KR101485545B1 - A Process for the Preparation of Isopropylhydroxylamine - Google Patents

Abstract

The present invention relates to a process for producing isopropylhydroxylamine (IPHA), wherein hydrogen is added to 2-nitropropane at a pressure of 50 to 200 psi at a temperature of 50 to 200 DEG C in the presence of a specific catalyst. The process being characterized in that the reaction time is shortened while improving the yield and selectivity.

Description

A process for preparing isopropylhydroxylamine,

The present invention relates to a process for preparing isopropylhydroxylamine by hydrogenation of 2-nitropropane in the presence of a specific catalyst.

SDD and DEHA are tertiary amine compounds, which are reacted with polymerization terminator and are used as environmental pollutants (carcinogen, polyphenylene sulfide, polyvinylpyrrolidone, polyvinylpyrrolidone, polyvinylpyrrolidone, There is a problem that a nitrosamine, which is a substance which is a substance which is a substance, is generated. Isopropylhydroxylamine is a secondary amine that serves to remove two monomer radicals from the polymerization reaction by providing a one-molecule, two-radical source in the reaction mechanism, which itself is a carcinogenic nitrosamine, Is converted into a safe oxime structure which is not generated. The isopropylhydroxylamine polymerization terminator can be prepared by hydrogenation at a specific temperature and hydrogen pressure in the presence of a palladium / carbon or palladium / alumina catalyst, EDTA (ethylenediaminetetraacetic acid), or a sequestering agent containing an alkali metal salt It proceeds. However, it can be seen that the selectivity is lowered in the form of mono-isopropylamine, which is a byproduct in isopropylhydroxylamine, depending on the amount of catalyst used, the presence of a sequestering agent, the temperature and hydrogen pressure conditions there was. In addition, there is a problem that the yield, selectivity and reaction rate of the reaction differ depending on the manufacturer of 2-nitropropane.

On the other hand, as a conventional patent document for a process for producing hydroxylamine, US Patent Publication No. 05646327 discloses a process for producing a hydroxylamine having various substituents (structure (3)) by using a vinyl group compound (Structure 3) and a substituted alkyl group 1), a method of increasing the selectivity of hydroxylamine without using a neutralizing agent is disclosed.

Structure 1

Structure 2

Structure 3

On the other hand, European Patent Application No. 99202873.8 discloses a process for preparing an antioxidant compound of structure 4 using the epoxide ring opening reaction of structure 5.

Structure 4

Structure 5

US-A-05288907 discloses a process for preparing a storage stable N-alkylhydroxylamine free base, which process comprises the steps of hydrogen pressurization and reaction with a reducing agent such as EDTA, tetrasodium N, N'-ethylene-bis (2- -Methyl-phenyl) -glycine) diethylenetriamine pentaacetic acid, ethylenebis-N, N'- (2-aminomethyl) pyridine-N, N'- diacetic acid, HEDTA, NTA, and N, - (2-hydroxybenzyl) trimethylenediamine-N, N'-diacetic acid and hydrogenating the nitroalkane in the presence of a catalytic amount of a palladium hydrogenation catalyst.

However, there is no mention of the difference in reactivity depending on the raw materials of 2-NP used in the above patent, and the catalysts which are different from each other in reactivity and selectivity due to 2-NP difference, have.

Accordingly, the inventors of the present invention have invented a process for selectively producing 89% or more of a mono-isopropylamine compound produced as a byproduct in 7% or less of isopropylhydroxylamine compound .

Accordingly, it is an object of the present invention to provide a compound which improves the yield, selectivity, and reaction rate in a conventional production process in which the yield, selectivity and reaction rate differ depending on the manufacturer of 2-nitropropane, and a method for producing the same .

The present invention relates to a process for preparing isopropylhydroxylamine by hydrogenation of 2-nitropropane using a primary catalyst, EDTA and a subsidiary catalyst, wherein the solvent of the reaction is a polar organic solvent, Lt; / RTI >

In addition, the present invention is intended to provide a process wherein said by-product is Lewis Acid.

The present invention relates to a process for the preparation of isopropylhydroxylamine, which is characterized in that the reaction time is shortened while improving the yield and selectivity, especially in the presence of a free base used as Lewis Acid The isopropylhydroxylamine compound prepared by the above-mentioned invention can be used as a polymerization terminator in the polymerization of a polymer.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the formula of the product of the present invention, isopropylhydroxylamine.

The present invention is characterized by an isopropylhydroxylamine compound represented by the following formula (1) and a method for producing the same.

[Chemical Formula 1]

Hereinafter, the present invention will be described in detail.

The present invention relates to a process for promoting partial hydrogenation by the addition of hydrogen to 2-nitropropane in the presence of a catalyst, and particularly to a process for producing isopropylhydroxylamine in the presence of palladium / alumina catalyst and EDTA at a yield of 89% , Mono isopropylamine as a by-product to minimize selectivity, and a method for producing the same. The product obtained as the hydrogenation of 2-nitropropane progresses is shown in the following reaction formula (1).

[Reaction Scheme 1]

The yields, selectivities and reaction rates of the compounds prepared by this method can vary depending on the manufacturer of the 2-nitropropane. Accordingly, in the present invention, sodium boron hydride (NaBH ₄ ), lithium boron hydride (LiBH ₄ ), and methyl boronic acid, which are Lewis Acids that can be used as a reducing agent, %, The selectivity and the reaction rate could be improved. By controlling the reaction temperature and the hydrogen pressure, the byproduct mono isopropylamine ratio could be minimized. The final product in the hydrogenation reaction mechanism is the mono isopropylamine due to overaction. In order to obtain the desired intermediate, isopropylhydroxylamine, the reaction temperature, the reaction pressure, the catalyst and the choice of the base catalyst are important and the detailed reaction of the hydrogenation reaction The conditions are described in the Examples. The chemical reaction formula for preparing the isopropylhydroxylamine of the present invention is shown in the following Reaction Scheme 2.

[Reaction Scheme 2]

Hereinafter, the present invention will be described in detail.

The process for preparing an isopropylhydroxylamine compound according to the present invention can be explained by the following reaction.

2-Nitropropane, methanol, palladium catalyst, EDTA, sodium boron hydride (NaBH ₄ ) were added to the autoclave reactor, the reaction temperature was raised to 70 to 120 ° C., the hydrogen pressure was adjusted to 100 to 200 psi, An isopropylhydroxylamine compound represented by the reaction formula 2 can be prepared.

The catalyst used was palladium / alumina and palladium / carbon. The degree of progress of the reaction depends on the amount of the catalyst used. As the amount of the catalyst increases, the rate of reaction increases, but the ratio of mono-isopropylamine, which is a reactant, increases.

The reaction proceeds at a reaction temperature between 70 and 120 ° C. As the reaction temperature increases, the reaction rate increases but the selectivity to mono isopropylamine increases due to the increase in the amount of reactant mono isopropylamine. Hydrogen pressure is in the range of 100 to 200 psi. Hydrogen pressure and the reaction temperature increase as the reaction temperature increases, but the selectivity of the hydrogen is increased due to the increase of isopropylhydroxylamine. [Table 2] Refer to the experimental results.

In addition, the amount of EDTA used as a reference and the reaction progression differ depending on the use. When EDTA is not added, the reaction proceeds more than 60% with Mono-isopropylamine, which is a product. It affects the reactivity depending on the amount added when EDTA is used. When it is used more than 0.2 wt% 2-nitropropane remains and the reaction yield tends to decrease.

Also, depending on the material of the hydrogenation reactor to be used, it affects the reactivity, which can be attributed to the influence of the metal catalyst used in the hydrogenation reaction.

It is an object of the present invention to provide a compound having an improved selectivity of isopropylhydroxylamine produced according to the reaction temperature and the hydrogen pressure as described above and improving the yield and the reaction rate, Main purpose.

As a result of the hydrogenation reaction test by the hydrogenation catalyst, the reactivity was improved as the hydrogenation catalyst amount was increased, but the selectivity was decreased and the mono-isoporpylamine as the reactant was increased. In consideration of the reactivity and selectivity, It was confirmed that the reaction was within 0.4-1.5% of the optimum reaction. [Table 1] Please refer to the experimental results.

Alcohol solvents such as MeOH, EtOH, IPA and the like are used as the solvents for the hydrogenation reaction.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples.

Example  1: 2- Nitropropane  Hydrogenation of isopropylhydroxylamine ( Isopropylhydroxylamine ) Preparation of compound

To 100 g of 2-nitropropane was dissolved 100 g of a methanol solvent, 0.05 wt% of EDTA catalyst, 1 wt% of 5% Pd / Al ₂ O _{3 and} 0.02 wt% of NaBH ₄ were added to 2-nitropropane, Hydrogenation is carried out at 100 psi. The reaction termination is defined as the reaction termination point when the hydrogen pressure is not reduced. After completion of the reaction, GC analysis revealed that the conversion of 2-nitropropane was 97% or more and the yield of isopropylhydroxylamine was 89% or more. There is a difference between the conversion rate and the yield rate depending on the respective reaction conditions, and the exact values are shown in [Table 3].

Table 1 below shows the results of analysis of 2-nitropropane (2-NP, 2-Nitropropan) reactants.

Classification Reaction amount (g) GC content (%) 2-NP ¹⁾ 5% Pd / Al ₂ O ₃ EDTA MeOH MIPA IPHA Acetone
oxime 2-NP IPHA
by-product Reference Example 1 100 ^a 0.4 0.1 100 3.5 92.8 3.20 0 0.50 Reference Example 2 100 ^b 0.4 0.1 100 1.17 22.04 0.79 74.50 1.50 Reference Example 3 100 ^b 0.4 0 100 33.30 35.21 2.58 28.33 0.88 Reference Example 4 100 ^b 0.4 0.05 100 3.49 29.17 1.91 63.41 2.02 Reference Example 5 100 ^b 0.4 0.2 100 1.64 18.40 1.19 76.40 2.37 Reference Example 6 100 ^b 0.6 0.1 100 1.99 34.75 0.79 60.43 2.04 Reference Example 7 100 ^b 0.8 0.1 100 3.15 43.50 1.11 49.76 2.48 Reference Example 8 100 ^b 1.0 0.1 100 4.18 62.10 1.28 30.61 1.84 Reference Example 9 100 ^b 1.5 0.1 100 5.63 73.29 1.84 16.22 3.02

1) Manufacturers a and b are different.

*. Reaction conditions: 100 占 폚, 100 psi, 60 minutes

Table 2 below shows the results of reaction analysis (reaction pressure change) according to reaction conditions.

Classification Reaction conditions GC content (%) Temperature() Pressure (psi) Reaction time
(min) MIPA IPHA Acetone
oxime 2-NP IPHA
by-product Reference Example 10 100 100 60 4.39 63.51 1.83 27.69 2.58 Reference Example 11 100 200 60 12.13 69.51 2.44 14.62 1.30 Reference Example 12 150 100 60 8.33 63..36 1.77 24.91 1.63 Reference Example 13 150 200 60 14.54 73.67 2.92 7.73 1.13

* 5% Pd / Al ₂ O ₃ (1.0 wt%), EDTA (0.05 wt%),

When the reaction temperature and pressure were increased, the reaction conversion was increased but the selectivity was decreased due to the increase of the reactant monoisopropylamine.

Table 3 below shows the result of analyzing the reactants according to the kind of the base catalyst (difference in reactivity according to the kind of the Lewis Acid).

Classification Reaction amount (g) GC content (%) 2-NP 5%
Pd / Al ₂ O ₃ EDTA MeOH The MIPA IPHA Acetone oxime 2-NP IPHA
by-product Comparative Example 100 1.0 0.05 100 0 4.39 63.51 1.83 27.69 2.58 Production Example 1 100 1.0 0.05 100 0.02
(NaBH ₄₎ 4.88 91.25 1.62 0.85 1.4 Production Example 2 100 1.0 0.05 100 0.02
(LiBH ₄₎ 6.00 90.19 1.55 0.99 1.27 Production Example 3 100 1.0 0.05 100 0.02
(MBA) ^a 6.25 89.96 1.20 1.73 0.86

a. M.B.A: methyl boronic acid

Experimental results for each kind of Lewis Acid as a reference NaBH ₄ Was the most reactive and selective.

Table 4 shows the results of the reactant analysis according to the addition amount of Lewis Acid (NaBH ₄ ) as a reference.

Classification Reaction amount (g) GC content (%) 2-NP 5%
Pd / Al ₂ O ₃ EDTA MeOH NaBH ₄ MIPA IPHA Acetone oxime 2-NP IPHA
by-product Production Example 4 100 0.4 0.1 100 0.01 3.44 89.32 2.15 1.98 3.11 Production Example 5 100 0.4 0.1 100 0.02 2.75 90.52 1.91 2 2.82 Production Example 6 100 0.4 0.1 100 0.04 3.13 89.97 1.64 2.23 3.03

Experimental results show that the addition of 0.02% of Lewis Acid (NaBH ₄ ) improves the reactivity and selectivity of the additive.

Example  2: 2- Nitropropane  Hydrogenation of isopropylhydroxylamine ( Isopropylhydroxylamine ) Preparation of compound

To 100 g of 2-nitropropane, 100 g of 2-nitropropane, 0.05 wt% of EDTA catalyst, 1 wt% of 5% Pd / Al ₂ O _{3 and} 0.02 wt% of LiBH ₄ were added to 2-nitropropane, Hydrogenation is carried out at 100 psi. The reaction termination is defined as the reaction termination point when the hydrogen pressure is not reduced. After completion of the reaction, GC analysis revealed that the conversion of 2-nitropropane was 97% or more and the yield of isopropylhydroxylamine was 89% or more.

Example  3: 2- Nitropropane  Hydrogenation of isopropylhydroxylamine ( Isopropylhydroxylamine ) Preparation of compound

2-Nitropropane (100 g) was dissolved in 100 g of a methanol solvent, and 0.05 wt% of EDTA catalyst, 1 wt% of 5% Pd / Al ₂ O _{3 and} 0.02 wt% of methyl boronic acid were added to 2-nitropropane, Hydrogenation is carried out at a pressure of 100 psi. The reaction termination is defined as the reaction termination point when the hydrogen pressure is not reduced. After completion of the reaction, GC analysis revealed that the conversion of 2-nitropropane was 97% or more and the yield of isopropylhydroxylamine was 89% or more.

Example  4: 2- Nitropropane  Hydrogenation of isopropylhydroxylamine ( Isopropylhydroxylamine ) Preparation of compound

100 g of 2-nitropropane was dissolved in 100 g of a methanol solvent, and 0.05 wt% of EDTA catalyst and 1 wt% of 5% Pd / Al ₂ O ₃ were added to 2-nitropropane in a hydrogenation reactor, and hydrogenation was carried out at a reaction temperature of 70 ° C and a hydrogen pressure of 100 psi do. The reaction termination is defined as the reaction termination point when the hydrogen pressure is not reduced. After completion of the reaction, GC analysis revealed that the conversion of 2-nitropropane was 72 to 73%, and the yield of isopropylhydroxylamine was 63 to 64% or more. There is a difference between the conversion rate and the yield rate depending on the respective reaction conditions, and the exact values are shown in [Table 3].

Example  5: 2- Nitropropane  Hydrogenation of isopropylhydroxylamine ( Isopropylhydroxylamine ) Preparation of compound

100 g of 2-nitropropane is dissolved in 100 g of a methanol solvent, and 1% by weight of 5% Pd / Al ₂ O _{3 based} on 2-nitropropane is placed in a hydrogenation reactor and hydrogenation is carried out at a reaction temperature of 70 ° C and a hydrogen pressure of 100 psi. The reaction termination is defined as the reaction termination point when the hydrogen pressure is not reduced. After completion of the reaction, GC analysis revealed that the conversion of the 2-nitropropane reaction was 35-36%, the yield of isopropylhydroxylamine was 35%, and the byproduct monoisopropylamine was 33-34%. There is a difference between the conversion rate and the yield rate depending on the respective reaction conditions, and the exact values are shown in [Table 3].

It was confirmed that in the absence of the deionized EDTA, the hydrogenation reaction results and the reactant mono-isopropylamine were increased and the reactivity and selectivity were affected.

Claims (6)

Palladium catalyst; EDTA; And sodium boron hydride (NaBH _4), lithium-boron hydride (LiBH ₄₎ and methyl Boro Nick Acid (Methyl boronic acid) at least one Lewis acid selected from the group consisting of buchokmae; Nitropropane under hydrogenation conditions to give isopropylhydroxylamine,
Using 0.4-1.5% by weight of the main catalyst of palladium, less than 0.2% by weight of EDTA and 0.01-1% by weight of Lewis acid base as the weight of the reactant of 2-nitropropane,
Wherein the hydrogenation is carried out at a reaction temperature of 70 to 120 ° C and a hydrogen pressure of 100 to 200 psi.
The method of claim 1, wherein the main catalyst is palladium supported on alumina, palladium supported on carbon, or a mixture thereof. delete delete delete delete

Images