JPH03184942A - 1,3-diamino-2,4-diisopropylbenzene and production thereof - Google Patents

Abstract

NEW MATERIAL:1,3-Diamino-2,4-diisopropylbenzene. USE:A raw material for isocyanates, epoxy resins, bismaleimides etc., or a curing agent giving moderate curing rate esp. when used as a curing agent for urethane RIM. PREPARATION:A 3,5-diisopropyl-1,2-dihalogenobenzene selectively prepared by diisopropylation between (A) an o-dihalogenobenzene and (B) an isopropyl halide, propylene or isopropanol is put to dinitration followed by reduction- dehalogenation, thus easily obtaining the objective 1,3-diamino-2,4- diisopropylbenzene in high efficiency. When the present compound is used for urethane RIM, films with excellent physical properties can be produced in good formability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to 1,3-diamino-2,4-diisopropylbenzene and a method for producing the same.

This aromatic cyanide can be used as a raw material for isocyanates, epoxy resins, bismaleimides, and the like. Further, it has various uses as a curing agent, for example, it can be used as a curing agent for isocyanates, and it can also be used as a curing agent for epoxy resins and bismaleimides.

[Conventional technology]

The 1,3-cyano-2,4-diisopropylbenzene and the method for producing the same of the present invention were newly discovered by the present inventors.

Curing agents for the isocyanates mentioned above, especially urethane RIM (Reaction Injection M
The aromatic cyamines used for 4.4″-diaminodiphenylmethane (M
DA), 2,4 (or 2,6)-diamino-3,5-
Examples include diethyltoluene (DETDA) and 2.4 (or 2.6)-diamino-3 (or 5) -tert-butyltoluene (tBuTDA).

Conventionally, aromatic cyagons are generally synthesized by a nitration-reduction reaction of Hensen derivatives. However, according to this method, during the first nitration reaction, it is difficult to introduce a nitro group only at the desired position due to the orientation of the substituent on Hensen and steric effects, and in many cases several types of isomers are present. It becomes a mixture of bodies. For example, 1,3 diamino-24-diisopropylhenzene synthesized in the present invention also
It is hardly produced by the nitration-reduction reaction of m-diisoprobylhenzene, and the isomer 1,3
, 6-diisopropylbenzene is obtained as the main product (A, Newton; Journal of American
Chemical Psychiatry 65S2434 pages (197
3) ).

[Problem to be solved by the invention]

When aromatic diamino is used as various curing agents, especially when used for urethane RIM, it is necessary to control the reactivity of diamino by steric effects of substituents, etc. To this end, methods have been used to introduce an alkyl group into an aromatic cyanogen and control the reactivity by controlling the substitution position and steric effect. However, it cannot be said that the aromatic cyanide currently used satisfies the above-mentioned problems. For example, when a methyl group or an ethyl group (DETDA) is introduced into an aromatic diamine, the reactivity is high and the moldability is hindered. It is bulky and monobutyl group (t-B
When uTl)A) or the like is introduced, curing is insufficient due to low reactivity, and the surface heat properties of the molded product are reduced. Therefore, the present inventors selected an isopropyl group as the alkyl group and considered controlling the reactivity by its steric effect. When introducing an alkyl group into an aromatic cyanodane to control its reactivity, it is necessary to substitute the alkyl group at the ortho position of the adane in order to suppress the reactivity of the adane.

However, as described above, it is difficult to selectively introduce an agono group into a position affected by the steric action of an alkyl group by the usual nitration-reduction reaction of alkylbenzene.

[Means to solve the problem]

The present inventors conducted intensive studies to solve the above-mentioned problems, and as a result, completed the present invention.

That is, the present invention provides 3,5-
1, characterized in that dinitration and reduction-dehalogenation of diisopropyl-1,2-dihalogenohenzene;
The present invention relates to 3-diamino-2,4-diisopropylhenzene and a method for producing the same.

The characteristics of the 1,3-cyamino-2,4-di-1-fluoropyrhenzene of the present invention are that it can be used as a hardening agent, especially urethane RIrI.
When used as a curing agent, it exhibits moderate reactivity compared to known diamines used in RIM formulations (see usage examples).

The characteristics of the production of cyanogen derivatives of the present invention are 1.3-
In order to selectively carry out the nitration reaction at the 2.4-position of diisopropylbenzene, a halogen group that can be removed by a reduction reaction is introduced in advance at the 5.6-position.

Hereinafter, a specific method for producing 1,3-diamino-2,4-diisopropyrhenzene of the present invention will be explained.

The intermediate 3,5-diisopropyl l,2-dihalogenobenzene can be prepared by reacting ortho-dihalogenobenzene with isopropyl halide, isopropyl alcohol, or propylene in the presence of an acid catalyst. In this reaction, when an isopropylating agent is used in a 2 molar ratio, a mixture of monoisopropyl, diisopropyl, and triisopropyl compounds is obtained. When these mixtures undergo a rearrangement reaction in the presence of aluminum halide, the dialkyl form 3,5-diisopropyl-
Ortho-dihalogenobenzene is the main product. Thus, we have newly discovered that 3.5-diisopropyl-1,2-dihalogenobenzene is selectively produced by the diisopropylation reaction of ortho-dihalogenobenzene.

As the ortho-dihalogenobenzene, ortho-difluorobenzene, ortho-dichlorobenzene, ortho-dibromohenzene, ortho-shortbenzene can be used, and ortho-dichlorohenzene is used industrially.

Furthermore, the isopropyl halides used as the isopropylating agent include isopropyl chloride, isopropyl bromide, and isopropyl fluoride. Other isopropylating agents include isopropyl alcohol and propylene.

The amount of these isopropylating agents to be used with respect to the raw material ortho-dihalogenobenzene may be 1.8 to amol ratio, preferably 2 to 2.5 mol ratio.

As the acid catalyst in this alkylation-transfer reaction, it is most preferable to use aluminum chloride or aldonium bromide. The amount of the catalyst to be used is 0.5 to 50% by weight, preferably 0.5 to 10% by weight, based on the dihalogenobenzene as the raw material.

In addition, if the alkylation reaction and rearrangement reaction are carried out stepwise,
There is no problem in using catalysts in combination.

When using isopropyl halide as an alkylating agent, in addition to alkyl chloride and alkyl bromide, ordinary Fr1delCrafts can be used as an alkylation catalyst.
Catalysts such as iron chloride, zinc chloride, tin chloride, titanium tetrachloride, etc. can be used. The amounts of these catalysts used are the same as described above.

Further, when isopropyl alcohol or propylene is used as the alkylating agent, a protic acid or a mixed catalyst of a protic acid and a Lewis acid can be used as the catalyst. At this time, as the protonic acid, fluorine, sulfuric acid, phosphoric acid, or an inorganic acid or an organic acid such as those used in ordinary alkylation can be used. The amount of these catalysts to be used is 0.5 to 5 equivalents, preferably 1 to 3 equivalents, based on the dihalogenobenzene starting material.

As the transfer reaction catalyst, it is desirable to use aluminum chloride or aluminum bromide. The amount of catalyst used is 0.5 to 50% by weight, preferably 0.5 to 10% by weight based on the raw material.

The reaction temperature for alkylation is -10 to 100°C, preferably 0 to 40°C.

Specifically, when using an alkyl halide or isopropyl alcohol as an alkylating agent, the catalyst is added to ortho-dihalogenobenzene and then the alkylating agent is added dropwise, or the alkylating agent is added dropwise to ortho-dihalogenobenzene and the alkyl A catalyst may be added to the mixture of agents. When propylene is used as the alkylating agent, a closed reactor is used, and after adding a catalyst to ortho-dihalogenobenzene, propylene is injected to carry out the reaction. In either case, the reaction proceeds rapidly and is completed in about 1 hour.

The temperature of the rearrangement reaction is 0 to 100°C, preferably 10 to 100°C.
60°C is good. If the reaction temperature is too low, the transition will be slow; if the reaction temperature is too high, halogen atoms will be transferred and by-products will be produced. The time required for metastasis is about 1 to 20 hours.

After the reaction is completed, the reaction solution is neutralized, washed with water, and then distilled to obtain the intermediate 3,5-diisopropyl 1,2-dihalogenobenzene. Moreover, there is no problem in using the crude mixture after the reaction for nitration as it is.

The method for producing the intermediate dinitro compound by nitrating 3.5-diisopropyl-1,2-dihalogenobenzene is as follows:
Conventional nitrating agents can be used. As a nitrating agent,
Mixed acids, fuming nitric acid, nitric acid-acetic acid, and other known nitrating agents can be used.

Using these nitrating agents, the reaction is carried out as follows.

In other words, when nitrating with fuming nitric acid, 3
~12 times the molar amount is used. Further, when nitrating with a mixed acid, a mixed acid consisting of a combination of nitric acid or a nitrate such as sodium nitrate or potassium nitrate and concentrated sulfuric acid is used. At this time, add nitric acid or nitrate: concentrated sulfuric acid to the raw material at 2.2 to 5
: Used in a molar ratio of 6 to 10.

The reaction temperature during dinitration is 50 to 120°C1
It is desirable to carry out preferably at 50 to 80°C. If the reaction temperature is too low, dinitration progresses slowly and is difficult to complete. On the other hand, if the reaction temperature is too high, side reactions such as iso-nitration and oxidation of isopropyl groups occur simultaneously.

The reaction procedure may be either dropping the raw material into a nitrating agent or dropping the nitrating agent onto the raw material. When a mixed acid is used as a nitrating agent, either a pre-prepared mixed acid may be used, or the raw material and one acid may be mixed, and then the other acid may be added dropwise.

After the reaction is completed, the reaction solution is diluted with ice water to precipitate crystals. If this is filtered and washed with water, the dinitro intermediate is obtained.

The method for reductive halogenation of the obtained dinitro form is as follows:
A method for reducing an ordinary nitro group to an amino group (for example, New Experimental Chemistry Course, Volume 15, Oxidation and Reduction [■], Maruzen (19
77) ) can be applied, but catalytic reduction is industrially preferred.

As the catalyst used for catalytic reduction, commonly used metal catalysts such as nickel, palladium, platinum, rhodium, ruthenium, cobalt, and copper can be used, and palladium is industrially useful. Although these catalysts can be used in the metal state, they are usually used by being attached to the surface of a carrier such as carbon, barium sulfate, silica gel, or alkali, and nickel, cobalt, copper, etc. are used as Raney catalysts. used. The amount of catalyst used is 0.01 to 10% by weight as metal based on the dinitro form of the raw material.
Usually, when used in a metal state, the range is 2 to 2.
8% by weight, 0.1-5% by weight when supported on a carrier
is within the range of

In the method of the present invention, dehalogenation is carried out as hydrogen halide, and the dehydrohalogenating agent used for this is an alkali metal or alkaline earth metal oxide, hydroxide, carbonate, bicarbonate. Salt, or ammonia or organic ammoniums.

Examples include sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium oxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonia, and triethylamine. The amount of the dehydrohalogenating agent used is usually 1 to 2 equivalents relative to the halogen atom.

The reaction solvent is not particularly limited as long as it is inert to the reaction (alcohols such as methanol, ethanol, isopropyl alcohol, glycols such as ethylene glycol and propylene glycol, diethyl ether, dioxane, tetrahydrofuran, methyl cellosolve, etc.) ethers are used.In some cases, hexane,
Aliphatic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as henzene, toluene, and xylene, esters such as ethyl acetate and butyl acetate, and aprotic polar solvents such as N,N-dimethylformamide, N- Methylpyrrolidone and the like can also be used.

If the reaction progresses slowly when using a reaction solvent that is immiscible with water, the reaction can be accelerated by adding a phase transfer catalyst such as a quaternary ammonium salt or a quaternary phosphonium salt.

The amount of solvent to be used is not particularly limited as it is sufficient to suspend or completely dissolve the raw materials, but it is usually used 0.5 to 10 times the weight of the raw materials.

The reaction temperature is not particularly limited. Generally 20-200
'C range, especially 20-100°C range is preferred.

Moreover, the reaction is carried out in the range of normal pressure to 50 atm.

The procedure for carrying out the reduction-hypohalogenation reaction is to perform the reaction by adding a dehydrohalogenating agent in advance, or to perform the dehalogenating reaction by adding a dehydrohalogenating agent after reducing the nitro group. . In either case, the reaction proceeds smoothly;
The desired 1,3-diamino-2,4-diisopropyrhenzene can be produced.

However, in the former method, depending on the dehydrohalogenation agent used, it may react with the dinitro compound of the raw material, so the latter method is preferable.

The progress of the reaction can be monitored by hydrogen absorption or liquid chromatography analysis.

The reaction solution obtained by the above method is filtered or extracted to remove the catalyst and inorganic salt. After concentrating the obtained solution, the desired 1,3 diamino-24-diisobrobyrhenzene can be obtained by distillation or crystallization as an amine hydrochloride.

[Effect]

The 1,3-cyano-2,4-diisopropylbenzene of the present invention is an aromatic diamino that can be used for various industrial purposes. This compound is a hitherto unknown aromatic diamino and can be easily provided by the method of the present invention.

Hereinafter, the present invention will be explained in detail with reference to Examples.

〔Example〕

A reaction flask equipped with a stirrer, thermometer and condenser was charged with O.
- 44.1 g (0.3 mol) of dichlorobenzene was charged, cooled to 5°C, and 0.5 g of aluminum chloride was added. To this, 48 g of isopropyl chloride (0,
611 mol) was added dropwise over 30 minutes. When the dropwise addition of isopropyl chloride is started, hydrogen chloride gas begins to be generated.

After dropping, the temperature was raised to room temperature and stirred for 15 hours. After the reaction was completed, 30 ml of a 5% aqueous sodium hydroxide solution was added to neutralize the mixture, and the aqueous layer was separated, and the solid and plate layers were washed with 50 ml of water. The obtained organic layer was distilled under reduced pressure to obtain a colorless liquid 3,5-
Diisopropyl-〇-dichlorobenzene was obtained.

Yield 58.9g (yield 74%, purity 87%) Boiling point 1
19-120°C (7 mmHg) 48 g (0,181 mo+) of 3.5-diisopropyl-1,2-dichlorobenzene with a purity of 87% thus obtained was heated to 0.
31 g of nitric acid with a specific gravity of 1.52 (0
, 462 mol), 95% sulfuric acid 215 g (2,08
It was added dropwise into the mixed acid of mo+) over 10 minutes. After dropping, the cooling bath was removed and the mixture was stirred at 50°C for 3 hours. After the reaction was completed, the reaction solution was discharged onto crushed ice, and the precipitated solids were collected by filtration. The obtained solid was washed with water until the washing solution became neutral, then slushed with 100 ml of isopropyl alcohol, and dried to give pale yellow crystals of 4,6 dinitro 3.5
-diisopropyl-1,2-dichlorobenzene was obtained.

Yield 41g (yield 71%, purity 99%) Melting point 82~
84°C'H-NMR (CDCl3.TMS) ppmδ:
1.37 (12H, t, 3- and 5-CH
(Another surname,) 2.5-3.5 (2) 1, m, 3
- and 5-CI(CH3)2) elemental analysis value (%
) HNCI calculated value 44.88 4.39 B, 72 2
2.08 analysis value 45.05 4.21 B,
73 21.76 obtained 4,6-sinitro 3.5-
40 g of diisopropyl-1,2-dichlorobenzene
(0,125+++ol) was added to 50 ml of methanol, and further 2 g (5 wt%) of 5%-Pd/C was added. Pressurized reduction was carried out under a hydrogen atmosphere at a reaction pressure of 5 to 23 kg/cm2. When stirring starts, heat is generated and the reaction temperature reaches 6.
The temperature rose to 0'C. Hydrogen absorption stopped approximately 1 hour after the start of the reaction. At this stage, 16.7 g (2.2 eq) of 28.chi.-ammonia water as a dehydrochlorination agent was added, and the reaction was further carried out at a reaction temperature of 50 to 60 DEG C. and normal pressure for 10 hours. After the reaction was completed, Pcl/C was removed from the reaction solution by filtration. After adding 50 ml of toluene to the filtrate and separating the organic phase, it was washed with water. The resulting solution was dried over potassium carbonate, concentrated, and the residue was distilled under reduced pressure to give a yellow liquid.
．． 3-cyagono2,4-diisopropylhenzene was obtained.

Yield 16.8 g (yield 70%, purity 95%) Boiling point 143-145°C (4mmHg)'11-NMR (C
DCl3. TMS) PPmδ: 1.23 (61
1, d, 2- or 44-C3 (Cjjtl)
1. 42 (611, d, 2- or 4-C1
1 (betsuai z) 2.5~3.5 (2H, m, 2-
and 4-CI(CHz)2) 3.53 (411
, br S , NH2X2 )6.15 (III
, d, 6-11, Jb-s-8,0Hz)
6.80 (Ill, d, 5-H, Js-b
= 8.0 Hz) Elemental analysis value (%) HN Calculated value 74.95 10.48 14.57 Analysis value 74.16 10°24 14.46 Example of use Diamine obtained in Example and commercially available MDA.

DETDA and t-BuTDA were used to compare their reactivity as urethane curing agents. The reaction was carried out by dissolving 0.025 mol of various diamine compounds in dioxypropylene glycol to make 100 parts, adding 0.01 g of dibutyltin laureate as a catalyst to this solution, and adding isocyanate (diphenylmethane diisocyanate and its carbodiimide-modified 12.1 g of a 26% NCO group-containing repolymer obtained by reacting the mixture with tripropylene glycol was added, and the mixture was mixed and stirred.

As a method for expressing reactivity, after performing the above-mentioned mixing and stirring for 5 seconds, thickening was measured using a rheometer (manufactured by Toyo Seiki).

The results are shown in FIG.

〔effect〕

As described above, it has been found that 3,5-diisopropyl-1,2-dihalogenobenzene is selectively produced by the diisopropylation reaction of ortho-dihalogenobenzene. If this material is used as a starting material, normal m-
It is possible to efficiently synthesize 1,3-cyano-2,4-diisopropylbenzene, which is difficult to produce by dinitration-reduction reaction of diisopropylbenzene. The obtained shea honey has low reactivity due to the steric effect of the isopropyl group, and can be used as a curing agent, especially urethane l? When used as a curing agent for IM, it exhibits a moderate curing speed.

As a result, when the present cyan ξ is used for urethane RIM, a film with good moldability and high physical properties can be obtained.

[Brief explanation of drawings]

The first factor shows the thickening curve of urethane using cyamines as a curing agent. In FIG. 1, the symbols are as follows. 19~ ETDA t-BuTDA The siatan of the present invention 4.4''-diaminodiphenylmethane 2,4/2.6-diami2-35-diethyltoluene 2,4/2.6-dia ξ no 315 tre,t- butyltoluene

Claims (1)

[Scope of Claims] 1) 1,3-diamino-2,4-diisopropylbenzene 2) 3,5-diisopropyl-1,2- obtained by reaction of ortho-dihalogenobenzene with isopropyl halide, propylene or isopropanol A method for producing 1,3-diamino-2,4-diisopropylbenzene, which comprises dinitrating dihalogenobenzene and subjecting it to reduction-dehalogenation.