compounds, it can also be used for the ammoxidation of other halogenated aromatic methyl compounds. For example, it can also be used in the ammoxidation of fluorotoluenes or para- and metachlorotoluene, in which case the yield is
Better than OCT. Generally known methods used for preparing this type of catalyst can be applied to the preparation of the catalyst in the present invention. For example, it can be obtained by adding a vanadium compound and a phosphorus compound to water, further adding a lithium compound, further adding a carrier if necessary, evaporating to dryness, and firing the resultant. Firing temperature is 450
℃~800℃ is preferred. The compounds of each constituent element used when preparing the catalyst are not limited to special ones;
Any commonly used compounds can be used. For example, vanadium compounds include ammonium metavanadate, vanadium pentoxide,
Vanadyl oxalate, vanadyl phosphate, etc. are used as phosphorus compounds, phosphoric acid, phosphate, hypophosphorous acid, phosphorus pentoxide, etc., and lithium compounds include lithium hydroxide, lithium carbonate, lithium nitrate, lithium sulfate, chloride, etc. Lithium, lithium bromide, lithium iodide, lithium fluoride, lithium phosphate, etc. can be used. As the carrier, materials used in conventional catalysts for gas phase catalytic oxidation reactions, such as alumina, silica, beryllia, magnesia, titania, silicon carbide, asbestos, diatomaceous earth, and zeolite, can be used. The concentration of OCT in the reaction feed gas is 0.5
~10 mol% is preferred. OCT in reaction feed gas
And the preferred molar ratio of ammonia and oxygen is OCT:
Ammonia:oxygen=1:2-5:1.5-10. The reaction feed gas is water vapor and other inert gases,
For example, it may contain nitrogen, carbon dioxide, and carbon monoxide. The reaction temperature is preferably 350°C to 650°C.
A particularly preferred reaction temperature is 400°C to 600°C. The contact time is preferably 0.5 seconds to 10 seconds. The reaction can be carried out under increased pressure, normal pressure or reduced pressure. The reaction product gas is collected in a water-cooled trap,
Complete product collection was achieved by passing the off-gas through chilled acetone. The present invention will be specifically described below with reference to Examples. OCT reaction rate, OCBN yield, and OCBN selectivity were calculated according to the following definitions. OCT reaction rate (%) = Number of moles of OCT reacted / Number of moles of OCT supplied × 100 OCBN yield (%) = Number of moles of OCBN produced / Number of moles of OCT supplied × 100 OCBN selectivity (%) =Number of moles of OCBN produced/Number of moles of OCT reacted×100 In addition, in the examples, the description of oxygen in the catalyst composition was omitted because it was a value naturally determined from the valence of other elements. Example 1 117 g of ammonium metavanadate is suspended in 1 liter of water and heated to completely dissolve it. Add 139 g of 85% phosphoric acid to this solution, and then add 13.8 g of lithium nitrate. While thoroughly stirring the resulting solution, 76.8 g of silica aerosol is added to form a slurry. After spray drying this, it is molded,
It was fired at 580°C for 3 hours in an oxidizing atmosphere. The composition of the catalyst thus obtained was V ₁ P ₁ . ₂ Li ₀ . ₂ (SiO ₂
30%). Twenty milliliters of this catalyst was charged into a fixed bed reactor, and the reactor was immersed in an alumina fluidized bath to maintain the reaction temperature at 450°C. OCT3.2 mol%, oxygen 9.6 mol%, ammonia
11.5 mol%, water vapor 37.3 mol%, nitrogen 38.4 mol%
A mixed gas containing
The reaction took place in seconds. OCT 5 hours after the start of the reaction
The reaction rate was 97.9%, the yield of OCBN was 90.1%, and the selectivity was 92.0%. Comparative Example 1 The same procedure as in Example 1 was carried out except that lithium nitrate was not added during catalyst preparation. OCT
The reaction rate was 97.7%, the yield of OCBN was 85.0%, and the selectivity was 87.0%. Examples 2 to 4 The same procedure as in Example 1 was carried out except that the catalyst was prepared by changing the atomic ratio of V:Li.
The results are shown in Table-1.

[Table] Example 5 A continuous reaction was carried out using the catalyst of Example 1.
The OCT reaction rate at 3000 hours after the start of the reaction is
96.4%, OCBN yield is 89.6%, OCBN selectivity is
It was 92.9%, which was almost unchanged compared to the value 5 hours after the start of the reaction.

Claims (1)

[Claims] 1. When ortho-chlorotoluene is ammoxidized with a gas containing ammonia and oxygen, V _a P _b
A method for producing ortho-chlorobenzonitrile, characterized by using a catalyst having a composition of Li _c O _d . (In the formula, a, b, c and d represent the number of atoms of vanadium, phosphorus, lithium and oxygen.
In this case, b takes a value of 0.1 to 3, c takes a value of 0.01 to 1.5, and d takes a value naturally determined from other valences. )