JP2608724B2 - Method for producing benzotriazoles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing benzotriazoles, and more particularly to a novel method for producing benzotriazoles for reducing hydroxybenzotriazoles. Benzotriazoles are very useful substances as rust preventives and corrosion inhibitors, synthetic resin stabilizers and the like.

(Prior art) Such benzotriazoles are currently industrially manufactured by the following formula.

On the other hand, the known techniques from the same starting hydroxybenzotriazoles of the present invention include (a) a method of reducing hydroxybenzotriazoles with hydrogen in the presence of a catalyst [CA 73 66585h (1970), Ger.
fen 2003828 Jul 30 1970] (b) Hydroxybenzotriazoles as reducing agents PX
₃ (X = Cl, Br, OEt, OPh) method [CA 73 77250
w (1970), Ger Offen 2003 860 Aug 6 1970] (c) A method of reacting hydroxybenzotriazoles with α-halogenated malonic acid ethyl ester in the presence of an alkali (JP-A-52-83467). A method in which benzotriazole is reduced with hydrogen iodide in a sealed tube to make benzotriazole polyiodid (Ann 311 333 (1900) Zinke
Etc.).

These known methods have drawbacks such as high raw material cost and toxicity, or have drawbacks such as an increase in the size of a reactor for hydrogen reduction, and are disadvantageous industrially and economically. Furthermore, all of these known methods have severe reaction conditions and many side reactions such as amine-based coloring matter, so that purification is difficult.

The present inventors have already filed patent applications for a method for solving the drawbacks of the above-described conventional methods (Japanese Patent Publication Nos.
1-55507).

In these methods, hydroxybenzotriazoles or salts thereof are at least one selected from the group consisting of iron, cobalt, tin and aluminum metals, or at least one selected from the group consisting of ferrous salts and stannous salts. 1
A method for producing benzotriazoles, characterized in that the reaction is carried out in a kind of acidic medium. The features of these methods are that there are few by-products of amine-based coloring substances, high reaction yield (based on hydroxybenzotriazole), mild reaction conditions are required, and low-cost raw materials that are industrially easily available can be used. And the use of highly toxic substances such as nitrous acid.

(Problems to be Solved by the Invention) An object of the present invention is to provide the above-mentioned JP-B-61-30672 and JP-B-61-5.
Another object of the present invention is to provide a method for producing benzotriazoles, which further improves the method described in 5507 and uses less metal and acidic medium.

(Means for Solving the Problems) The present invention has a general formula [Wherein R ₁ , R ₂ , R ₃ and R ₄ represent the same or different atoms or groups selected from a hydrogen atom, a halogen atom, and a group stable in the reaction medium in the reaction medium], represented by the formula: Or a salt thereof is reacted with lead in an acidic medium or with a catalytic amount of lead or a lead compound in the presence of a metal having a greater ionization tendency than lead. [Wherein R ₁ , R ₂ , R ₃ and R ₄ are as defined above].

The features of the present invention include: (1) a high purity product close to white with few by-products of an amine-based coloring substance can be easily obtained, and a complicated purification step can be omitted; (2) a high reaction yield ( (Based on hydroxybenzotriazole) (3) Use of small amounts of metal and acidic medium is required (4) Mild reaction conditions are required (5) Inexpensive raw materials that are easily available industrially can be used (6) Nitrite and the like (7) In particular, good results can be obtained when a combination of a catalytic amount of lead and an appropriate amount of aluminum is used.

The general formula (I) used as a starting material of the present invention
Substituents of hydroxybenzotriazoles represented by
R ₁ , R ₂ , R ₃ and R ₄ represent the same or different atoms or groups selected from a hydrogen atom, a halogen atom, and a group which is stable in a reaction medium. Specific examples of groups that are stable in the reaction in this reaction catalyst include an alkyl group, a halogenated alkyl group, an allyl group, an alkoxy group, a carboxy group, an amino group, an acyl group, a sulfamino group, a carbamoyl group, a sulfamoyl group, and a sulfone group. Can be mentioned. The salts of hydroxybenzotriazoles used in the present invention are salts or complexes capable of releasing hydroxybensotriazoles in an acidic medium in a reaction system, and specifically include alkali metal salts and alkaline earth metal salts. , Ammonium salts, hydrazinium salts, and salts or complexes of iron, cobalt, tin, aluminum, zinc, titanium, copper and the like.

Specific examples of hydroxybenzotriazoles include:
1-hydroxybenzotriazole, 5-chloro-1-
Hydroxybenzotriazole, 4,5-dichloro-1-
Hydroxybenzotriazole, 4,5,6,7-tetrachloro-1-hydroxybenzotriazole, 6-bromo-
1-hydroxybenzotriazole, 5-methyl-hydroxybenzotriazole, 6-trifluoromethyl-1-hydroxybenzotriazole, 1-hydroxybenzotriazole-6-sulfonic acid, 6-amino-1
-Hydroxybenzotriazole, 5-methoxy-1-
Examples thereof include hydroxybenzotriazole, 5-acetyl-1-hydroxybenzotriazole, 1-hydroxybenzotriazole-5-carboxylic acid, and the like.
These raw materials may be used as they are without removing the solvent from the raw material synthesis solution, or may be isolated.

Metal lead used in the present invention is not particularly limited in shape,
A wide range of forms of metallic lead, such as powder, plate, lump or needle, can be used, but powdered metallic lead is advantageously used to complete the reaction at a lower temperature and in a shorter time. The amount of the metal lead to be used is about 0.5 to 10 times, preferably about 1.0 to 4.0 times, the mole atom of the hydroxybenzotriazole of the formula (I).

In the present invention, by allowing a metal having a higher ionization tendency than lead to coexist in the reaction system, the redox of the metal lead can be performed, and the amount of the metal salt used can be reduced to about the catalyst amount. Aluminum, iron, nickel, tin, cobalt, and magnesium are used as metals having a higher ionization tendency than lead. These metals can be used alone or in combination of two or more. There is no particular limitation on the shape of these metals to be used, and a wide range of forms such as powdery plate, foil, lump, and needle are used, but powdered metal is used to complete the reaction at a lower temperature and in a shorter time. Is advantageously used. The amount of the metal having a higher ionization tendency than lead is about 0.5 to 10 times the molar atom of the hydroxybenzotriazoles of the general formula (I), preferably about 1.0 to 10 times.
2.0 times the molar atom. In this case, the amount of lead used is about 0.00001 to 0.5 times mol, preferably about 0.0001 to 0.1 times mol of hydroxybenzotriazole.

In the present invention, when a metal having a higher ionization tendency than lead is used in combination, a lead compound can be used instead of metal lead.

The lead compound may have any valence of zero, divalent or tetravalent lead, and these compounds may be used in the form of a hydrate. As the lead compound to be used, conventionally known compounds can be widely used. For example, lead fluoride, lead chloride, lead bromide,
Lead halides such as lead iodide, lead nitrate, lead sulfate, lead perchlorate, lead borate, lead carbonate, inorganic lead such as lead phosphate, lead acetate,
Examples include lead fatty acid such as lead oxalate and lead stearate, lead oxide, lead hydroxide, and a complex of lead having zero valence, two valences, and four valences. Examples of the ligand of the complex include chelating agents such as ethylenediaminetetraacetic acid and nitrilotriacetic acid, carboxyl compounds, carbonyl compounds such as carboxylic acids, amines, oximes, ammonia, nitrogen compounds such as nitriles, and phosphorus compounds such as organic phosphines. Can be These lead compounds can be used alone or in combination of two or more. The amount of the lead compound used is about 0.00001 to 0.5 with respect to the hydroxybenzotriazoles of the general formula (I).
A molar amount, preferably about 0.0001 to 0.1 times, is used.

The acidic medium used in the present invention is a mineral acid, an acid salt of a mineral acid,
It is at least one selected from the group consisting of organic carboxylic acids, organic sulfonic acids and acid anhydrides thereof. Specifically, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acidic ammonium sulfate, acidic sodium sulfate, formic acid, acetic acid, chloroacetic acid, toluenesulfonic acid, chlorosulfonic acid, sulfuric anhydride, fuming sulfuric acid, iron chloride, tin chloride, aluminum chloride, Ammonium chloride and the like can be mentioned. Particularly, industrially preferably, hydrochloric acid or sulfuric acid is used directly or diluted with water.

The amount of the acidic medium to be used is usually about 0.1 to 5.0 times, preferably about 0.5 to 2.0 times mol, of the hydroxybenzotriazoles, because the hydroxybenzotraazoles themselves are weakly acidic. . The method of using the acidic medium is not particularly limited, but an amount that adjusts the acidity of the reaction system to pH 4 or less to obtain an appropriate reaction rate is used. If lead or a metal with a higher ionization tendency than lead and lead is present in the reaction system, supply the acidic medium required for the reaction to the reaction system at once, rather than supply it to the reaction system in a divided or continuous manner. Better. When an acidic medium required for the reaction is present in the reaction system at once, it is better to supply lead or a lead compound and a metal having a higher ionization tendency than lead in accordance with the reaction.

As the reaction solvent, at least one homogeneous or heterogeneous solvent selected from the group consisting of the above-described acidic medium, water, alcohols, esters, hydrocarbons, acid amides, and halogenated hydrocarbons can be used. Usually, reaction solvents of water, formic acid, acetic acid, and alcohols are often used. The amount of the reaction solvent used is an amount capable of mixing and stirring because the present invention is a heterogeneous reaction using a metal. The reaction temperature can be carried out at 0 to 160 ° C, preferably 20 to 120 ° C.
° C. The reaction pressure varies greatly depending on the reaction solvent and the reaction temperature, and is not particularly limited. Generally, a reduced pressure of 0.5 kg / cm ² to a pressure of 10 kg / cm ² is used. Usually, atmospheric pressure is used.
When an inert gas such as a nitrogen gas or an argon gas is injected under pressure in order to prevent a gas phase explosion in the reaction system, the reaction can be performed at an arbitrary high pressure, for example, 10 to 100 kg / cm ² .
The reaction time varies depending on conditions such as temperature, but is usually about 0.1 to 10
Time is preferred.

The reaction of the present invention is a heterogeneous reaction using a metal as a reducing agent. In order to increase the efficiency of the reaction, stirring is preferably performed. The reaction can be carried out by either a continuous method or a batch method.

From the reaction solution containing benzotriazoles obtained by the method of the present invention, the target product can be easily separated by ordinary operations such as distillation, concentration, extraction, and recrystallization. It can be used as it is for rust preventives and the like, and if necessary, used after purification by distillation, recrystallization and the like.

(Examples) Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these embodiments.

Example 1 In a 100 ml four-necked flask having a thermometer, a stirrer, a nitrogen gas inlet tube and a reflux condenser, 1.00 g (7.4 mmol) of 1-hydroxybenzotriazole and 16.6 g (80.1 g) of lead powder were placed.
Mmol) and 40 ml of water and heated to 100 ° C. with stirring. To this reaction solution, 15.0 g (148 mmol) of concentrated hydrochloric acid was added dropwise over 2 hours, and the reaction was further continued for 5 hours.

The reaction solution was extracted twice with 40 ml of n-amyl alcohol, and the extract was analyzed by high performance liquid chromatography (HPLC) (Shimadzu Corporation, Model LC-3). As a result, 0.87 g (7.3 mmol) of benzotriazole was obtained. This corresponds to a yield of 99%. In addition, 1-hydroxybenzotriazole was not detected. The benzotriazole isolated from this extract was completely identical in both NMR and IR with a separately prepared benzotriazole sample.

Example 2 To the same apparatus as in Example 1, 4.00 g (29.6 mmol) of 1-hydroxybenzotriazole, 0.12 g (0.58 mmol) of lead powder, 0.96 g (35.5 mmol) of aluminum powder (100 mesh) and 40 ml of water were added. Heat to 100 ° C. with stirring. 1.81 g (17.8 mmol) of concentrated hydrochloric acid was added dropwise to the reaction solution over 2 hours, and the reaction was further continued for 5 hours. As a result, the yield of benzotriazole was 99%. Unreacted 1-hydroxybenzotriazole was not detected.

Comparative Example 1 The reaction was carried out under the same conditions as in Example 2 except that lead was not used. HPLC analysis showed that the yield of benzotriazole was 64.
%, And unreacted 1-hydroxybenzotriazole is
36%.

Comparative Example 2 1.98 g of iron powder in Example 2 instead of lead and aluminum
(35.5 mmol) alone. HP
As a result of LC analysis, the yield of benzotriazole was 30%, and unreacted 1-hydroxybenzotriazole was 70%.

Example 3 In the same apparatus as in Example 1, 4.00 g (29.6 mmol) of 1-hydroxybenzotriazole, 40 ml of water, and 0.12 g of lead powder (0.
58 mmol) and 4.22 g (35.5 mmol) of tin powder,
Heat to 100 ° C. with stirring. To this reaction solution, add concentrated hydrochloric acid 1.8
1 g (17.8 mmol) was added dropwise over 2 hours, and the mixture was further reacted for 5 hours.

As a result, the yield of benzotriazole is 25%,
Unreacted 1-hydroxybenzotriazole was 75%.

Comparative Example 3 The reaction was carried out under the same conditions as in Example 3 except that no lead powder was used. As a result of HPLC analysis, the yield of benzotriazole was 17%, and unreacted 1-hydroxybenzotriazole was 83%.

Example 4 Using the same equipment as in Example 1, 4.00 g (29.6 mmol) of 1-hydroxybenzotriazole, 0.82 of lead chloride
(2.9 mmol), aluminum powder (100 mesh) 0.96
g (35.5 mmol) and 40 ml of water were added and heated to 100 ° C. with stirring. 1.81 g (17.8 mmol) of concentrated hydrochloric acid was added to this reaction solution.
Was added dropwise over 2 hours, followed by a further reaction for 5 hours.
As a result, benzotriazole was 96% and unreacted 1
-Hydroxybenzotriazole was 3%.

Example 5 4.00 g (29.6 mmol) of 1-hydroxybenzotriazole, 0.12 g (0.58 mmol) of lead powder, 0.96 g (35.5 mmol) of aluminum powder (100 mesh) and 40 ml of methanol were added to the same apparatus as in Example 1. Heat to 65 ° C. with stirring. 1.81 g (17.8 mmol) of concentrated hydrochloric acid was added dropwise to the reaction solution over 2 hours, and the reaction was further continued for 5 hours.
As a result, the yield of benzotriazole was 74%, and unreacted 1-hydroxybenzotriazole was 25%.

Example 6 To the same apparatus as in Example 1, 4.00 g (29.6 mmol) of 1-hydroxybenzotriazole, 0.12 g (0.58 mmol) of lead powder, 0.96 g (35.5 mmol) of aluminum powder (100 mesh) and 40 ml of heptane were added. Heat to 98 ° C. with stirring. 1.81 g (17.8 mmol) of concentrated hydrochloric acid was added to the reaction mixture.
The mixture was added dropwise over a period of time, and the reaction was further performed for 8 hours. As a result, the yield of benzotriazole was 90%, and unreacted 1-hydroxybenzotriazole was 10%.

Example 7 Using the same apparatus as in Example 1, 1 g (7.4 mmol) of 1-hydroxybenzotriazole, 0.12 g (0.58 mmol) of lead powder, 0.96 g (35.5 mm) of aluminum powder (100 mesh) were used.
Mmol) and 40 g (666.7 mmol) of acetic acid, and the mixture was heated to 100 ° C. with stirring and reacted for 7 hours. as a result,
Benzotriazole yield was 70% and unreacted 1-hydroxybenzotriazole was 30%.

Example 8 Using the same apparatus as in Example 1, 4 g (29.6 mmol) of 1-hydroxybenzotriazole and 0.12 g (0.58 g) of lead powder were used.
Mmol), aluminum powder (100 mesh) 0.96 g (3
5.5 mmol) and 40 ml of water, and heated to 100 ° C. with stirring. To this reaction solution, 7.0 g (35.6 mmol) of 50% sulfuric acid was added over 2 hours, and the reaction was further continued for 5 hours. As a result, the yield of benzotriazole was 95%, and unreacted 1-hydroxybenzotriazole was 5%.

Example 9 Using the same apparatus as in Example 1, 1 g of 1-hydroxybenzotriazole (29.6 mmol) and 0.12 g of lead powder (0.58 g) were used.
Mmol), aluminum powder (100 mesh) 0.96 g (3
5.5 mmol) and 40 ml of water, and heated to 100 ° C. with stirring. 13.0 g (17.8 mmol) of 5% hydrochloric acid was added to this reaction solution.
Was added over 2 hours, and the reaction was continued for another 5 hours.
As a result, the yield of benzotriazole was 98%, and unreacted 1-hydroxybenzotriazole was 1%.

Example 10 Using the same apparatus as in Example 1, 1 g of 1-hydroxybenzotriazole (29.6 mmol) and 0.12 g of lead powder (0.58 g) were used.
Mmol) and 40 ml of water and heated to 100 ° C. with stirring. 1.81 g (17.8 mmol) of concentrated hydrochloric acid and 0.96 g (35.5 mmol) of aluminum powder (100 mesh) were added to this reaction solution.
Was added over 2 hours, and the reaction was continued for another 5 hours.
As a result, the yield of benzotriazole was 99%, and unreacted 1-hydroxybenzotriazole was not detected.

Example 11 Example 2 was repeated except that the reaction temperature was 60 ° C. and the reaction time was 48 hours.
The reaction was carried out under the same conditions as described above. As a result of HPLC analysis, the yield of benzotriazole was 92% and unreacted 1-hydroxybenzotriazole was 8%.

Examples 12 and 13 Using the starting materials shown in Table 1, the reaction was carried out in the same manner as in Example 2 to obtain the products shown in Table 1. The results are also shown in Table 1.

Claims (9)

(57) [Claims] (1) General formula [Wherein R ₁ , R ₂ , R ₃ and R ₄ represent the same or different atoms or groups selected from a hydrogen atom, a halogen atom, and a group stable in the reaction medium in the reaction medium], represented by the formula: Or a salt thereof, which is reacted with lead in an acidic medium. [Wherein R ₁ , R ₂ , R ₃ and R ₄ are the same as above]. 2. The general formula A hydroxybenzotriazole represented by the formula (where R ₁ , R ₂ , R ₃ and R ₄ are the same as above) is reacted with lead or a lead compound in an acidic medium in the presence of a metal having a greater ionization tendency than lead. General formula characterized by the following: [Wherein R ₁ , R ₂ , R ₃ and R ₄ are the same as above]. 3. The method according to claim 2, wherein the metal having a higher ionization tendency than lead is aluminum, iron, nickel, tin, cobalt, magnesium or a mixture thereof. 4. The method according to claim 3, wherein the metal having a higher ionization tendency than lead is aluminum. 5. In the general formula (I), the stable group in the reaction medium of R ₁ , R ₂ , R ₃ and R ₄ is an alkyl group, a halogenated alkyl group, an allyl group, an alkoxy group, a carboxyl group, an acyl group. The method according to claim 1 or 2, wherein the method is at least one selected from the group consisting of a group, an amino group, an acylamino group, a sulfoamino group, a carbamoyl group, a sulfamoyl group and a sulfone group. 6. The method according to claim 1, wherein the acidic medium is at least one selected from the group consisting of a mineral acid, an acid salt of a mineral acid, an organic carboxylic acid, an organic sulfonic acid, and an acid anhydride thereof. 3. The method according to claim 2. 7. An acid medium is supplied, and the acidity of the reaction system is adjusted to pH4.
The method according to claim 1 or 2, wherein the method is adjusted as follows. 8. A reaction solvent comprising an acidic medium, water, alcohols,
2. The method according to claim 1, wherein at least one kind of a homogeneous or heterogeneous solvent selected from the group consisting of esters, ethers, hydrocarbons, acid amides and halogenated hydrocarbons is used.
3. The method according to item 2 or 2. 9. The method according to claim 1, wherein the reaction temperature is 0 to 160 ° C.