JPS60136574A - Production of hexahydrotriazine compound - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as a catalyst for producing urethane foams, curing agent for epoxy resins, etc., in high yield and selectivity, by reacting o- or p-anisidine with formaldehyde in the presence of an inert hydrocarbon solvent and an alkali. CONSTITUTION:1mol o- or p-anisidine is reacted with 0.9-2.0mol, preferably 1.0-1.2mol formaldehyde in the presence of an inert hydrocarbon solvent, preferably xylene and an alkali at <50 deg.C, preferably 20-40 deg.C, and the organic layer of the resultant reaction product solution is separated and washed with water to remove the inert hydrocarbon solvent from the organic layer. Thus, the aimed compound expressed by the formula is obtained. The molar amounts of the solvent and alkali to be used based on 1mol raw material anisidine are 2-3mol range solvent and 0.02-0.1mol range alkali.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to hexahydro! This invention relates to a method for producing a +7 gin compound. More specifically, the present invention relates to a method for producing a desired hexahydrotriazine compound by reacting 0- or P-anisidine and formaldehyde in the presence of an inert carbon 1e hydrogen solvent and an alkali.

Known methods for synthesizing the target compound of the present invention include P
- Anisidine and formaldehyde in the coexistence of hydrochloric acid,
Alternatively, there are only a few reports on a method of reacting in ethanol.

The present inventors have developed a method for producing a desired hexahydrotriazine compound in high yield and high selectivity by reacting O- or P-anisidine and formaldehyde in the coexistence of an inert hydrocarbon solvent and an alkali. In order to find out,
This led to the present invention.

That is, the present invention provides formaldehyde in an amount ranging from 0.9 to 2.0 mol, preferably in a range from 1.0 to 1.2 mol, to 1 mol of O- or P-7 Nisidine by inert carbonization. This is a method of reacting at a temperature not exceeding 50°C in the coexistence of a hydrogen solvent and an alkali.The organic layer of the reaction product liquid is separated, and after washing with water, the inert hydrocarbon solvent is removed from the organic layer. To provide a practical method for producing a hexahydrotriazine compound, in which a desired hexahydrotriazine compound can be obtained in high yield and high selectivity through simpler operations, and reaction conditions can be easily controlled. .

In this method, O- or P-aningine and formaldehyde are reacted in the presence of an inert hydrocarbon solvent and an alkali at a specified molar ratio, as described above. The inert hydrocarbon solvent refers to an aliphatic or aromatic hydrocarbon, and specific examples include hecan, heftano, benozeno, toluene, and xylene, of which xylene is preferably used. By coexisting an inert hydrocarbon solvent in the reaction system, an increase in the viscosity of the reaction solution that occurs as the reaction between O- or P-anisidine and polardehyde progresses is suppressed,
K has the effect of accelerating the reaction, making it easier to separate the target product after the reaction is completed, and improving the yield of the target hexahydrotriazine compound. The inert hydrocarbon solvent is usually used in an amount ranging from 2 to 6 moles per mole of 0- or P-7 nisidine.

Formaldehyde can be used in an amount ranging from 0.9 to 2.0 mol per 1 mol of 0- or J]-aningine, particularly preferably 1. [It is in the range of J ~ 1.2 mol, and if it is less than the lower limit, the yield of hexahydrotrianone te h Qh, which is a heavy substance, will be greatly reduced, and the subsequent liquid separation operation will be difficult, and after the recovery of the solvent , unreacted O- or P-
It becomes necessary to recover even anisidine. On the other hand, if too much is used, there is no effect, and the formaldehyde concentration in the waste liquid increases, necessitating more cleaning operations. Formaldehyde is used in the form of an aqueous solution, ie, formalin, and formaldehyde preferably contains a stabilizer, especially one with a low methanol content. This methano-7 acts as an interlayer transfer agent in O- or P-anisidine and formaldehyde solution operations and impairs the liquid state of the reaction mixture. Therefore, it is sufficient to use formalin which has a methanol content of 1 to 2% by weight and does not generate floating substances such as precipitates at room temperature F, and an aqueous solution with a formaldehyde concentration of 20 to 40% by weight is suitable. If it is less than 20%, the capacity of the reaction system will increase, which is not preferable.

The alkali used in the method of the present invention is O-
Or directly involved in the reaction between P-anisidine and polardehyde and lr. The hexahydrotriazine compound, which is a lj-like substance, promotes the desired reaction. It can be obtained with high yield and high selectivity. The alkali used here means a hydroxide or carbonate of an alkali metal or an alkaline earth metal, and specifically includes sodium hydroxide, sodium carbonate, calcium hydroxide, calcium carbonate, etc. I can do it. These may be added to the reaction system in solid form or in the form of an aqueous solution. The amount of alkali added is
Although it depends on the amount of water in the reaction system, in order to prevent unreacted O- or P-anisidine from remaining in the reaction system, it is usually 0 or 0 based on 1 mole of raw material O- or P-anisidine.
It is used in amounts ranging from 2 to 0.1 mol.

The reaction between 0- or 11P-anisidino and polardehyde is an exothermic reaction, and the temperature within the reaction system must be controlled so as not to exceed 50°C. Temperature control within the reaction system may be appropriately performed by dropping formalin and/or removing heat, and a more suitable reaction temperature is 2 [J0
~40°C.

The reaction product liquid obtained by the method of the present invention is an organic solution layer (oil layer) containing the target hexahydrotriazine compound NN \ /' represented by the following formula, and an aqueous solution in which alkali, unreacted formaldehyde, etc. are dissolved. It consists of a layer (aqueous layer), and the inner layer is easily separated.

An oil layer is separated from this reaction product, washed with water, and finally the inert hydrocarbon used as a solvent is distilled off to obtain the desired hexahydrotriazine compound. ) The hexahydrotriazine compound obtained in this way is crystalline at room temperature, and has six hexachloronitrogen atoms in the molecule.
As a ring-membered compound, it is used for various purposes such as catalysts for various urethane foams, curing agents and curing accelerators for epoxy resins, paint stabilizers, rubber latex curing agents, electrode protectants, and as octopus retentive agents and rust preventive agents. and furthermore, 6
It can also be used as a raw material for the synthesis of other chemicals by taking advantage of the reactivity of the amino group.

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

・Example O - Aningin 125g (1 mol) and Metaxyleph
250 g and 4 g (0.025 mole as sodium hydroxide) of a 25% sodium hydroxide aqueous solution were added dropwise with a stirrer, a thermometer, and a cooler (=J).
Pour into a 4th girder flask and bring to a boiling point of 25.6 while stirring.
125 g (1.05 mol) of a formaldehyde aqueous solution (containing 1% by weight of methanol as a stabilizer) having a weight of 91)'a degree was dripped into the reactor from the dropping funnel over 0.5 hours. The reaction temperature during the dropwise addition was maintained at 40° C., and the reaction was continued at that temperature for 5 hours with stirring at 437°C even after the dropwise addition was completed. After the reaction is complete,
Separate the organic layer and water. Add 10 L of water to the organic layer.
After adding 0g of
The layers have been divided. The degree of vacuum from this organic layer was 10 ter.
The continuous components were distilled off under conditions of m Hg' and a maximum temperature of the distiller of 100°C.

1.5.5” tris(2-methoxyphenyl)hexahydrotriazine was obtained as distillation residue, and the yield was 1.
It was 65g. This yield corresponds to a theoretical value of 10096 based on anisidine.

The physical properties of the product obtained by recrystallizing the cold-crystallized bottom residue from ethanol were as follows.

Melting point ("C) 86.5℃

Claims (1)

[Claims] O- or P-7 nisidine and 9 to 2.0 mol of formaldehyde per 1 mol of said aningine in the coexistence of an inert hydrocarbon solvent and an alkali at a temperature not exceeding 50°C. A method for producing a hexahydrotriazine compound represented by the general formula, which comprises causing a reaction.