CS216044B1 - Method of continuous preparation of the benzylalcohol - Google Patents

Description

Process for the continuous preparation of benzyl alcohol

The invention relates to the preparation of benzyl alcohol by the hydrolysis of benzyl chloride. The hydrolysis is carried out with aqueous solutions of alkali metal carbonates or hydroxides. There are also side reactions, which also include ethyl ether and benzaldehyde. Part of the benzyl chloride remains unreacted in the reaction mixture.

The production of benzyl alcohol by the hydrolysis of benzyl chloride is carried out discontinuously in a stirred reactor and continuously in tubular and special flow reactors.

The discontinuous process is relatively costly and shows the idea of labor productivity. The design of the nickel-alloy reactor for the above-mentioned temperature and pressure para-parameters requires considerable investment costs *.

The disadvantages of both methods are eliminated by the continuous preparation of benzyl alcohol by hydrolysis of benzyl chloride with an aqueous solution of alkali metal carbonates or hydroxides according to the invention, the principle being that the hydrolysis is carried out in 2 to 4 connected compartments at 90 ° C. up to 150 ° C at atmospheric pressure up to 1.4 MPa, while the reaction mixture is stirred to create turbulence, characterized by specific

0.5 to 20 kW / L of useful reaction space.

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The advantage of this process for the preparation of benzyl alcohol is that the reaction conditions are such that it is possible to use a commercially available equipment for production, which does not require any extra investment costs.

In order to illustrate the invention, the following examples are given.

Example 1 (percentages are percentages by weight)

The continuous production of benzyl alcohol by the hydrolysis of benzyl chloride is carried out by a device consisting of two enamelled jacketed reactors with an internal diameter of 300 and a total height of 493 mm, provided with an overflow of 295 mm, thus defining a reaction space of 20 ± 0.2 liters. The reactor is equipped with a six-blade stirrer 6 with straight, oblique blades. The stirrer has 1,000 rpm and the specific power delivered by the liquid stirrer is 4.1 kW / m < 3 >.

Each reactor is equipped with a 0.3m water-cooled reflux condenser, thermometer and pressure gauge. Dosing of components is ensured by infinitely adjustable dosing units *! pumps. The produced product falls into a pressure tank equipped with a pressure gauge and an adjustable degassing valve.

In both reactors and 17.3 kg of a 9.75% soda solution, 3.2 kg of benzyl chloride are introduced, mixing with steam heating is started in the reactor jacket. After heating at 95-98 ° C for 4 h while maintaining this temperature and atmospheric pressure, 480 £ 20 c / P of benzyl chloride and 2580 ± 50 cc / f of an aqueous soda solution are introduced into the first reactor. The apparatus produces 389 g / h of an organic layer containing 1.21% benzyl chloride, 7.23% benzyl ether, 2.66% benzaldehyde, 86.88% benzyl alcohol, and 2830 g / h aqueous layer containing 3.01% benzyl alcohol. The total yield of benzyl alcohol is 95.5% of theory.

Example 2

While keeping the apparatus and procedure described in Example 1, the reactors filled with the reaction mixture are heated to a temperature of 112 to 115 ° C at a pressure of 1 to 5 bar. 960 ± 20 cc / h of benzyl chloride and 5160 + 50 cc / h of aqueous soda solution were dosed to the Doreactor at these parameters.

775 g / h of an organic layer are obtained which contains 1.30% benzyl chloride, 6.88% benzyl ether, 2.73% benzaldehyde, 89.09% benzyl alcohol and 5,560 g / h of an aqueous layer containing 2.96% benzyl alcohol. Total yield of benzyl alcohol. is 95.0% of theory ·

Example 3 *

While maintaining the apparatus and procedure of Example 1 ee, the soda pitch was dosed with 2,630 cm @ 2 / cc of an aqueous solution of potassium carbonate at a concentration of 12.4, 2,555 cm @ 2 / h of an aqueous NaOH solution at 4.0% and 2,575 cm @ 2. h of aqueous solution of KOK at a concentration of 5.4 fc.

The reaction compositions and yields were identical to the values given in Example 1 using the compounds within the standard deviation.

Example 4

The benzyl alcohol production plant by hydrolyzing benzyl chloride in the presence of an inert solvent consists of three enamelled jacketed reactors with the same equipment as in Example 1.

Each of the three reactors was charged with 2.5 kg of benzlyl chloride, 2.5 kg of chlorobenzene and 16 kg of a 10 wt.% Soda solution, started with an agitator and heated. After XO hours, heating to 97-100 ° C was started. to a first reactor of 640 + 20 cm @ 2 / h of a mixture of benzyl chloride and chlorine. benzene in wt. ratio of 1: 1 and 1,710 + 50 cm / h aqueous soda solution at a concentration of 10 wt. The plant produces 652 g / h of organic layer containing 1.41% benzylchloride, 1.16% benzyl ether, 1.40% benzaldehyde, 42.17% benzyl alcohol, 50.90% chlorobenzene, and 1,870 g / h aqueous layer containing 0.62 % phthenzyl alcohol. The total yield of benzyl alcohol is 95.2% of theory.

Claims (1)

A process for the continuous preparation of benzyl alcohol by the hydrolysis of benzyl chloride with an aqueous solution of alkali metal carbonates or alkali metal hydroxide, optionally; in the presence of an auxiliary inert organic solvent, characterized in that the hydrolysis is carried out at a temperature of 90 to 150 ° C at atmospheric pressure up to 1.4 MPa in 2 to 4 connected compartments with stirring of the reaction mixture, the specific power being transferred to the liquid is 0.5 and 20 kW / a of useful reaction space.