JPS63159362A - Production of methyleneimine compound - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful for instantaneous adhesive, etc., in high quality, stability and yield, by carrying out thermally decomposition of a hexahydrotriazine compound in the presence of a catalyst in a basic gas atmosphere. CONSTITUTION:A methyleneimine compound of formula II can be produced by the thermal decomposition reaction of a hexahydrotriazine compound of formula I (R is alkyl, benzyl, phenetyl, etc.) in the presence of a catalyst in a basic gas atmosphere. The catalyst is e.g. a complex of a metal salt and a compound of formula I, a salt of an inorganic acid and benzylamine or m- xylylenediamine, etc., a synthetic zeolite, etc. The basic gas is e.g. NH3, methylamine, ethylamine, etc., and is directly blown into the reaction system. The objective compound produced by this process can be stably stored for longer time than a compound produced in an inert gas atmosphere and can be handled at normal temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a methyleneimine compound using a hexahydrotriazine compound as a raw material.

[Conventional technology]

When a hexahydrotriazine compound is thermally decomposed in the absence of a catalyst, it produces a methyleneimine compound, but at this time side reactions also occur simultaneously, producing a number of byproducts such as primary and secondary amine compounds, amide compounds, and aldehyde compounds.

In addition, methyleneimine compounds are very unstable compounds, so even if the above impurities and moisture are present, polymerization will occur or the starting material will return to the hexahydrotriazine compound, so it cannot be used without a catalyst. Methyleneimine compounds cannot be obtained in a stable state through thermal decomposition reactions.

Therefore, it is necessary to use a catalyst and select low reaction temperature conditions.

Up until now, the methods for producing methyleneimine compounds have been as follows:
U.S. Patent No. 2.739.679, U.S. Patent No. 2.739, 6
No. 80 and Journal of American Chemical
Society Part 2 (Journal of Amer
ican Chemical 5ociety, Pa
rt It) discloses a method of subjecting a hexahydrotriazine compound to a decomposition reaction using a strong acid or a Friedelta raft catalyst.

Even when the above-mentioned strong acid or Friedel-Crafts catalyst is used, it is not possible to obtain a high-quality, stable methyleneimine compound in high yield.

[Problem that the invention seeks to solve]

An object of the present invention is to improve the problems of the prior art and provide a method for obtaining a high-quality, stable methyleneimine compound at a high yield.

[Means for solving problems]

As a result of extensive research, the present inventors have succeeded in obtaining a high-quality, stable methyleneimine compound in high yield by carrying out the reaction using a catalyst and in a basic gas atmosphere. Successful.

The present invention relates to a method for producing a methyleneimine compound represented by the -i formula (II) from a hexahydrotriazine compound represented by the general formula [I].

CH,=N-R(II) (In the formula, R represents an alkyl group, a benzyl group, an alkyl-substituted benzyl group, a phenethyl group, or an alkyl-substituted phenethyl group.) In the general formula (13 and [■], R represents Examples of the alkyl group include a chain, cyclic or alkyl-substituted cyclic alkyl group having 5 to 15 carbon atoms, such as a chain, cyclic or alkyl-substituted cyclic pentyl group, hexyl group,
Heptyl group, octyl group, decyl group, and dodecyl group are suitable, and the alkyl group in the alkyl-substituted benzyl group and alkyl-substituted phenethyl group has 1 to 4 carbon atoms.
A chain alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group is suitable, and cases in which a plurality of these alkyl groups are bonded to a benzyl group or a phenethyl group are also included.

Typical hexahydrotriazine compounds include 1.
3.5-tris(1-methylheptyl)hexahydrotriazine, 1,3.5-1-ribenzylhexahydrotriazine, 1.3.5-triphenethylhexahydrotriazine, 1,3.5-tris (α-methylbenzyl)
Hexahydrotriazine, 1.3.5-tris(3-methylbenzyl)hexahydrotriazine, 1.3.5-
) Lis(4-methylbenzyl)hexahydrotriazine, 1.3.5-) Lis(4-methylcyclohexyl)hexahydrotriazine, 1.3.5-) Lis(4-methylcyclohexyl)hexahydrotriazine, 1.3 Examples include 5-1-lis(2,3-dimethylcyclohexyl)hexahydrotriazine.

In the present invention, an example of the catalyst used is a complex of a metal salt and a compound represented by the general formula [I].

The metal salt, which is a component of the above-mentioned complex catalyst, is a metal having divalent or trivalent valence electrons (such as copper, iron, nickel, zinc,
Examples include mercury, tin, chromium, cobalt, lead, etc.)
It is obtained from an inorganic acid (for example, hydrochloric acid, bromic acid, iodic acid, sulfuric acid, etc.).

The hexahydrotriazine compound that forms a complex with the above metal salt is a compound represented by the general formula [I], but it does not need to be the same compound as the hexahydrotriazine compound used as a raw material, and in particular 1. 3.5-tribenzylhexahydrotriazine and 1.3.5-)
Licyclohexylhexahydrotriazine is preferred.

Other examples of catalysts that can be used in the present invention include salts of inorganic acids with benzylamine, metaxylylene diamine, etc., and synthetic zeolites.

Further, the catalyst used in the present invention is not limited to the above-mentioned catalyst; that is, the basic gas used in the present invention works effectively even when other catalysts are used.

Examples of the basic gas used in the present invention include ammonia, methylamine, ethylamine, isopropylamine, and dimethylamine.

Among these basic gases, ammonia and methylamine are particularly preferred.

As for how to use the basic gas, it is sufficient to blow it directly into the reaction system.

The separation of the methyleneimine compound from the reaction product liquid can be easily carried out by distillation under reduced pressure, but it is also possible to separate the generated methyleneimine compound by distillation while allowing the decomposition reaction to take place in a reduced pressure distillation apparatus.

[Action and effect]

According to the present invention, a methyleneimine compound of high quality and good stability can be obtained in high yield.

The methyleneimine compounds produced under a basic gas atmosphere according to the invention can be stored stably for a longer period of time than those obtained under an inert gas atmosphere.

Further, according to the present invention, the methyleneimine compound, which is a reaction product, can be handled even at room temperature.

The high-quality methyleneimine compounds obtained by this reaction method are used in instant adhesives, catalysts for various urethane foams, curing agents and curing accelerators for epoxy resins, paint stabilizers, rubber latex curing agents, vulcanization accelerators, and electrode protection. It is extremely important for a variety of applications, including agents, conductive polymers, ion exchange resins, and polymer flocculants.

〔Example〕

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples.

In addition, reference examples 1 to 4 describe preparation examples of the catalysts used in this example.

Reference example 1: 16.2g of reagent grade ferric chloride in 350ml of ethanol? The ethanolcin solution was then filtered, and the filtrate obtained at this time was charged into a 500 ml four-bottle flask equipped with a stirrer, a thermometer, and a condenser.

150ml of 28.6g of 1,3.5-)ribenzylhexahydrotriazine recrystallized and purified with ethanol
of ethanol and then filter the ethanol solution. The filtrate obtained at this time was stirred and heated at 40 to 45°C.
It was added dropwise to the liquid in the 4-hole flask over a period of about 1 hour under conditions C, and the temperature was kept at the same temperature for an additional hour.

Thereafter, the mixture was gradually cooled to around 10''C, and the formed precipitate was filtered off, washed twice with 50 ml of purified ethanol, and then dried under reduced pressure to obtain 34.8 g of a bright yellow powdered catalyst.

Reference Example 2 Except for using 15 g of reagent special grade cupric chloride and 25.5 g of 1,3.5-)licyclohexylhexahydrotriazine recrystallized and purified with ethanol, and setting the reaction temperature to 30°C. The same operation as in Reference Example 1 was performed.

As a result, 13 g of a light green powdered catalyst was obtained.

Reference Example 3 30 g of distilled benzylamine and 30 g of distilled water were placed in a four-bottle flask equipped with a stirrer, a cooler, and a thermometer, and while cooling so that the temperature did not exceed 50'C, 50 g of 20% hydrochloric acid was added. was gradually dropped into the reaction system from the dropping funnel.

Thereafter, the reaction solution was condensed using an evaporator, and the resulting crude crystals of benzylamine hydrochloride were purified by recrystallization twice from methanol.

The obtained plate-like or columnar crystals were dried under reduced pressure, and 22
．． 4 g of catalyst was obtained.

Reference Example 4 Into a fourth flask similar to Reference Example 3, 35 g of metaxylylene diamine purified by distillation and 40 g of distilled water were charged.
47 g of 0% hydrochloric acid was gradually dropped into the reaction system from the dropping funnel.

The reaction conditions and operations were the same as in Reference Example 3.

By the above operation, plate-like or columnar crystals (catalyst) 35.
2g was obtained.

Example 1 1,3.5-) Ribenzylhexahydrotriazine (
65.5 g (purity of 99.9% or higher) and 0.820 g of the complex of ferric chloride and 1.3.5-1-ribenzylhexahydrotriazine obtained in Reference Example 1 were prepared using a thermometer and a distiller. After supplying it to a pear-shaped flask and replacing the inside with dry ammonia gas, under ammonia gas flow, 0.4 mm
140-160°C under reduced pressure conditions of Hg (absolute pressure)
A decomposition reaction was performed to obtain benzylmethyleneimine as a distillate component.

The yield was 57.2 g, 873 mol% of the theoretical yield.
It was equivalent to

The product obtained here was stored as a colorless, transparent, low viscosity liquid in an inert gas-tight container at 0°C for 7 days at 25°C.
C could be stably stored for 24 hours.

Example 2 50 g of 1,3.5-)licyclohexylhexylhexyltriazine (purity 99.9% or higher) and cupric chloride obtained in Reference Example 2 and 1.3.5-1lycyclohexylhexylhexyl 0.44 g of the complex with hydrotriazine was supplied to the same flask as in Example 1, and after replacing the inside with dry ammonia gas, the flask was heated under reduced pressure conditions of 13.5 mmHg (absolute pressure) under a stream of ammonia gas at 95 to 95 mmHg (absolute pressure). A decomposition reaction was carried out at 110"C to obtain cyclohexylmethyleneimine as a distillate component.

The yield was 42.3 g, 846 mol% of the theoretical yield.
It was equivalent to

The product obtained here was stored as a colorless, transparent, low viscosity liquid in an inert gas-tight container at 0°C for 30 days.
It could be stored stably for 5 days at °C.

Example 3 50 g of 1,3.5-tricyclohexylhexahydrotriazine (purity 99.9% or more) and 0.504 g of benzylamine hydrochloride obtained in Reference Example 3 were charged into the same apparatus as in Example 1. , under methylamine gas flow, 13mmHg
A decomposition reaction was carried out at 102 to 115° C. under reduced pressure conditions (absolute pressure) to obtain 40.3 g of clear and colorless cyclohexylmethyleneimine as a distillate.

The reaction yield was 80.6 mol%.

The product obtained here was stored as a colorless, transparent, low viscosity liquid in a sealed container at O'C for 20 days and at 25 °C for 3 days.
It could be stored stably for several days.

Example 4 1,3.5-) Ribenzylhexahydrotriazine (
50 g (purity of 99.9% or higher) and 0.52 g of metaxylylenediamine dihydrochloride obtained in Reference Example 4 were placed in the same apparatus as in Example 1, and heated under a methylamine gas flow to a diameter of 1.9 mm.
135-145°C under reduced pressure conditions of Hg (absolute pressure)
A decomposition reaction was carried out to obtain 40.9 g of clear and colorless benzylmethyleneimine as a distillate.

The reaction yield was 81.8 mol%.

The product obtained here is stored as a colorless, transparent, low viscosity liquid in a sealed container at 0°C for 5 days and at 25°C for 200°C.
It was possible to store it stably over time.

Example 5 50 g of 1,3.5-tris(3-methylbenzyl)hexahydrotriazine (purity 99.9% or higher) and 0.251 g of metaxylylenediamine dihydrochloride obtained in Reference Example 4
g was charged into the same apparatus as in Example 1, and subjected to a decomposition reaction at 140 to 160 °C under reduced pressure conditions of 1.5 m m f (g (absolute pressure)) under a stream of ammonia gas, and a colorless distillate was obtained. Transparent 3-methylbenzylmethyleneimine 3
9.7g was obtained.

The reaction yield was 79.4 mol%.

The product obtained in 22 could be stably stored in a sealed container as a colorless, transparent, low viscosity liquid at 0°C for 7 days and at 25°C for 24 hours.

Example 6 1,3.5-) 75 g of lycyclohexylhexahydrotriazine (purity 99.9% or more) and X-type zeolite 2
g into a pear-shaped flask equipped with a thermometer and a distillation device, and after purging the inside with methylamine gas, decompose it at 110 to 180°C under a reduced pressure condition of 10 mmHg (absolute pressure) under a stream of methylamine gas. The reaction yielded 65.7 g of colorless and transparent cyclohexylmethyleneimine as a distillate.

The reaction yield was 87.6 mol%.

The product obtained here could be stably stored in a sealed container as a colorless, transparent, low viscosity liquid at O'C for 30 days and at 25°C for 5 days.

Comparative Example 1 1.3.5-i-ribenzylhexahydrotriazine (
50 g (purity 99.9% or higher) and 0.453 g of the complex of ferric chloride and 1.3.5-)ribenzylhexahydrotriazine obtained in Reference Example 1 were placed in a pear-shaped flask equipped with a thermometer and a distillation device. After purging the inside with dry nitrogen, a decomposition reaction was carried out at 145 to 165°C under reduced pressure conditions of 1.6 mmHg (absolute pressure) under a nitrogen stream to obtain benzylmethyleneimine as a distillate component.

The yield was 40.3 g, corresponding to 80.6 mol% of the theoretical yield.

The product obtained here was stored as a colorless, transparent, low viscosity liquid in an inert gas-sealed container at 0°C for 1 day at 25°C.
I was able to save it for an hour.

Comparative Example 2 50 g of 1,3.5-tricyclohexylhexylhexahydrotriazine (purity 99.9% or higher), cupric chloride obtained in Reference Example 2, and 1,3.5-tricyclohexylhexahhydrotriazine 0.44 g of the complex was supplied to the same flask as in Example 1, and after purging the inside with dry nitrogen, it was heated to 98% under reduced pressure conditions of 13.5 mmHg (absolute pressure) in a nitrogen stream.
A decomposition reaction was carried out at ~110''C to obtain cyclohexylmethyleneimine as a distillate component.

The yield was 38.5 g, corresponding to 77.0 mol% of the theoretical yield.

The product obtained here was stored as a colorless, transparent, low viscosity liquid in an inert gas-tight container at 0°C for 2 days.
It could be stably stored at 5°C for 3 hours.

Claims (1)

[Claims] When producing a methyleneimine compound represented by the general formula [II] using a hexahydrotriazine compound represented by the general formula [I] as a raw material, in the presence of a catalyst and in an atmosphere of basic gas. A method for producing methyleneimine compounds characterized by reacting with (represents the group)