JPH04316526A - Alkali hydrolysis of carboxylic acid ester - Google Patents

Abstract

PURPOSE:To inexpensively produce an alcohol and an alkali metallic salt of carboxylic acid from a carboxylic acid ester under a mild reaction condition by a short process. CONSTITUTION:In hydrolyzing a carboxylic acid ester with an alkali, the carboxylic acid ester is reacted with a solid alkali metal hydroxide in a substantially solventless state. Since this hydrolysis has a higher reaction rate than conventional hydrolysis of carboxylic acid ester in a solvent and the separation of the solvent from a formed alcohol is not required, this process has low cost.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing alcohols and alkali metal carboxylates useful as chemical products by alkaline hydrolysis of carboxylic acid esters.

0002

[Prior Art] A conventional technique for producing alcohol and alkali metal carboxylate by alkali hydrolysis of carboxylic acid ester. When a carboxylic acid ester is subjected to alkaline hydrolysis to produce an alcohol and an alkali metal carboxylate, the reaction is carried out in a large amount of water solvent.

For example, when producing soap from oils and fats mainly composed of triacylglycerin represented by formula (1), the oils and fats are reacted with caustic soda in a large amount of an aqueous solvent, and then common salt is added to create a high-grade soap using a salting-out effect. Fatty acid sodium salt (soap) is precipitated. For this reason, the produced glycerin remains in the water layer, and the water and glycerin are separated by distillation, but a large amount of energy is wasted in this process. Furthermore, since salt is present, the equipment must be made of special material to prevent corrosion, resulting in high equipment costs.

[0004] For this reason, recently, the most popular method has been to hydrolyze fats and oils without a catalyst and then neutralize the produced higher fatty acids with an alkali. The hydrolysis reaction of fats and oils is an equilibrium reaction, and a large amount of water is used in order to favor the equilibrium relationship, and in order to increase the dissolution of water into the oil phase, 250-27
The reaction is carried out at 0° C. and high temperature and pressure of 700-725 psig. In this case too, a large amount of energy is wasted when separating water and glycerin by distillation. Additionally, equipment costs are high because it involves a harsh high-temperature, high-pressure reaction.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to produce an alcohol and an alkali metal salt of a carboxylic acid from a carboxylic ester under mild reaction conditions in a short process at low cost.

[0006]

[Means for Solving the Problems] As a result of intensive research into solid-phase reactions and solid-liquid reactions, the present inventors have discovered that the alkaline hydrolysis reaction of carboxylic acid esters can be carried out without using a large amount of water as a solvent as in the past. On the contrary, they discovered that by reacting a solid alkali metal hydroxide and a carboxylic acid ester substantially without solvent, the reaction rate was higher and the reaction proceeded more efficiently than in an aqueous solvent, and based on this knowledge, The present invention has been accomplished.

That is, the present invention involves the production of alcohol and alkali metal salts of carboxylic acids by alkaline hydrolysis of carboxylic acid esters, in which the reaction is carried out substantially without solvent and solid alkali metal hydroxides are used as alkali. It's about how to use it. In the present invention, after mixing the ester and the solid alkali metal hydroxide are mixed, the reaction proceeds under mild temperature conditions of about room temperature to about 300°C. The reaction temperature varies depending on the type of alcohol produced by alkaline hydrolysis of the carboxylic acid ester. That is, if the alcohol to be produced has a low boiling point, such as methyl alcohol, the process will proceed satisfactorily even at room temperature. Further, when the alcohol to be produced has a high boiling point such as glycerin, the reaction temperature is preferably about 100 to 250°C. Even if the reaction is carried out at a relatively high temperature, the reaction pressure will not be high because water etc. are not used as a solvent; on the other hand, the reaction may be carried out under normal pressure or reduced pressure while distilling off the alcohol produced. Yes, this method is industrially useful.

If a carboxylic ester is considered to be a dehydration condensation product of an alcohol and a carboxylic acid, the constituent components of the carboxylic ester can be defined as the alcohol and the carboxylic acid. Based on this definition, the carboxylic acid ester used in the present invention will be described below. The range of alcohols that are one component of the carboxylic acid ester used in the present invention is wide;
Alcohol, polyhydric alcohol from divalent to hexavalent, 1
There are hydric phenols, dihydric phenols, etc. These alcohols and phenols have 1 to 40 carbon atoms, and some contain a double bond, a hetero atom, an alicyclic ring, or an aromatic ring in the main chain, and some contain a substituent such as a halogen in the side chain. Examples of these include methyl alcohol, ethyl alcohol,
Normal propyl alcohol, isopropyl alcohol, tert-butyl alcohol, n-hexyl alcohol, n-tetradecyl alcohol, n-eicosyl alcohol, mericyl alcohol, cyclohexyl alcohol, benzyl alcohol, 9-octadecen-1-ol, ethylene glycol, Propylene glycol, tetramethylene glycol, polyethylene glycol, polypropylene glycol, cyclohexane-1,4-diol, glycerin, pentaerythritol, D-sorbitol, D-mannitol, phenol, sotacresol, p
-tertbutylphenol, catechol, hydroquinone, O-chlorophenol and the like.

[0009] The carboxylic acid, which is the other component of the carboxylic acid ester used in the present invention, has a wide range of types, including monobasic acids and dibasic acids, and these carboxylic acids have a carbon number of 1 to 1.
40, and some contain a double bond, a heteroatom, an alicyclic ring, or an aromatic ring in the main chain, and some contain a substituent such as a halogen in the side chain. These include acetic acid, propionic acid, butyric acid, crotonic acid, caproic acid, capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, melisic acid, crotonic acid, 4-dodecenoic acid, and erucic acid. , α-bromocaproic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, benzoic acid, isophthalic acid, etc.

[0010] As described above, since the alcohols and carboxylic acids that constitute carboxylic esters are diverse, there are many carboxylic esters that are combinations of these. However, the esters used in the present invention do not include polyesters obtained by combining polyhydric alcohols and dibasic acids. In the case of carboxylic acid esters of polyhydric alcohols and carboxylic acid esters of dibasic acids, it is not necessary that all hydroxyl groups or carboxyl groups are esterified, and partially esterified ones can also be used in the present invention.

Examples of carboxylic acid esters used in the present invention include ethyl acetate, octadecyl acetate,
Examples include isopropyl butyrate, methyl caproate, methyl laurate, methyl stearate, diethyl succinate, and dimethyl isophthalate. Further, animal/vegetable fats and oils containing triacylglycerin represented by the following formula (1) as a main component are also important carboxylic acid esters used in the present invention.

0012

[Chemical 2]

Examples of vegetable oils include soybean oil, palm oil,
These include sunflower oil, rapeseed oil, cottonseed oil, peanut oil, olive oil, corn oil, camellia oil, cacao oil, pumpkin seed oil, loofah seed oil, sesame oil, and rice bran oil. Examples of animal fats and oils include sardines, oysters, clams, and sardines.
Fats and oils from aquatic animals such as whales, salmon, sharks, saury, walleye, herring, tuna, mackerel, and Japanese daikon daisies; fats and oils from land animals such as ducks, rabbits, cows, pigs, horses, and mink. can be mentioned. Most of the animal and vegetable fats and oils listed here contain unsaturated bonds, and an effective method is to hydrogenate the unsaturated bonds and then perform alkaline hydrolysis.

The alkali used in the present invention is a solid alkali metal hydroxide. Examples of these alkalis include lithium hydroxide, sodium hydroxide, potassium hydroxide, and rubidium hydroxide, all of which are used in solid form. Preferred is solid sodium hydroxide or solid potassium hydroxide. In addition, in the present invention, compounds that become alkali metal hydroxides when hydrolyzed, such as alkali metal hydrides, alkali metal oxides, alkali metal carbonates, alkali metal bicarbonates, alkali metal alcoholates, and alkali metal amides, can also be treated as alkalis. can be used. Examples of these compounds include sodium hydride, sodium oxide, sodium carbonate, sodium hydrogen carbonate, potassium tert-butoxy, potassium carbonate, and the like. When these compounds are used as alkalis, in the case of alkali metal compounds, alkali metal 1
Requires 1 mole of water per atom. The water needed here is
It is preferable to add water gradually to the reaction system, but when carrying out the reaction on a small scale, there is no need to intentionally add water as water in the air is naturally taken in.

[0015] From the viewpoint of reaction rate, it is desirable to use a finely powdered solid alkali compound for use in the present invention. Although a solid alkali compound is used in the present invention, it is not necessary to completely remove the moisture in the solid alkali compound, and an alkali compound in a moisture-absorbed state can also be used as long as it remains solid. .

Embodiments of the present invention are shown below. ■
A hydrolysis method according to the present invention, characterized in that solid sodium hydroxide or solid potassium hydroxide is used as the alkali. ■ In the method of the present invention, the alkali is an alkali metal compound selected from alkali metal hydrides, alkali metal oxides, alkali metal carbonates, alkali metal bicarbonates, alkali metal oxides, alkali metal alcoholates, and alkali metal amides; An alkaline hydrolysis method characterized in that water is used in an amount necessary to hydrolyze an alkali metal compound. (2) An alkaline hydrolysis method characterized in that the method of the present invention uses a finely divided alkali metal hydroxide. ■
In the method of the present invention, an alkaline hydrolysis method characterized in that triacylglycerin represented by the above formula (1) is used as the carboxylic acid ester. (2) An alkaline hydrolysis method characterized in that the method of the present invention is carried out while distilling off the alcohol produced.

[0017]

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples and Reference Examples.

[0018]

Examples 1 to 17 Table 1 shows the carboxylic acid esters, solid alkalis, reaction conditions, reaction times and yields used in Examples 1 to 17. Put 1 g of carboxylic acid ester and a specified amount of solid alkali into a flask, rotate the flask gently for about 10 minutes to uniformly disperse the carboxylic ester and solid alkali, and then place under the reaction conditions shown in Table 1 to achieve the specified amount. After a period of time, dilute hydrochloric acid was added to the reaction product, and the precipitated carboxylic acid was suction filtered, washed with water, dried, and then quantified to determine the yield. In Examples 1 to 16, the solid alkali was used in an equimolar amount relative to the carboxylic acid ester.

In Example 17, potassium hydroxide was used in a molar amount 1.5 times that of methyl benzoate. As the carboxylic acid ester, a commercially available first grade product was used as it was without any particular purification. Further, a solid alkali was prepared and used as follows. Sodium hydroxide: 97% granular sodium hydroxide manufactured by Hayashi Junyaku Co., Ltd. was finely ground in a magnetic mortar and used.

Potassium hydroxide: Wako Pure Chemical Industries, Ltd. 8
5% granular potassium hydroxide was finely ground in a magnetic mortar and used.

[0021]

[Reference Examples 1 to 5] In Reference Examples 1 to 5, the same reactions as in Examples 1 to 20 were carried out. However, sodium hydroxide was used as the alkali, and it was dissolved in 20 ml of the solvent shown in Table 2 before use. The results are shown in Table 2. As is clear from the comparison of Example 2 and Reference Example 1, Example 7 and Reference Example 2, Example 9 and Reference Example 3, Example 14 and Reference Example 4, and Example 16 and Reference Example 5, The yield is overwhelmingly higher when it is not used at all, and the remarkable effects of the present invention can be understood.

[0022]

[Example 18] 1.20 g of sodium hydroxide is ground in a magnetic mortar, and 8.77 g of olive oil is added thereto. This mixture is mixed well and placed in a kugel flask. After attaching the flask to the kugel, rotate the flask gently for about 15 minutes to further mix the sodium hydroxide and olive oil. After that, 15 flasks of Kugel
The mixture was placed in an oil bath at 5° C., and the pressure was reduced to 9 mmHg, and the reaction was carried out while distilling off the alcohol produced. 0.47g of glycerin was distilled out in 6 hours. After cooling Kugel's flask, it was washed 5 times with a small amount of toluene to remove undistilled glycerin and a very small amount of olive oil, and then washed 5 times with a small amount of water to obtain a milky white higher fatty acid sodium salt. 6.17g of (soap) was obtained.

In the infrared absorption spectrum of the soap produced, there is no ester absorption near 1780 cm-1, and 1
Absorption of carboxylic acid sodium salt was observed near 600 cm-1.

[0024]

Example 19 The same operation as in Example 18 was carried out. However, 1.05 g of sodium hydroxide was used and 6.9 g of beef tallow was used instead of olive oil. The amount of glycerin distilled out was 0.21 g, and the amount of soap was 6.97 g.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

According to the present invention, compared to conventional alkali hydrolysis of carboxylic esters in a solvent, a milder reaction and a shorter process can be used to convert carboxylic esters into alcohols and alkali metals of carboxylic acids. Salt can be manufactured.

Claims (3)

[Claims] [Claim 1] A process characterized by using a solid alkali metal hydroxide as the alkali and carrying out the reaction substantially without a solvent when producing an alcohol and a carboxylate by alkali hydrolysis of a carboxylic acid ester. Alkaline hydrolysis method of carboxylic acid ester. [Claim 2] An alkali metal compound selected from alkali metal hydrides, alkali metal oxides, alkali metal carbonates, alkali metal bicarbonates, alkali metal oxides, alkali metal alcoholates, and alkali metal amides as the alkali, and these alkalis. The alkaline hydrolysis method according to claim 1, characterized in that water is used in an amount necessary to hydrolyze the metal compound. [Claim 3] The following (1) as carboxylic acid ester:
The alkaline hydrolysis method according to claim 1, characterized in that a triacylglycerol represented by the formula is used. [Chemical formula 1]