JPS6393759A - Production of aromatic hydrazo compound - Google Patents

Abstract

PURPOSE:To obtain the titled substance safely and inexpensively without causing problems of by-products, by reducing an aromatic azoxy compound with hydrazine hydrate in an aqueous solution of an alkali metal hydroxide in the presence of both a surface active agent and a Raney nickel without using an alcohol. CONSTITUTION:An aromatic azoxy compound shown by the formula (X is -H, -Cl, -OCH3 or -CH3) as a raw material and an alkali metallic hydroxide or alkaline earth metallic hydroxide are suspended in water and a small amount of a surface active agent, then Raney nickel catalyst is added to the suspension, hydrazine hydrate is gradually dripped at a fixed temperature, preferably 20-100 deg.C, especially 50-80 deg.C and the azoxy compound is reduced to give the aimed compound. An anionic surface active agent is preferably cited as the surface active agent and to be concrete, an alkylsulfuric ester, etc., may be cited. 60-40% hydrazine hydrate is effective and the amount used is 1.1-1.3mol based on 1mol azoxy compound.

Description

[Detailed description of the invention] Ritsuka Ritsuka The present invention relates to a method for producing aromatic hydrazo compounds.

[4] Conventionally, many methods for producing hydrazo compounds from azoxy compounds have been proposed, as shown below.

(i) Reduction method with zinc dust in ethanol in the presence of alkali metal hydroxide (N, Khalifa Soc
, y3740, 1958; B, T. Newbolt:
Canad, J., Chew.

42, 841.1964), but this is not a good method because of the flammability of ethanol, the ignitability of zinc dust, and the pollution nature of zinc oxide, a reaction by-product.

(ii) The use of aluminum instead of zinc has also been proposed, but aluminum powder is dangerous as it is flammable. (Unexamined Japanese Patent Publication No. 53-111021) (iii) Neutral reduction (Bechamp reduction) of azoxy compounds using cheap iron powder has been proposed, but it is difficult to separate the product hydrazo compound from the reaction by-product iron oxide. It is necessary to use an organic solvent such as benzene, which is dangerous and expensive considering the loss of solvent recovery. (Unexamined Japanese Patent Publication No. 52-3026)
(iv) A method has been proposed in which an azoxy compound is reduced with formaldehyde or paraformaldehyde in the presence of an alkali metal hydroxide using naphthoquinones as a catalyst (U.S. Pat. No. 2,794,046). Since it is used as a solvent, it is highly dangerous, and sodium formate, which is an oxidation product of formaldehyde, is generated and causes wastewater pollution. (B indicates the state of wastewater pollution.

0.0. (biological oxygen demand) and C, O, D, (chemical oxygen demand) values are very high.) (V) In the method (iv) above, no alcohol is used and the Although an improvement proposal using an activator has been proposed, it uses an expensive neutral polar solvent (iv
) method has the same drawbacks.

(vi) A method has been proposed in which an azoxy compound is reduced with glucose using naphthoquinone as a catalyst in the presence of an alkali metal hydroxide, but this method has the same drawback as method (iv) because the reduction is in alcohol (U.S. Patent No. 2, 7
No. 94,047).

(vii) A method has been proposed in which azoxy compounds are reduced with a mixed solution of sodium hydrogen sulfide/sodium thiosulfate using alcohol as a solvent, but this method is difficult to reduce due to the use of alcohol and the difficulty in processing the by-product, sodium thiosulfate. There's a problem.

(JP-A-51-97633 and JP-A-5L-10003
2) (ν1ii) A method has been proposed in which an azoxy compound is reduced with hydrogen or hydrazine hydrate using alcohol as a solvent and Raney nickel as a catalyst in the presence of an alkali metal hydroxide, but the use of alcohol is flammable. Because it is a solvent, it is very dangerous.
108932) As described above, none of the conventional methods is satisfactory in terms of economic efficiency, air pollution, pollution such as wastewater treatment, and danger such as ignition.

OBJECTIVES The present invention aims to provide a new and improved method for producing aromatic hydrazo compounds that overcomes the conventional drawbacks.

1-m set.

As a result of extensive research in order to achieve the above object, the present inventor has developed an aromatic azoxy compound having the following general formula (X represents -H, -+1, -OCH, or -CH) from an alkali metal. It consists of suspending the hydroxide or alkaline earth metal hydroxide in water and a small amount of surfactant, adding a Raney nickel catalyst and gradually adding dropwise hydrazine to reduce it to the aromatic hydrazo compound at normal pressure. It has been found that the above object can be achieved by providing a method for producing an aromatic hydrazo compound.

Aromatic hydrazo compounds are very useful compounds. This compound is obtained by reducing an aromatic nitro compound as shown in the reaction formula below, but via an azoxy compound as a reaction intermediate.

Nitro compound Azoxy compound Hydrazo compound 1st stage 2nd stage (In the above formula, X is -H, -CΩ, -OCH□ or -c
An excellent method has been discovered for the first step reaction leading to the azoxy compound (representing H3) (U.S. Pat. No. 2,799).
4°046), it can be produced safely and economically.

Therefore, many methods have been proposed to produce hydrazo compounds from nitro compounds all at once, but expensive reducing agents and expensive catalysts for the second stage reduction are also used for the first stage reduction. It is economically very undesirable to do so.

The present inventor researched a method for producing a hydrazo compound more safely and inexpensively than an azoxy compound produced safely and inexpensively, and in a manner that caused as little environmental pollution as possible, and discovered a new production method. In addition, the known methods of converting azoxy compounds into hydrazo compounds have problems with safety, environmental pollution of by-products, manufacturing costs, equipment, etc., and are judged to be inappropriate methods. As a result of research aimed at finding an inexpensive method that does not require special equipment (high pressure, high temperature, special stirring, etc.), they discovered a new manufacturing method that satisfies these points. Furthermore, the azoxy compound is converted to hydrazine hydrate in an aqueous solution of an alkali metal hydroxide or alkaline earth metal hydroxide using a Raney nickel catalyst in the presence of an anionic activator without using alcohols. We discovered that high yield and high purity hydrazo compounds can be obtained by reduction with .

The key to this discovery is that no dangerous flammable organic solvents are used;
The method is characterized in that it uses a Raney nickel catalyst that is available at low cost, uses hydrazine hydrate as a reducing agent, and uses an anionic surfactant to react in an aqueous solvent. In this case, the only reaction by-products produced are harmless water and nitrogen.

That is, in the present invention, an azoxy compound is suspended in an alkali metal hydroxide or an alkaline earth metal hydroxide, water, and a small amount of a surfactant, a Raney nickel catalyst is added, and while maintaining a constant temperature, hydrazine hydrates. The azoxy compound is reduced to a hydrazo compound by gradually adding the compound dropwise.

Examples of the alkali metal hydroxides include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the alkaline earth metal hydroxides include beryllium hydroxide, magnesium hydroxide, and calcium hydroxide. etc.

The surfactant is preferably an anionic surfactant,
Specifically, fatty acid salts, alkyl sulfate ester salts, and alkylbenzene sulfonates.

Alkylnaphthalene sulfonate, alkyl sulfosuccinate, alkyldiphenyl ether disulfonate,
Examples include alkyl phosphates, polyoxyethylene alkyl or alkylaryl sulfates, naphthalene sulfonic acid formalin condensates, special polycarboxylic acid type polymeric surfactants, and polyoxyethylene alkyl phosphates.

It is sufficient to use the Raney nickel catalyst in an amount of 0.sg to 5 g per 1 mole of azoxy.

The reaction is carried out at a reaction temperature ranging from 20°C to 100°C, but particularly good results are obtained at a reaction temperature of 50°C to 80°C.

From the viewpoint of safety, hydrazine hydrate is desirably 80% or less, and 60% to 40% is effective. The appropriate amount of hydrazine to be used is 1.1 to 1.3 moles per mole of azoxy.

Azoxy compounds generally have the following formula.

and X is -H, -CΩ, -OCH, or -C
H, and the positions are 2.3.4.2', 3' and 4'.

In addition to hydrazine hydrates, hydrazine salts such as neutral hydrazine sulfate, hydrazine sulfate, or hydrazine hydrochloride, which liberate hydrazine under alkaline conditions, can also be used.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 2.2'-dimethylazoxybenzene 45.2g, water 1
07 g, 12.5 g of flaked caustic soda and 0.3 g of surfactant sodium alkylnaphthalene sulfonate in a 300+ equipped with a reflux condenser, stirrer, thermometer and dropping funnel.
Charge ++1 into a four-loop flask and raise the temperature to 60°C. Next, Raney nickel (Yoken NDT-68Wet) 1
, and 19.7 g of 60% hydrated hydrazine are added dropwise over about 4 hours and 30 minutes. After dropping, 60℃
The filter cake was stirred for 1 hour and 30 minutes, cooled to 30°C, filtered, and the filter cake was thoroughly washed with water and dried in a vacuum desiccator to obtain highly pure 2,2 with a melting point of 150-151°C.
41.3 g of '-dimethylhydrazobenzene was obtained.

Example 2 2.51.6 g of 2'-dimethoxyazoxybenzene, 107 g of water, 12.5 g of flaked caustic soda and 0.3 g of alkylnaphthalene sulfonate as a surfactant,
The same 300 ml four-bottle flask as in Example 1 was charged, and the temperature was raised to 60°C.Next, 1.1 g of Raney nickel, the same as in Example 1, was added, and 19.7 g of 60% hydrated hydrazine was added.
After the completion of 0 drops of g for about 3 hours and 30 minutes,
After stirring at 60°C for 1 hour and 30 minutes, cooling to 30°C, filtering, washing with water, and drying in a vacuum desiccator, the melting point was 1.
47.6 g of high quality 2,2'-dimethoxyhydrazobenzene was obtained at 02-103°C.

Example 3 The same operation as in Example 1 was repeated except that 53.4 g of 2,2'-dichloroazoxybenzene was used as the azoxybenzene. As a result, 49.4 g of high-quality 2,2'-dichlorohydrazobenzene with a melting point of 86 to 87°C was obtained.

effect As described above, according to the method of the present invention.

The following effects can be obtained.

(a) Since the reaction is carried out at normal pressure, no special equipment is required.

(b) By using a surfactant, no alcohol is used, so there is no danger of ignition and explosion due to fire.

(c) Hydrazine hydrate can be used in amounts of 80% or less, and usually 60% or less, so there is no danger of ignition and explosion due to fire.

(d) Hydrazine reacts to produce only water and nitrogen, safe and harmless substances, so there is no risk of environmental pollution.

(e) Since the reaction temperature is 100° C. or lower and is usually carried out at 60° C. or lower, there is no risk of blowing out due to vapor pressure or the like.

(F) The product can be easily separated because there is little generation of aniline as a side reaction, and the reaction by-products (reducing agent changes) are only water and nitrogen (gaseous).

(g) Since no solvent is used and the catalyst is an inexpensive nickel-based catalyst, it can be obtained in high yield and purity, so the cost is very low.

Claims (1)

[Claims] 1. An aromatic azoxy compound having the following general formula, ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (X represents -H, -Cl, -OCH_3 or -CH_3), hydroxide or alkaline earth metal hydroxide, suspended in water and a small amount of surfactant, add Raney nickel catalyst,
A method for producing an aromatic hydrazo compound, which comprises gradually adding hydrazine dropwise to reduce the aromatic hydrazo compound at normal pressure.