KR20120054387A - Method of preparing dialkyl lactamides - Google Patents

Abstract

PURPOSE: A manufacturing method of dialkyl lactamides is provided to improve the yield of dialkyl lactamide by restraining a side reaction which is an oligomerization of lactic acid, lactic acid ester, lactate anion, amine compounds, or combinations thereof. CONSTITUTION: A manufacturing method of dialkyl lactamides comprises: a step of forming ammonium lactate by reacting at least one kinds of a compound selected from a group consisting of lactic acid and esters thereof with an amine compound; and a step of forming dialkyl lactamides by heat-treating the ammonium lactate; and additionally comprises a step of forming the ammonium lactate and/or a step of adding a polymerization inhibitor and/or a polymerization preventer into a reaction mixture in the step for forming dialkyl lactamides.

Description

Method for preparing dialkyl lactamides {Method of preparing dialkyl lactamides}

Disclosed is a method for producing dialkyl lactamides. More specifically, a method for producing dialkyl lactamides, which comprises adding at least one of a polymerization inhibitor and an polymerization inhibitor to a reaction raw material and / or a reaction mixture, is disclosed.

Dialkyl lactamides are materials that can be used as substitutes for dialkylacetamides. Since dialkylacetamides have high solubility in resins, they are widely used in the production of synthetic fibers, films, and fiber coatings. Recently, new markets for LCD cleaners and the demand for apparel due to the global economic recovery The demand is rising rapidly. However, since dialkylacetamides are highly volatile, they have a problem of polluting the environment and harmful to the human body. Since dialkyl lactamides can replace the functions of dialkylacetamides without this problem, the demand is expected to increase rapidly as the semiconductor and LCD industries grow.

One embodiment of the present invention provides a method for producing dialkyl lactamides comprising the step of adding at least one of a polymerization inhibitor and an polymerization inhibitor to the reaction raw material and / or reaction mixture before and / or during the reaction.

According to an aspect of the present invention,

Reacting at least one compound selected from the group consisting of lactic acid and esters thereof with at least one amine compound represented by Formula 1 to form ammonium lactate; And

Heat treating the ammonium lactate to form dialkyl lactamides,

Adding at least one of a polymerization inhibitor and an inhibitor to the reaction mixture of at least one of forming the ammonium lactate and forming the dialkyl lactamides; Provide the manufacturing method:

[Formula 1]

HNR ₁ R ₂

Here, R ₁ and R ₂ are independently substituted or unsubstituted alkyl groups having 1 to 100 carbon atoms.

The ester of lactic acid may comprise at least one compound selected from the group consisting of lactide and monobasic esters of lactic acid.

The monobasic ester of lactic acid may be represented by the following Chemical Formula 2:

[Formula 2]

R ₃ -OC (= O) CH (OH) CH ₃

Wherein R ₃ is substituted or unsubstituted C ₁ ~ C ₁₀ Alkyl group, substituted or unsubstituted C ₁ ~ C ₁₀ Alkoxy group, substituted or unsubstituted C ₆ to C ₂₄ aryl group, substituted or unsubstituted C ₆ to C ₂₄ cycloalkyl group, substituted or unsubstituted C ₆ to C ₂₄ heterocycloalkyl group, or substituted or unsubstituted ah It is a practical skill.

The polymerization inhibitor and the polymerization inhibitor are hydroquinone monomethyl ether, phenothiazine, p-benzoquinone, toluhydroquinone, tert-butyl catechol, hydroquinone, mono-tert-butylhydroquinone, chlor Chloranil, p-nitrosophenyl, 3-mercaptopropyltrimethoxysilane, 3- (methacryloxypropyl) trimethoxysilane and 4-hydroxy-2,2,6,6-tetramethyl- At least one compound selected from the group consisting of 1-piperidinyloxy.

The amount of the amine compound added may be 100 to 1500 mol parts based on 1 mol part of the sum of the lactic acid and esters thereof.

The total amount of the polymerization inhibitor and the polymerization inhibitor may be 0.1 to 10 parts by weight based on 100 parts by weight of the sum of the lactic acid and its esters.

Forming the ammonium lactate may be carried out at a temperature of 50 ~ 70 ℃.

Forming the dialkyl lactamides may be carried out at a temperature of 100 ~ 200 ℃.

According to one embodiment of the present invention, lactic acid, an ester of lactic acid, a lactate anion, an amine compound or a side reaction by adding at least one of a polymerization inhibitor and an polymerization inhibitor to the reaction raw material and / or the reaction mixture before and / or during the reaction There can be provided a method for producing dialkyl lactamides which can suppress the oligomerization reaction of these combinations to improve the yield of dialkyl lactamide.

1 is a graph showing the yield change of the dialkyl lactamide according to the addition amount of hydroquinone as a polymerization inhibitor in the method for producing dialkyl lactamides according to an embodiment of the present invention.

Next, a method for preparing dialkyl lactamides according to one embodiment of the present invention will be described in detail. In the present specification, 'dialkyl lactamides' means dialkyl lactamide and / or derivatives thereof. In the present specification, 'dialkyl lactamides' may be N, N-dialkyl lactamides.

Method for producing dialkyl lactamides according to an embodiment of the present invention is ammonium lactate by reacting at least one compound selected from the group consisting of lactic acid and esters thereof with at least one amine compound represented by the following formula (1) And forming a dialkyl lactamide by heat treating the ammonium lactate:

[Formula 1]

HNR ₁ R ₂

Here, R ₁ and R ₂ are independently substituted or unsubstituted alkyl groups having 1 to 100 carbon atoms.

In the present specification, the term "substituted" means that the hydrogen in the compound is substituted with a halogen group, a hydroxy group, an alkyl group, an alkoxy group, an amine group or a combination thereof.

The method for producing dialkyl lactamides may include adding at least one of a polymerization inhibitor and an polymerization inhibitor to the reaction mixture of at least one of forming the ammonium lactate and forming the dialkyl lactamides. Additionally included. Here, "reaction mixture in the step of forming ammonium lactate" means lactic acid and / or its ester-containing material, and "reaction mixture in the step of forming dialkyl lactamides" means ammonium lactate-containing material. .

Preparation of the dialkyl lactamides by the above method may proceed in the presence of an acetylation catalyst such as M (ClO ₄ ) ₂ .6H ₂ O (M: Mn, Co, Ni, Cu, Zn), and without catalyst. It may proceed.

Forming the ammonium lactate may be carried out at a temperature of 50 ~ 70 ℃. If the temperature is within the above range, if the temperature is within the above range, a high ammonium lactate yield can be obtained without excessive evaporation loss of the amine compound.

Forming the dialkyl lactamides may be carried out at a temperature of 100 ~ 200 ℃. If the temperature is within the above range, the byproduct water can be evaporated smoothly without excessive energy loss due to overheating to obtain a high dialkyl lactamide yield. In the step of forming the dialkyl lactamides, water, which is a byproduct, is produced, and the generated water is immediately converted into water vapor under a high temperature reaction temperature and discharged from the reactor.

The ester of lactic acid may comprise at least one compound selected from the group consisting of lactide and monobasic esters of lactic acid.

The monobasic ester of lactic acid may be represented by the following Chemical Formula 2:

[Formula 2]

R ₃ -OC (= O) CH (OH) CH ₃

Wherein R ₃ is substituted or unsubstituted C ₁ ~ C ₁₀ Alkyl group, substituted or unsubstituted C ₁ ~ C ₁₀ Alkoxy group, substituted or unsubstituted C ₆ to C ₂₄ aryl group, substituted or unsubstituted C ₆ to C ₂₄ cycloalkyl group, substituted or unsubstituted C ₆ to C ₂₄ heterocycloalkyl group, or substituted or unsubstituted ah It is a practical skill.

The monobasic ester of lactic acid may be, for example, ethyl lactate.

The amine compound may be dimethylamine, in which case N, N-dimethyllactamide may be prepared.

The amount of the amine compound added may be 100 to 1500 mol parts based on 1 mol part of the sum of the lactic acid and esters thereof. If the amount of the amine compound added is within the above range, a high ammonium lactate yield can be obtained without excessive consumption of the amine compound. Such amine compounds can be injected in a gaseous state, for example, into reactors filled with lactic acid and / or esters thereof, and optionally polymerization inhibitors and / or polymerization inhibitors. In this case, the polymerization inhibitor and / or the polymerization inhibitor may be injected into the reactor in a state dissolved in lactic acid and / or ester thereof. The reactor can be, for example, a batch reactor. The gaseous amine compound is continuously injected into the reactor and contacted with the reaction mixture for a predetermined time, and then continuously discharged out of the reactor.

The polymerization inhibitor or polymerization inhibitor inhibits or prevents the lactic acid, the ester of lactic acid, the lactate anion and / or the amine compound from reacting with each other or two or more kinds with each other to form an oligomer. Thereby, the yield of the dialkyl lactamides represented by following formula (1) increases.

[Equation 1]

Yield (%) of dialkyl lactamide = (moles of produced dialkyllactamide) / (moles of injected lactic acid and its esters) × 100

The polymerization inhibitor and the polymerization inhibitor are hydroquinone monomethyl ether, phenothiazine, p-benzoquinone, toluhydroquinone, tert-butyl catechol, hydroquinone, mono-tert-butylhydroquinone, chlor Chloranil, p-nitrosophenyl, 3-mercaptopropyltrimethoxysilane, 3- (methacryloxypropyl) trimethoxysilane and 4-hydroxy-2,2,6,6-tetramethyl- At least one compound selected from the group consisting of 1-piperidinyloxy.

The total amount of the polymerization inhibitor and the polymerization inhibitor may be 0.1 to 10 parts by weight based on 100 parts by weight of the sum of the lactic acid and its esters. When the total addition amount of the polymerization inhibitor and the polymerization inhibitor is within the above range, a high dialkyl lactamide yield can be obtained without excessive consumption of the polymerization inhibitor and the polymerization inhibitor.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these embodiments.

Examples 1-4

(Production of Dimethyllactamide from Lactic Acid and Dimethylamine)

First, a predetermined amount of hydroquinone was added to 83.3 g of lactic acid (85 wt%) as shown in Table 1 to completely dissolve it. Thereafter, the mixed solution was placed in a 150 ml batch reactor equipped with a gas inlet tube, a gas outlet tube, and a sampling port, and the gaseous dimethylamine was continuously introduced into the mixed solution through the gas inlet tube at a rate of 250 ml / min. The reaction proceeded while flowing. At this time, the temperature of the reactor was maintained at 60 ° C for 90 minutes, and then heated again to 170 ° C and maintained at this temperature for 170 minutes. In addition, the unreacted dimethylamine was discharged to the outside of the reactor through the gas outlet pipe.

Example 1 Example 2 Example 3 Example 4 Hydroquinone
Addition amount (g) 0.5 1.0 1.5 2.0

Comparative Example 1

Dimethyl lactamide was prepared in the same manner as in Examples 1 to 4 except that no hydroquinone was used.

Evaluation example

In Examples 1 to 4 and Comparative Example 1, after the temperature of the reactor reached 170 ℃ sample is taken from the reactor at 10 minutes intervals, and then the components and components of each sample using gas chromatography The content ratio of the components was analyzed. After calculating the yield of dimethyl lactamide according to Equation 1 using the data after the steady state of the analysis data, the results are shown in Table 2 and FIG. In Examples 1-4 and Comparative Example 1, the yield of dimethyl lactamide reached a steady state when about 130 minutes had elapsed after the start of the reaction at 170 ° C.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Yield of dimethyl lactamide (%) 58.6 62.9 66.9 58.8 51.7

Referring to Table 2, the yield of dimethyl lactamide was found that Examples 1 to 4 are higher than Comparative Example 1.

Referring to FIG. 1, the yield of dimethyl lactamide does not always increase as the amount of hydroquinone is increased, but the optimal amount of hydroquinone is present to maximize the yield of dimethyl lactamide.

Although the preferred embodiment according to the present invention has been described above with reference to the embodiment, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible therefrom. Could be. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (8)

Reacting at least one compound selected from the group consisting of lactic acid and esters thereof with at least one amine compound represented by Formula 1 to form ammonium lactate; And
Heat treating the ammonium lactate to form dialkyl lactamides,
Adding at least one of a polymerization inhibitor and an inhibitor to the reaction mixture of at least one of forming the ammonium lactate and forming the dialkyl lactamides; Manufacturing Method:
[Formula 1]
HNR ₁ R ₂
Here, R ₁ and R ₂ are independently substituted or unsubstituted alkyl groups having 1 to 100 carbon atoms. The method of claim 1,
The ester of lactic acid is a method for producing dialkyl lactamides comprising at least one compound selected from the group consisting of lactide and monobasic ester of lactic acid. The method of claim 2,
The monobasic ester of lactic acid is a method for producing dialkyl lactamides represented by the following general formula (2):
(2)
R ₃ -OC (= O) CH (OH) CH ₃
Wherein R ₃ is substituted or unsubstituted C ₁ ~ C ₁₀ Alkyl group, substituted or unsubstituted C ₁ ~ C ₁₀ Alkoxy group, substituted or unsubstituted C ₆ to C ₂₄ aryl group, substituted or unsubstituted C ₆ to C ₂₄ cycloalkyl group, substituted or unsubstituted C ₆ to C ₂₄ heterocycloalkyl group, or substituted or unsubstituted ah It is a practical skill. The method of claim 1,
The polymerization inhibitor and the polymerization inhibitor are hydroquinone monomethyl ether, phenothiazine, p-benzoquinone, toluhydroquinone, tertiary butyl catechol, hydroquinone, mono-tert-butylhydroquinone, chlor Chloranil, p-nitrosophenyl, 3-mercaptopropyltrimethoxysilane, 3- (methacryloxypropyl) trimethoxysilane and 4-hydroxy-2,2,6,6-tetramethyl- A method for producing dialkyl lactamides comprising at least one compound selected from the group consisting of 1-piperidinyloxy. The method of claim 1,
The addition amount of the said amine compound is the manufacturing method of dialkyl lactamides which is 100-1500 mol part with respect to 1 mol part of sum total of the said lactic acid and its ester. The method of claim 1,
The total addition amount of the said polymerization inhibitor and the polymerization inhibitor is 0.1-10 weight part with respect to 100 weight part of total sum of the said lactic acid and its ester. The method of claim 1,
Forming the ammonium lactate is a method for producing dialkyl lactamides proceeds at a temperature of 50 ~ 70 ℃. The method of claim 1,
Forming the dialkyl lactamides is a method for producing a dialkyl lactamide proceeds at a temperature of 100 ~ 200 ℃.

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