JPS6141329B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing unsaturated glycols from conjugated dienes. More specifically, the present invention relates to a method for producing unsaturated glycols by oxidizing conjugated dienes in the presence of water. The unsaturated glycols produced by the present invention are important as intermediates for various chemical products.
In particular, 2-butene-1,4-diol and 1-butene-3-diol produced from 1,3-butadiene
4-Diol is an important chemical product from which industrially useful 1,4-butanediol, tetrahydrofuran, etc. are produced through operations such as isomerization, hydrogenation, and dehydration. The following methods are known as known methods for producing these unsaturated glycols. (1) A method in which simple chlorine is added to conjugated dienes and then treated with alkali. (2) A method in which conjugated dienes are oxidized in a carboxylic acid in the presence of a catalyst such as palladium to produce an unsaturated glycol diester, which is then hydrolyzed. (3) A method in which formalin is added to acetylene and then hydrogenated. These methods are not necessarily economical manufacturing methods because of the complicated operations, the consumption of a large amount of energy, and the high cost of raw materials. The present inventors have conducted intensive research to develop a method for producing unsaturated glycols more efficiently and economically than using inexpensive conjugated dienes. They discovered a method for producing glycols and completed the present invention. That is, according to the present invention, the general formula () (In the general formula (), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are hydrogen or hydrocarbon residues.) expressions (), () and ()

【formula】

【formula】

[Formula] (R ₁ , R ₂ in general formulas (), () and (),
The definitions of R ₃ , R ₄ , R ₅ and R ₆ are the same as in the general formula (). ) To produce unsaturated glycols represented by Unsaturated glycols can be easily obtained by carrying out the reaction in the presence of at least one component selected from the following. According to the present invention, unsaturated glycols can be obtained in a substantially one-step reaction under milder reaction conditions than those of inexpensive conjugated dienes, making it possible to produce unsaturated glycols very economically. The present invention will be explained in more detail below. The conjugated dienes used in the present invention are represented by the above general formula (). There is no particular restriction on the above conjugated dienes, but preferably
R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ have 6 carbon atoms
The following alkyl groups are preferred. Also,
Two groups selected from R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ may be linked to each other to form a cyclic compound. Furthermore, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆
is an alkoxy group, a nitrogen-containing substituent, a carbonyl group,
It may also be a hydrocarbon residue substituted with a substituent that is substantially inert to this reaction, such as a hydroxyl group. Examples of these conjugated dienes include 1,3-butadiene, isoprene, 1,3-pentadiene,
1,3-hexadiene, cyclopentadiene,
Examples include 1,3-cyclohexadiene,
It is not limited to these. The iodine used in the present invention does not necessarily need to be added as simple iodine, but as an iodine-containing substance that produces simple iodine in the reaction system or an iodine-containing composition that produces simple iodine in the reaction system. May be added. Examples of iodine-containing substances that produce simple iodine in the reaction system include complex compounds containing simple iodine, I ^- ₃ ions, and iodine oxides that produce simple iodine when reduced by reaction with conjugated dienes (e.g., (iodic acid or its salts, etc.). Examples of iodine-containing compositions that produce elemental iodine in the reaction system include (a) hydriodic acid, metal iodides, and organic iodides that produce iodine ions through solvent displacement reactions (such as allyl iodide or iodine). Examples include combinations of iodine compounds such as isopropyl chloride, etc. and (b) metal compounds with oxidizing power such as cupric salts and ferric salts, and oxidizing agents such as nitrogen oxides, molecular oxygen, and simple chlorine. . There are no particular limitations on the method of adding copper ions, iron ions, and thallium ions used in the present invention, but examples include carboxylic acid, sulfonic acid, sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, etc. It is preferable to add it as a salt with an acid or as a complex of those salts. Under the mild reaction conditions employed in the present invention, the reaction of the present invention proceeds smoothly due to the concerted action of the combination of the above iodine species and the above metal ions; Almost no reaction occurs in the presence of the above metal ions or in the presence of only the above metal ions. Further, the reaction of the present invention is a stoichiometric reaction when no oxidizing agent is added, but a catalytic reaction becomes possible by adding an oxidizing agent such as nitrogen oxide or molecular oxygen. As the oxidizing agent used in the present invention, inexpensive molecular oxygen is advantageous. Although the mechanism of action of copper ions, iron ions, and thallium ions in the present invention is not clear, these metal ions are significant additions in both stoichiometric reactions and catalytic reactions in the presence of an oxidizing agent. Show effectiveness. In the case of a catalytic reaction in the presence of an oxidizing agent, these metal ions are thought to act as a reoxidation catalyst for the iodine ions generated by the reduction of simple iodine, but the stoichiometric amount in the absence of an oxidizing agent It is a surprising fact that it shows a remarkable addition effect even in theoretical reactions, which could not be expected from conventional knowledge. There are no particularly strict restrictions on the pH of the reaction solution of the present invention, and although the reaction proceeds smoothly even near neutrality, an acidic region is preferable, and a particularly preferable pH is
=0.5-7 is preferable. In the reaction of the present invention, the addition of catalyst components other than those listed in the claims is not necessarily necessary, but the addition of bromide ions, chloride ions, and nitrogen oxides improves the activity and catalyst life. These activators can be used as appropriate depending on the type of catalyst. Bromine ion sources used in the present invention include, for example, metal bromides such as hydrobromic acid, potassium bromide, sodium bromide, and copper bromide, which easily generate bromine ions by a solvate displacement reaction under the present reaction conditions. Examples include allyl bromide produced, organic bromides such as bromine adducts of conjugated dienes, ammonium salts of hydrobromic acid, and simple bromine that dissolves in water and generates bromine ions. Examples of chlorine ion sources include metal chlorides such as hydrochloric acid, potassium chloride, sodium chloride, and copper chloride, ammonium salts of hydrochloric acid, and simple chlorine that dissolves in water to generate chlorine ions. . Examples of nitrogen oxides used in the present invention include nitric acid, nitrates such as lithium nitrate, potassium nitrate, and copper nitrate;
Examples include nitrites such as sodium nitrite. The reaction of the present invention is usually carried out in the liquid phase. Although a solvent other than water is not necessarily required for this reaction, a substantially inert solvent can also be used for this reaction. In particular, the use of organic solvents that are compatible with water, such as acetonitrile, acetone, pyridine, ethylene glycol, and butenediol, is an effective method for increasing the solubility of conjugated dienes. The present invention can be carried out under normal pressure or elevated pressure, and in the case of elevated pressure, it is preferably carried out at a pressure of 150 Kg/cm ² or less. Although it is not always necessary to use a diluent gas during this reaction, gases such as nitrogen and carbon dioxide that do not adversely affect this reaction can also be used as the diluent gas. The reaction of the present invention is characterized in that it proceeds easily even at low reaction temperatures. Furthermore, since the unsaturated glycols obtained by the reaction of the present invention are thermally unstable, reaction at high temperatures is not appropriate. Therefore, the reaction temperature is usually preferably 30 to 200°C.
The temperature is particularly preferably 50 to 150°C. When carrying out the present invention, the amount of catalyst can be selected arbitrarily, but normally the amount of simple iodine is preferably 10 to 200 g per reaction solution 1, and the amount of compounds containing copper ions, iron ions, or thallium ions is determined depending on the molecular weight. Although it varies depending on the weight, 10 to 500 g is preferable. The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. Example 1 In a 200 ml four-necked flask equipped with a stirrer, thermometer, reflux condenser and gas inlet tube, 6.35 g (50 milligram atoms) of iodine and cupric chloride (CuCl ₂ 2H ₂ O) were added. 8.52 g (50 mmol), 50 ml of acetonitrile and 50 ml of water were heated to 70°C, and then 40 ml/each of 1,3-butadiene and oxygen were added.
It was supplied at a flow rate of min. After 4 hours of reaction, the reaction solution was analyzed by gas chromatography, and it was found that 1
-Butene-3,4-diol 10.88g and 2-
0.96 g of butene-1,4-diol was produced. Comparative Example 1 The same operation as in Example 1 was carried out, but cupric chloride was not used. As a result, 1-butene-3.
Almost no 4-diol or 2-butene-1,4-diol was produced. Example 2 The same operation as in Example 1 was carried out, except that 4.95 g (50 mmol) of cuprous chloride (CuCl) was used instead of cupric chloride, and the reaction was carried out for 1 hour. The results are shown in Table 1. Example 3 The same operation as in Example 1 is carried out, but thallium chloride (TlCl ₃ 4H ₂ O) is used instead of cupric chloride.
Using 19.14 g (50 mmol), the reaction was carried out for 2 hours. The results are shown in Table 1. Example 4 The same operation as in Example 1 was carried out, but ferric nitrate (Fe(NO ₃ ) _{3.9H 2} O) was used instead of cupric chloride.
20.20 g (50 mmol) was used and the reaction was carried out for 2 hours. The results are shown in Table 1. Example 5 The same operation as in Example 1 was carried out, but without supplying oxygen, 11.17 g (50 mmol) of cupric bromide (CuBr ₂ ) was used instead of cupric chloride, and the reaction was continued for 1 hour. I did it. The results are shown in Table 1. Example 6 The same operation as in Example 5 was carried out, except that 7.17 g (50 mmol) of cuprous bromide (CuBr) was used instead of cupric bromide, and the reaction was carried out for 2 hours. The results are shown in Table 1. Example 7 The same operation as in Example 5 is carried out, but cupric nitrate (Cu(NO ₃ ) _{2.3H 2} O) is used instead of cupric bromide.
Using 12.08 g (50 mmol), the reaction was carried out for 2 hours. The results are shown in Table 1. Example 8 The same operation as in Example 5 was carried out, except that 8.30 g (50 mmol) of potassium iodide was used instead of iodine, and the reaction was carried out for 2 hours. The results are shown in Table 1. Example 9 The same operation as in Example 1 was carried out, except that 6.40 g (50 mmol) of hydrogen iodide was used instead of iodine, and the reaction was carried out for 2 hours. The results are shown in Table 1. Example 10 The same procedure as in Example 9 was carried out, except that 4.96 g (50 mmol) of cuprous chloride (CuCl) was used instead of cupric chloride. The results are shown in Table 1. Example 11 Example 1 was carried out using a solution of 8.30 g (50 mmol) of potassium iodide and 12.08 g (50 mmol) of cupric nitrate (Cu(NO ₃ ) 2.3H ₂ O) dissolved in 100 ml _of water.
The reaction was carried out for 1 hour in the same manner as above. As a result, 0.12 g of 1-butene-3,4-diol and a small amount of 2-butene-1,4-diol were produced. Example 12 5.95 g (50 mmol) of potassium bromide and 3.45 g (50 mmol) of lithium nitrate were further added to the system of Example 11, and a reaction was carried out in the same manner as in Example 11 for 1 hour. As a result, 1-butene-3,4-diol
0.32 g and 0.12 g of 2-butene-1,4-diol were produced. Example 13 The same operation as in Example 12 was carried out, but instead of 100 ml of water, a mixed solvent of 50 ml of water and 50 ml of acetonitrile was used to conduct the reaction for 1 hour. As a result, 1-
Butene-3,4-diol 1.83g and 2-butene-
0.75 g of 1,4-diol was produced. Example 14 The same procedure as in Example 13 was carried out, except that 6.35 g (50 milligram atoms) of iodine was used instead of potassium iodide and the reaction was carried out for 1 hour. the result,
1.63 g of 1-butene-3,4-diol and 0.52 g of 2-butene-1,4-diol were produced. Example 15 Perform the same operation as Example 12, but use ferric nitrate (Fe(NO ₃ ) ₃ 9H ₂ O) instead of cupric nitrate.
The reaction was carried out using 20.20 g (50 mmol) for 1 hour. As a result, 0.81 g of 1-butene-3,4-diol and a small amount of 2-butene-1,4-diol were produced. Comparative Example 2 The same operation as in Example 13 was carried out, but without using cupric nitrate. As a result, 1-butene-3.
Almost no 4-diol or 2-butene-1,4-diol was produced. Comparative Example 3 The same operation as in Example 11 was carried out, but 5.95 g (50 mmol) of potassium bromide was used instead of potassium iodide. As a result, only trace amounts of 1-butene-3,4-diol were produced. Comparative Example 4 The same operation as in Example 11 was carried out, except that 2.00 g (25 mmol) of simple bromine was used instead of potassium iodide. As a result, trace amounts of 1-butene-3.
Only 4-diol was produced. Comparative Example 5 The same operation as in Comparative Example 1 was carried out, but the reaction was carried out by adding 5 mmol of nitric acid. As a result, 1-butene-3,4-diol and 2-butene-1,
Almost no 4-diol was produced in either case.

【table】

Claims (1)

[Claims] 1. In producing unsaturated glycols by oxidizing conjugated dienes in the presence of water, (A) simple iodine, an iodine-containing substance or composition that produces simple iodine in the reaction system; 1. A method for producing unsaturated glycols, characterized in that the reaction is carried out in the presence of at least one component and (B) at least one component selected from copper ions, iron ions, and thallium ions. 2. The method according to claim 1, wherein the reaction is carried out in the presence of molecular oxygen.