CN115417790A - Novel azo foaming agent and synthesis method thereof - Google Patents

Abstract

式Ⅰ中，n＝1‑13。The invention provides a new type of azo foaming agent and its synthesis method, which has the general structural formula shown in formula I: the azo foaming agent of the present invention has good foaming performance and does not produce harmful components. The preparation method adopts direct coupling Nitriding method, a new type of azo foaming agent is synthesized, the synthesis method is simple and economical, and has extremely high application value.

In Formula I, n=1-13.

Description

A class of novel azo blowing agent and its synthetic method

technical field

The invention relates to a novel azo foaming agent and a synthesis method, belonging to the technical field of organic chemical synthesis.

Background technique

Foaming agents, as important chemical products, are widely used in food additives, household and building insulation materials, and cold chain logistics, and have great market demand. Therefore, the synthesis of new foaming agents is of great significance.

The foaming agent can be evenly dispersed in the resin, decomposed by heat, and has many excellent properties such as heat preservation, heat insulation, sound insulation, shockproof, light weight, strong elasticity and electrical insulation. There are many types of foaming agents, mainly divided into organic foaming agents (azo compounds, sulfonyl hydrazide compounds and nitroso compounds, etc.) and inorganic foaming agents (carbonates, water glass, silicon carbide and carbon black, etc.) . Among them, azo compounds are a large category of organic blowing agents, with many types, such as azodicarbonamide (referred to as blowing agent AC), diisopropyl azodicarboxylate (referred to as blowing agent DIPA), azo Diisobutyronitrile (ABIN for short), etc., are widely used in the fields of PE, PVC, PS, PP, ABS and other materials. The decomposition products of azo foaming agents are non-toxic, odorless, and non-polluting, and the bubbles produced are uniform and dense, and can be added to rubber products. Then, by changing the type and quantity of the foaming agent, the expansion rate of the rubber can be increased, and the crosslinking density of the vulcanized rubber can be reduced, thereby improving the mechanical properties of the rubber product.

At present, the synthesis of azo blowing agents is mainly through condensation and oxidation. The industrial synthesis method is relatively simple. The synthesis process mostly adopts the strategy of initially synthesizing hydrazine compounds and then oxidizing them. The reaction conditions are harsh and polluting. Disadvantages such as strong sex and danger.

In view of the huge market potential of azo-based blowing agents, it is urgent to develop a new azo-based blowing agent with low cost and simple synthesis method and its synthesis method.

Contents of the invention

Aiming at the deficiencies of the prior art, the invention provides a new type of azo blowing agent and a synthesis method.

The azo foaming agent of the invention has good foaming performance and does not produce harmful components.

The method of the invention adopts the direct azoization method to synthesize a novel azo foaming agent, the synthesis method is simple and economical, and has extremely high application value.

The present invention is achieved through the following technical solutions:

A new type of azo blowing agent, having the general structural formula shown in formula I:

In formula I, n=1-13,

R is hydrogen, alkyl, alkenyl, aryl, fluorine, chlorine, bromine, iodine, trifluoromethyl, sulfur trifluoromethyl, oxytrifluoromethyl, carboxyl, ester, amido, acid chloride, sulfonate One of acyl, sulfonate, indolyl, and carbazolyl.

Preferably according to the present invention, aryl is substituted phenyl, substituted naphthyl, substituted aromatic heterocycle.

According to the present invention, the synthetic method of above-mentioned novel azo compound, the steps are as follows:

Dissolve compound a and base in solvent A, then pass through chlorine gas, stir for reaction, after the reaction, extract with dichloromethane and water, and distill off the solvent under reduced pressure to obtain the target compound.

According to the present invention, preferably, compound a is methyl 1-aminocyclohexane-1-carboxylate, ethyl 1-aminocyclohexane-1-carboxylate, isopropyl 1-aminocyclohexane-1-carboxylate, 1-Aminocyclohexane-1-carbonitrile or 1-aminocyclopentane-1-carboxylate methyl ester.

Most preferably, compound a is methyl 1-aminocyclohexane-1-carboxylate.

According to the present invention, preferably, the solvent A is dichloromethane, toluene, acetonitrile, tetrahydrofuran, 1,2-dichloroethane, ethyl acetate, methanol, ethanol or water.

Most preferably, the solvent A is water.

According to the present invention, preferably, the molar ratio of compound a to chlorine is 1:(1.0-5.0).

Further preferably, the molar ratio of compound a to chlorine is 1:(2.0-3.0).

Most preferably, the molar ratio of compound a to chlorine is 1:2.5.

According to the present invention, preferably, the base is sodium hydroxide, sodium carbonate, pyridine, sodium bicarbonate or triethylamine.

Most preferably, the base is triethylamine.

According to the present invention, preferably, the molar ratio of compound a to base is 1:(1-5).

Most preferably, the molar ratio of compound a to base is 1:2.

According to the present invention, preferably, the reaction temperature is 0-50°C.

Further preferably, the reaction temperature is 20-40°C.

Most preferably, the reaction temperature is 25°C.

According to the present invention, preferably, the reaction time is 1-24 hours.

Further preferably, the reaction time is 10-15 hours.

Most preferably, the reaction time is 12 hours.

The synthetic route of the present invention is shown in following formula II:

Technical characteristics and advantages of the present invention:

1. The present invention successfully synthesizes a new type of azo foaming agent by using cheap primary amine compounds and direct azoization method, which has great application value; the raw materials are cheap, the cost is low, it can be carried out at room temperature, and the energy consumption is low. Low, low equipment requirements, with strong industrial production value.

2. The present invention adopts the direct azoization method to synthesize a new type of azo foaming agent. Compared with the current method of synthesizing the azo foaming agent by initially synthesizing hydrazine compounds and then oxidizing the strategy, the method of the present invention The reaction conditions are mild (not sensitive to air and water, etc.), the production process is simple, the production profit margin is large, and it has the advantages of better environmental friendliness.

3. The novel azo foaming agent synthesized by the present invention has better foaming performance and does not produce harmful components, and has great application prospects in materials such as rubber and plastics.

Description of drawings

Fig. 1 is the ¹ H-NMR spectrogram of the 1-aminocyclohexane-1-formic acid methyl ester that embodiment 1 makes;

Fig. 2 is the ¹³ C-NMR spectrogram of the 1-aminocyclohexane-1-methyl carboxylate that embodiment 1 makes;

Figure 3 is the ¹ H-NMR of 1,1'-(diazene-1,2-diyl)(E)-bis(cyclohexane-1-carboxylate) dimethyl ester prepared in Example 2 spectrogram;

Figure 4 is the ¹³ C-NMR of 1,1'-(diazene-1,2-diyl)(E)-bis(cyclohexane-1-carboxylate) dimethyl ester prepared in Example 2 spectrogram;

detailed description

The present invention will be further described below through specific examples, but not limited thereto.

Example 1

Preparation of methyl 1-aminocyclohexane-1-carboxylate:

Add thionyl chloride (40mmol, 2.9mL) into a solution of 1-amino-1-cyclohexylcarboxylic acid (20mmol, 2.86g) in methanol (50mL), stir and react at 25°C for 12 hours, after the reaction is complete, Evaporate and concentrate to remove the solvent and excess thionyl chloride, then extract with dichloromethane and saturated sodium bicarbonate solution, and concentrate the organic phase to obtain the compound 1-aminocyclohexane-1-carboxylic acid methyl ester as a light yellow oil. The yield is 95%. The synthetic route is shown in the following formula III.

Figure 1 shows the ¹ H-NMR spectrum of the compound 1-aminocyclohexane-1-carboxylic acid methyl ester, and Figure 2 shows the ¹³ C-NMR spectrum.

NMR data:

¹ H NMR (500MHz, CDCl ₃ ): δ3.68(s,3H),1.89(t,J＝9.5Hz,2H),1.66–1.57(m,2H),1.52(s,2H),1.48–1.40 (m,5H),1.36(td,J=10.3,9.0,2.9Hz,1H);

¹³ C NMR (126 MHz, CDCl ₃ ): δ 177.9, 57.4, 52.1, 35.5, 25.5, 22.0.

Example 2

Synthesis of 1,1'-(diazene-1,2-diyl)(E)-bis(cyclohexane-1-carboxylate) dimethyl ester

Chlorine (50mmol) was passed into 1-aminocyclohexane-1-carboxylic acid methyl ester (20mmol, 3.14g) and triethylamine (40mmol, 5.6mL) in water (20mL), and the reaction was stirred at 25°C for 12 Hours, the reaction was over, extracted with dichloromethane and water, and concentrated the organic phase to obtain the compound 1,1'-(diazene-1,2-diyl)(E)-bis(cyclohexane-1-carboxy Acid acid) dimethyl ester is a white solid with a yield of 80%. The synthetic route is shown in the following formula IV.

The ¹ H-NMR spectrum of compound 1,1'-(diazene-1,2-diyl)(E)-bis(cyclohexane-1-carboxylate) dimethyl ester is shown in Figure 3, ¹³ C - The NMR spectrum is shown in Figure 4.

NMR data:

¹ H NMR (500MHz, CDCl ₃ ): δ3.64(s,6H),2.04–1.92(m,8H),1.67–1.61(m,4H),1.54–1.39(m,8H);

¹³ C NMR (126 MHz, CDCl ₃ ): δ 172.6, 79.4, 51.8, 32.0, 25.3, 22.3.

Example 3

With the preparation method described in embodiment 2, the difference is:

1-aminocyclohexane-1-carboxylic acid methyl ester was replaced by 1-aminocyclohexane-1-carboxylic acid ethyl ester, and other parameters and conditions were carried out as in Example 2.

Example 4

With the preparation method described in embodiment 2, the difference is:

Replace methyl 1-aminocyclohexane-1-carboxylate with isopropyl 1-aminocyclohexane-1-carboxylate, and carry out according to Example 2 for other parameters and conditions.

Example 5

With the preparation method described in embodiment 2, the difference is:

1-aminocyclohexane-1-methyl carboxylate was replaced by 1-aminocyclohexane-1-carbonitrile, and other parameters and conditions were carried out as in Example 2.

Claims (10)

1. A new type of azo blowing agent, having the general structural formula shown in formula I:

In formula I, n=1-13, R is hydrogen, alkyl, alkenyl, aryl, fluorine, chlorine, bromine, iodine, trifluoromethyl, sulfur trifluoromethyl, oxytrifluoromethyl, carboxyl, ester, amido, acid chloride, sulfonate One of acyl, sulfonate, indolyl, and carbazolyl. 2. A class of novel azo blowing agent according to claim 1, characterized in that the aryl group is a substituted phenyl group, a substituted naphthyl group, a substituted aromatic heterocycle. 3. the synthetic method of novel azo compound described in claim 1, the steps are as follows: Dissolve compound a and base in solvent A, then pass through chlorine gas, stir for reaction, after the reaction, extract with dichloromethane and water, and distill off the solvent under reduced pressure to obtain the target compound. 4. preparation method according to claim 3 is characterized in that, compound a is 1-aminocyclohexane-1-formic acid methyl ester, 1-aminocyclohexane-1-formic acid ethyl ester, 1-aminocyclohexane Alkane-1-carboxylic acid isopropyl ester, 1-aminocyclohexane-1-carbonitrile or 1-aminocyclopentane-1-carboxylic acid methyl ester, preferably, compound a is 1-aminocyclohexane-1-carboxylic acid methyl ester. 5. the preparation method according to claim 3, is characterized in that, described solvent A is dichloromethane, toluene, acetonitrile, tetrahydrofuran, 1,2-dichloroethane, ethyl acetate, methanol, ethanol or water , preferably, the solvent A is water. 6. The preparation method according to claim 3, characterized in that the molar ratio of compound a to chlorine is 1:(1.0-5.0). 7. The preparation method according to claim 3, characterized in that the molar ratio of compound a to chlorine is 1:(2.0-3.0). 8. The preparation method according to claim 3, wherein the molar ratio of compound a to chlorine is 1:2.5. 9. preparation method according to claim 3, is characterized in that, described alkali is sodium hydroxide, sodium carbonate, pyridine, sodium bicarbonate or triethylamine, and the mol ratio of compound a and alkali is 1:(1 -5), the reaction temperature is 0-50°C, and the reaction time is 1-24 hours. 10. preparation method according to claim 3 is characterized in that, described alkali is triethylamine, and the mol ratio of compound a and alkali is 1:02, and reaction temperature is 20-40 ℃, and the reaction time is 10. -15 hours.

Images