JPH0473422B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to tertiary (hereinafter abbreviated as t-)alkylamine (hereinafter abbreviated as RNH2)
For more details on the method for producing lactic acid and
-t-alkyl lactamide (hereinafter referred to as t-ALA
The present invention relates to a method for simultaneously producing t-RNH2 and lactic acid by hydrolyzing t-RNH2 and lactic acid in the presence of an alkali and water.

t-RNH2 has many applications as an intermediate raw material for various compounds, including rubber drugs, monomers for modifying polymer compounds, pharmaceuticals, agricultural chemicals, surfactants,
It is important as a raw material for antistatic agents, etc.

In addition, lactic acid is used in a wide range of fields such as brewing, beverages, leather, textile finishing, dyeing mordants, pharmaceuticals, and pharmaceuticals.

BACKGROUND TECHNIQUES General industrial methods for producing amines include (a) a method in which alcohols and ammonia are reacted in the presence of a dehydration catalyst; (b) A method of reacting alcohols with ammonia in the presence of a hydrogenation catalyst and hydrogen. (c) A method of reacting aldehydes or ketones with ammonia in the presence of a hydrogenation catalyst and hydrogen. However, each method yields a mixture of two or more amines and is not suitable as a single method for producing t-RNH2.

As a method for synthesizing t-RNH2, for example, t-
Regarding butylamine (hereinafter abbreviated as t-BA), (d) Hoffman decomposition of trimethylacetamide. (e) Hydrogenation of 2,2-dimethylethyleneimine (ORGANIC SYNTHESES COLLECTIVE,
VOL.3, 148) (f) Hydrolysis of t-butyl urea (ORG.SYN.COLLECTIVE, VOL.3, 154) has been reported, but these methods are difficult to industrialize due to raw material availability. There is.

Recently, a method for obtaining t-BA and the corresponding organic acid by alkaline hydrolysis of the organic acid N-t-butylamide has been reported.

(1) N-t-butylformamide (J.Am.Chem.
Soc., VOL.70, 4048, 1948) (2) N-t-butyl (meth)acrylamide (Special Publication No. 54-881) (3) N,N'-di-t-butyl-3,3'- Thiodipropionic acid amide (JP-A-50-95210) and the like.

On the other hand, as an industrial method for producing lactic acid, in addition to the fermentation method, lactonitrile (hereinafter abbreviated as LCN) is produced by an addition reaction of acetaldehyde and hydrogen cyanide as a chemical synthesis method.
A method has been implemented in which the obtained LCN is hydrolyzed in the presence of an acid.

Problems to be Solved by the Present Invention In order to industrialize the method of co-producing t-RNH2 and organic acids by hydrolyzing N-t-alkylamides of organic acids, it is difficult to handle the co-produced organic products. It is desirable that it is stable and has high utility value, and that the amount of demand corresponds to t.
-It is necessary that the amount of production is higher than that of RNH2.
Otherwise, the co-produced organic products will become surplus and cause inconvenience.

The problem with the above-mentioned method of co-producing t-BA and organic acids is that in method (1), the by-product formic acid does not have high utility value, so it is not economical to recover it from the aqueous solution. It's not a good idea.

In method (2), since the co-produced (meth)acrylic acid has a property of being easily polymerized, it is easily polymerized during hydrolysis or purification treatment, and a good yield of (meth)acrylic acid cannot be expected.

In method (3), toxic and corrosive hydrogen sulfide may be generated during the hydrolysis process.

As mentioned above, each has its own problems.

From this perspective, the present inventors have developed various N-RNH2 production methods using organic acid co-production methods.
We investigated t-alkyl organic acid amides and found that a method of hydrolyzing t-ALA with an alkaline aqueous solution to co-produce t-RNH2 and lactic acid is an excellent method for solving the above problems. This discovery led to the completion of the present invention.

Means for Solving the Problems The method of the present invention provides N-
A method for producing a t-alkylamine represented by the general formula (), which comprises simultaneously producing lactic acid by hydrolyzing t-alkyl lactamide with an aqueous alkaline solution at a temperature of 130 to 220°C. .

CH ₃ -CH(OH)-CONHR () R-NH ₂ () (R: t-alkyl group having 4 to 22 carbon atoms) As mentioned above, lactic acid is used in a wide range of fields, has high utility value, and is in high demand. Since the amount is large, t-RNH2
The amount of production is not constrained by this.
Furthermore, unlike unsaturated carboxylic acids such as (meth)acrylic acid, lactic acid does not polymerize during reactions or purification processes and is stable. Furthermore, unlike the case of thiodipropionic acid amide, no toxic or corrosive substances are produced in the hydrolysis of t-ALA. Lactic acid is very convenient as an organic acid to be co-produced in this way.

Furthermore, as a necessary requirement for industrialization of the method of the present invention, it is important that raw materials for producing t-ALA are easily available, and the method of the present invention is also excellent in this respect.

To produce the raw material t-ALA used in the method of the present invention, LCN produced on an industrial scale as described above can be used. Moreover, the reaction product obtained by reacting acetaldehyde and hydrogen cyanide (usually an aqueous solution containing 75 to 80% LCN) can be used as it is without purification.

That is, t-ALA can be obtained by reacting a corresponding t-alkyl alcohol (hereinafter abbreviated as t-ROH) or olefin with LCN.

Reaction conditions are concentration 40-95%, preferably 55-85%
% sulfuric acid aqueous solution as the reaction medium, temperature 0~80℃,
Preferably, LCN and t-ROH or olefin are reacted at 30 to 60°C. The molar ratio of LCN and t-ROH or olefin is 1:0.9 to 1.2; the amount of sulfuric acid used is 0.9 to 2.0 times the mole of LCN. The reaction time varies depending on the reaction conditions and the type of t-ROH or olefin used, but is 1 to 10 hours.

The reaction procedure is to charge an aqueous sulfuric acid solution into a reaction vessel and add LCN and t-ROH or olefin, or vice versa.
Alternatively, a method of adding an aqueous sulfuric acid solution to the mixture with olefin is preferable from the viewpoint of removing the reaction heat generated and suppressing the formation of impurities due to side reactions.

After the reaction is complete, add an alkali metal hydroxide such as sodium hydroxide, potassium hydroxide, or ammonium to the reaction solution to neutralize it to a neutral range, or
Alternatively, water is added to dilute the sulfuric acid concentration to 5-30%, and liberated t-ALA is separated by a conventional method.

Next, hydrolysis of t-ALA is carried out in a closed pressure-resistant reaction vessel by adding an alkaline aqueous solution to t-ALA.

The reaction conditions are a temperature of 130-220°C, preferably 150°C.
~190°C, and the alkali used is a hydroxide of an alkali metal such as Na, K, or Li or an alkaline earth metal such as Ca or Ba. The concentration of the alkaline aqueous solution used is 3 to 50% by weight, preferably 7 to 45% by weight. Since alkali is consumed as lactic acid is produced by hydrolysis, the amount of alkali used should be at least equimolar to the raw material t-ALA, usually 1.0 to 1.5 times the mole, preferably 1.05
~1.30 times the molar amount.

The pressure inside the reaction vessel increases as the hydrolysis reaction progresses, and the reaction is allowed to continue under pressure for 3 to 15 hours.

As a method for separating the produced t-RNH2 from the reaction product liquid, there is a method of distilling the product liquid after the reaction is completed. However, more preferably, once the hydrolysis reaction has progressed and reached an appropriate pressure (7 to 15 Kg/cm ² ), the generated amine can be released into the system by utilizing the energy of the gas phase inside the container while the hydrolysis reaction is progressing. It is best to let it drain out in small amounts.

At this time, the pressure inside the reaction vessel was 3Kg/cm ² (abs.)
It is necessary to hold it more than that. If the system is operated under low pressure, a large amount of water in the container will be distilled out, and the alkali concentration in the system will increase, side reactions will occur, and impurities will increase.

In the step of separating t-RNH2, it is desirable to separate the produced amine from the product liquid as much as possible. In the next lactic acid recovery step, acid is added to make the product solution acidic, so the amine remaining in the product solution becomes an acid salt and is fixed, resulting in a decrease in the amine recovery rate. Furthermore, the amount of acid required to be added increases, which is not a good idea. By increasing the amine distillation rate in the t-RNH2 separation step, the resulting t-RNH2
Since RNH2 is accompanied by water, it is usually an aqueous solution with a concentration of 40 to 80% by weight, but highly pure t-RNH2 can be easily obtained by distillation.

In the product liquid from which t-RNH2 is separated, lactic acid exists in the form of an alkali salt such as sodium lactate. Add inorganic acids such as sulfuric acid and hydrochloric acid to the generated liquid to adjust the pH.
2.5-4.0 to obtain free lactic acid. The obtained lactic acid is purified by acid precipitation or esterification treatment, if necessary.

The method of the present invention _uses t _- BA, t _{- octylamine ,} or t _{- RNH2} consisting of _C12H25NH2 to _{C14H29NH2 ,} or _C18H37NH2 to _C22H45NH2 .
It can be used for the production of t-RNH2 such as.

Examples The method of the present invention will be explained below by reference examples and examples, but the present invention is not limited only to these examples.

Reference example 1 [Nt-butyl lactamide (hereinafter referred to as t-
Synthesis of 74.5% (abbreviated as BLA)] In a 1 liter four-necked flask equipped with a stirrer, condenser, thermometer, and dropping funnel, 74.5% (hereinafter referred to as
(Based on weight) Sulfuric acid: Charge 260.1g and bring the temperature to 30℃.

This is combined with 90.9 g of LCN aqueous solution with a concentration of 78.7% and t-
Butyl alcohol: A mixture with 74.0 g was added dropwise over 1 hour. During this time, the reaction system is cooled to maintain the reaction temperature at 30°C.

In order to complete the reaction, the temperature was further increased to 30℃ after the completion of the dropwise addition.
The mixture was aged for 1 hour at 50°C and for 4 hours at 50°C.

After the reaction was completed, about 300 ml of 28% aqueous ammonia was added to the reaction product solution to adjust the pH to 7.5. The liquid separates into two phases. The upper layer is a phase consisting of t-BLA. The layers were separated to separate a phase consisting of t-BLA. In addition, if the temperature is maintained at 60℃ during this neutralization/separation operation, t
- BLA remains liquid, making it easy to process.

Amount of obtained t-BLAB: 138.9g; Purity:
The yield (in terms of purity) was 91.6%.

Example 1 t-BLA obtained by the method of Reference Example 1: 892 g was placed in a stainless steel pressure-resistant reaction vessel equipped with a stirrer, a thermometer, a pressure gauge, and a distillation tube (with a control valve).
(Purity: 781g), Sodium hydroxide: 250g, Water:
Prepare 1000g and heat to 170℃.

Approximately 30 minutes after raising the temperature to 170℃, the internal pressure will be 7 to 10Kg/cm ²
(abs.) rose. After that, increase the liquid temperature to 170-173℃.
t-BA was distilled out while maintaining the internal pressure at 7 Kg/cm ² (abs.). At this time, some of the water is entrained and distilled out. After about 4 hours, the pressure will decrease to 7.
The distillation operation of t-BA was continued until the pressure decreased to 3 Kg/cm ² , but the pressure decreased below 3 Kg/cm ² .

The amount of distilled t-BA aqueous solution was 662 g;
The BA concentration was 61.9% (by gas chromatography analysis). t-BA yield (pure): 410
g; Yield: 92.8%.

The obtained t-BA aqueous solution was subjected to rectification treatment using a distillation apparatus (Oldasho, 10 stages) to obtain 404 g of t-BA as a fraction having a top temperature of 43.5°C. Purity: 98.5%; distillation yield (purity conversion): 97.0%.

After separating t-BA, concentrated sulfuric acid was added to the resulting solution to adjust the pH to 3.5 to obtain free lactic acid. Lactic acid content: 516
Yield (according to carboxylic acid analyzer): 95%.

Effects of the present invention By the method of the present invention, t-RNH2 and lactic acid, which were conventionally produced separately by separate production routes, can be produced simultaneously with ease and in good yield.

In other words, in the conventional method, (a) lactic acid is produced through the following steps: (a-1) producing LCN by an addition reaction between acetaldehyde and hydrogen cyanide; and (a-2) hydrolyzing LCN. , and (b) t-RNH2; (b-1) producing t-alkylformamide by reaction of t-ROH or the corresponding olefin with hydrogen cyanide; (b-2) the obtained t-RNH2; It is manufactured separately through a process of hydrolyzing alkylformamide.

In contrast, according to the method of the present invention, LCN
By hydrolyzing t-ALA produced using t-ALA as a raw material, both products can be produced in good yields with fewer steps than conventional methods.

The method of the present invention is extremely advantageous as an industrial method for producing t-RNH2 and lactic acid.

Claims (1)

[Claims] 1. Lactic acid is simultaneously produced by hydrolyzing an N-tertiary alkyl lactamide represented by the general formula () with an alkaline aqueous solution at a temperature of 130 to 220°C. General formula ()
A method for producing a tertiary alkylamine represented by CH ₃ -CH(OH)-CONHR () R-NH ₂ () (R: tertiary alkyl group having 4 to 22 carbon atoms)