JPS6030663B2 - Production method of tertiary alkyl hypohalite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing tertiary alkyl hypohalite, and particularly to a method for producing tertiary alkyl hypochlorite.

The reaction between a tertiary alkanol, chlorine and an aqueous base to produce tertiary alkyl hypochlorite is generally known to those skilled in the art, for example from US Pat. .

US Pat. No. 4,008,133 describes the production of tertiary-butyl hypochlorite in a general process for producing olefin oxides. The reaction between a halogen, a base, and a tertiary alkanol to make tertiary alkyl hypohalites is a highly exothermic reaction that requires external cooling and is not effective in processes such as those shown in the above-mentioned U.S. patents. Difficulties are encountered when planning to economically dissipate the heat of reaction to provide reliable temperature control. Ineffective temperature control can cause decomposition of the tertiary alkyl hypochlorite, resulting in yield losses and sometimes leading to uncontrolled reactions, such as runaway reactions. According to the present invention, a new and improved process for producing tertiary alkyl hypohalites by reaction of a tertiary alkanol, a halogen and an aqueous base overcomes the temperature control difficulties of conventional processes as described above. I will provide a.

According to the present invention, a tertiary alkanol is combined with a halogen and an aqueous inorganic base, and/or a prehalogenated aqueous inorganic salt, and the tertiary alkyl hypohalite product is evaporated, typically at a temperature below 100°C. The tertiary alkyl hypohalite is produced by the reaction at a pressure that recovers the tertiary alkyl hypohalite as a vapor product.

The heat of reaction is removed as latent heat (evaporation of the product), resulting in self-control of the reaction temperature. More specifically, the reaction is generally carried out under reduced pressure, generally at pressures on the order of 5 to 100 kPa, most commonly on the order of 20 to 60 kPa.

The reaction temperature is from just above the freezing point, usually up to 100°C, preferably up to 60°C, most preferably between 40 and 6000°C.
It can be a stand. As previously stated, pressure is adjusted along with temperature to ensure evaporation of the hypochlorite ester product. According to a preferred embodiment, the reaction is a continuous reaction, in which an aqueous solution of tertiary alkanol, halogen and inorganic base and/or tertiary alkanol and another halogenated aqueous base are continuously fed to the reactor and the evaporated hypohalogen The tertiary alkyl acid and generally a small amount of water vapor are also continuously removed from the reactor.

The reactor can be any one of a variety of reactors that provide good contact between the reaction components, particularly those suitable for gas-liquid reactions. Particularly simple and useful is a deep tank type reactor in which the reactants are introduced into a liquid composition of the reactants, simulated by bubbles of evaporating hypohalite ester. According to a particularly preferred embodiment, the reactor is adapted to remove the heat generated by the chemical reaction by vaporizing the tertiary alkyl hypohalite product and generally also vaporizing small amounts of water and/or alkanol. Maintain heat balance by suppressing pressure.

In this method there is no need for external cooling of the reaction medium to maintain the reaction temperature. According to a preferred embodiment, therefore, the reaction is carried out under essentially isothermal conditions, ie the reaction temperature does not vary by more than a few degrees centigrade over the reactor. The tertiary alkanol used as a reaction component is preferably tertiary butyl or tertiary amyl alcohol, particularly tertiary butanol.

The aqueous inorganic base can be any one of a variety of bases including alkali metal and alkali metal hydroxides, with sodium hydroxide, potassium hydroxide and calcium hydroxide being particularly preferred, with sodium hydroxide being the most preferred. preferable. Each reaction component is used in a wide range of proportions depending on the desired reaction result.

For example, when it is desired to obtain substantially complete conversion of any desired reaction component, excess of the other reaction component may be used. Generally, it is preferred to use approximately the stoichiometric proportions, that is, approximately equimolar amounts. For example, to minimize the presence of halogen in the hypohalite vapor product, the molar ratio of halogen to base should not exceed about 1.05:1. The amount of halogen in the hypohalite ester vapor product is determined by providing one or more additional stages in which the vapor exiting the reactor is contacted with an aqueous base to remove the halogen by forming a hypohalite ester. can be reduced by Similarly, in order to prevent the presence of organics, such as tertiary alkanols, in the aqueous phase recovered from the reactor, the amount of tertiary alkanol to base should not be much, if any, higher than the theoretical ratio; In some cases, the ratio should be lower than the theoretical ratio.

For example, the ratio of tertiary alkanol to base is typically 0.95:
1 to 1.3:1, most preferably 0.98:1
~1.05:1 unit. Large amounts of tertiary alkanol may be used if desired; such large amounts do not adversely affect the reaction.

Although the present invention may be used generally for the production of hypochlorite esters, or hypobromic acid esters and hypoiodite esters, which are sufficiently stable under the reaction conditions, the present invention is particularly applicable to hypochlorite esters, especially Applicable to the production of tertiary butyl hypochlorite.

The present invention will hereinafter be explained with reference to hypochlorite ester. The present invention is particularly useful in all processes for producing olefin oxides, such as those using tertiary alkyl hypochlorite to produce chlorohydrins by reaction with olefins and water. Such methods are described, for example, in US Pat. No. 4,008,13.
It is stated in No. 3. For example, according to such a preferred embodiment, chlorine generated in the electrolytic cell as well as an electrolyte obtained from an aqueous solution of sodium chloride and sodium hydroxide in an aqueous solution of sodium chloride and sodium hydroxide is combined with a tertiary alkanol at a temperature as described above and a pressure as described above. tertiary alkyl hypochlorite is recovered as vapor, and the heat of reaction is removed by evaporation of the tertiary alkyl hypochlorite product and some water. The reaction temperature is controlled by The aqueous phase, which is an aqueous sodium chloride solution, is recycled to the electrolytic cell after appropriate treatment if necessary. The tertiary alkyl hypochlorite vapor is then used in a chlorohydrination reactor as described in U.S. Pat. No. 4,008,133 to produce olefin chlorohydrin. Alternatively, all or part of the electrolyte is prechlorinated and the prechlorinated electrolyte is reacted with a tertiary alkanol to produce tertiary alkyl hypochlorite, which is recovered as a vapor as described above.

The present invention will be further explained with reference to the following examples.

Example diameter: 5.08 meters (2n), height: 91.4 arcs (gt
) The reactor was constructed from tubes.

The lower part of the tube was emptied and provided with an inlet for gaseous chlorine, liquid t-butanol, and an aqueous solution containing 12% NaOH and 15% NaCI. This solution contains approximately 25% NaCI
It simulated the bath liquid generated from electrolysis of an aqueous solution. Above the tube 15.
A 24-ring (1/8 inch) was filled with a 3.81 inch (1/8 inch) Raschig ring.

The filling prevents entrainment of droplets. An outlet for the vapor reaction products was made above the packing. An outlet is provided in the center of the packed zone through which a stream of tank liquid is introduced to contact the vapor exiting the reactor and thus remove unreacted chlorine from the effluent gas. An outlet placed 1.8 t above the bottom of the reactor served as an overflow for the aqueous sodium chloride solution and was connected to a receiver.

The product vapor exiting through the top of the reactor was condensed in two cooling traps in series (ice water and dry ice). The final cooling trap was connected to a vacuum pump. The column was electrically surrounded for heating and equipped with the necessary equipment for vacuum operation.

The experiment was started by introducing 600 cc of 25% by weight NaCI aqueous solution into the reactor.

The temperature was 45°C and a pressure of 37kpa (280°C absolute pressure) was established. By metering pump, t-Bu
1 [/min (10.5 skin mol/min) flow of OH and 3
．． 05/min of bath liquid was fed to the reactor.

Gaseous chlorine (270 g/min, 11 mmol/min) was bubbled into the reactor liquid. Approximately 80% of the sludge was fed to the bottom of the reactor and the remainder was pumped into the packing zone. The molar ratio between each reaction component is 1. Yamaichi BuOCI/1.04NaOH/1.
I kept it at 0 to 12.

The contents of the reactor were mixed intensively by the air bubbles that formed. By maintaining the pressures mentioned above, there were no problems in avoiding overheating of the reaction mixture. No liquid organic phase was seen within the reactor.

The contents of the trap were analyzed at the end of the test. The organic phase consisted of essentially pure t-BuOCI. The present invention is particularly advantageous in that it allows the production of tertiary alkyl hypochlorite while controlling the temperature economically to prevent runaway reactions that sometimes occur.

Claims (1)

[Claims] 1. Tertiary alkanol at a temperature and pressure that vaporizes the tertiary alkyl hypohalite product during the reaction, controls the reaction temperature, and recovers the tertiary alkyl hypohalite as a vapor product. A method for producing tertiary alkyl hypohalite, which comprises reacting with an aqueous solution of a halogen and an inorganic base, or reacting with an aqueous solution of an inorganic base reacted with a halogen. 2. The method according to claim 1, wherein the reaction pressure is reduced pressure. 3. The method according to claim 2, wherein the halogen is chlorine for producing tertiary alkyl hypochlorite. 4. The method of claim 3, wherein the reaction is carried out at a pressure that removes the heat of reaction by evaporation, thereby controlling the reaction temperature to essentially isothermal conditions without external cooling. 5. The method according to claim 4, wherein the tertiary alkanol is tertiary butanol. 6 Claim 5 where the pressure is 5 to 100 kPa
The method described in section. 7 Claim 6 in which the reaction temperature is 40 to 60°C
The method described in section. 8. A patent claim in which a reaction component is continuously introduced into a liquid consisting of the reaction component that is stirred by bubbles of the evaporating hypohalite ester, and the vapor containing the hypohalite ester is continuously recovered. The method described in item 7. 9. The method according to claim 1, wherein the base is potassium hydroxide, sodium hydroxide or calcium hydroxide.