JPH01141803A - Production of iodine monochloride - Google Patents

Abstract

PURPOSE:To produce a product of high, constant purity with little loss of chlorine when iodine and chlorine are brought into a reaction to produce iodine monochloride by absorbing excess chlorine in liq. iodine monochloride and adding solid iodine. CONSTITUTION:When iodine monochloride is produced with gaseous chlorine and solid iodine, excess chlorine is blown into liq. iodine monochloride. The liq. iodine monochloride reacts readily with the chlorine and becomes iodine trichloride. After part of the liq. iodine monochloride is converted into iodine trichloride, solid iodine is added. The iodine trichloride is rapidly converted into iodine monochloride and uniform iodine monochloride is obtd. in the liquefied state. The loss of chlorine is hardly caused and the amt. of iodine required can be calculated from the amt. of chlorine blown, so high purity iodine monochloride can be produced and distillation or other refining is made unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing iodine monochloride, which is widely used as an organic iodinating agent, an oxidizing agent, and for measuring the iodine value of fats and oils.

[Problems to be solved by conventional technology and invention]

It is known to react iodine and chlorine to produce iodine monochloride. As a specific example, ■ a method of flowing dry gaseous chlorine over solid iodine (inorganic senthesis Vo.
l, 9.130-133), ■ A method of dissolving or suspending iodine in an organic solvent such as carbon tetrachloride, chloroform, methanol, acetic acid, etc., and flowing gaseous chlorine (West German Patent No. 1961289), ■ Liquid Adding iodine to chlorine,
Alternatively, a method of adding liquid chlorine to iodine (inorganic synthesis)
) Vol, 1 +165-167).Other methods for producing iodine monochloride that do not use chlorine include methods using hydrochloric acid gas and iodine, and methods using potassium iodide and iodate salts (
method using sodium iodate, potassium iodate) (Journal of the American Chemical Society)
Chemical 5ociety) Vol, 7
8.3210 to 3216) are known, but they are not as useful in industrial production as the method using chlorine because of the by-product of hydriodic acid and the high cost of raw materials.

Among the methods for reacting iodine and chlorine, method (2) requires keeping the reaction temperature relatively low in order to increase the solubility of chlorine in the solvent, and chlorine exceeding the solubility remains unreacted and is removed from the reaction system. This makes it difficult to control the reaction based on the amount of chlorine, and since a certain solvent is used, it is difficult to use it for other solvents, which is not desirable in terms of versatility. Method ■ uses liquid chlorine, so
Pressurized operation or a temperature below the boiling point of chlorine is required.
The manufacturing equipment will be special.

The reaction between iodine and chlorine proceeds extremely rapidly and exothermically. For this reason, iodine monochloride can be sufficiently produced in both gas and solid form. However, in method (2), dry chlorine is poured over solid iodine to cause the reaction to occur, making it difficult for more than a certain amount of chlorine to be consumed. Because chlorination of iodine is
Without stopping at the iodine monochloride stage, chlorination proceeds further to form solid iodine trichloride, creating a solid iodine trichloride layer on the mixture of iodine and iodine monochloride that has not completely liquefied. Therefore, chlorination of unreacted iodine is inhibited. In this state, it becomes difficult to adjust the purity of iodine monochloride depending on the amount of chlorine introduced.

In the production of iodine monochloride, it is very important to obtain it in high purity and at a constant purity. If the amount of chlorine introduced is too small, an excess of iodine will occur; if it is too large, an excess of chlorine will occur, easily producing iodine trichloride. In particular, the presence of iodine trichloride produced in a state of excess chlorine causes great harm when iodine monochloride is used as an iodizing agent. This is because iodine trichloride acts as a chlorinating agent and as an oxidizing agent even stronger than iodine monochloride.

Therefore, in order to obtain iodine monochloride of high purity and constant purity, it is necessary to perform distillation or recrystallization using high purity iodine monochloride as a solvent, which is not convenient from an operational point of view.

Furthermore, iodine trichloride, which has a high sublimability, is easily carried by unreacted chlorine and flows out of the reaction system, resulting in loss of iodine and chlorine.

[Means and effects for solving the problems] As a result of intensive studies to solve the above problems, the inventors of the present invention have found that by injecting excess chlorine into iodine monochloride, some of it is converted to iodine trichloride. The present inventors discovered that the object of the present invention could be achieved by subsequently introducing solid iodine, leading to the completion of the present invention.

That is, the present invention provides a method for producing iodine monochloride consisting of gaseous chlorine and solid iodine, which is characterized in that after excess chlorine is absorbed into liquid iodine monochloride, solid iodine is added. This is a method for producing iodine chloride.

Iodine monochloride and chlorine easily react to form iodine trichloride. As mentioned above, the presence of iodine trichloride in iodine monochloride causes adverse effects when using iodine monochloride. In liquid iodine monochloride, iodine trichloride exists uniformly, and upon addition of solid iodine, it quickly becomes iodine monochloride. In this case, 1 mole of iodine trichloride becomes 3 moles of iodine monochloride due to 1 mole of iodine molecules. For this purpose, 50% of iodine monochloride
% to iodine trichloride, and by simply adding iodine, it is possible to easily obtain twice the amount of iodine monochloride as initially charged.

Further, by absorbing chlorine in the form of iodine trichloride into a stirrable liquid iodine monochloride and adding iodine, uniform iodine monochloride can be obtained in a liquefied state.

Specifically, the concentration at which iodine monochloride can exist as a liquid,
Preferably, 50% or more of iodine monochloride is injected with chlorine.

The temperature at which the mixture is introduced is such that iodine monochloride exists as a liquid, preferably in the range of 20 to 40°C. An appropriate amount of chlorine passed through a suitable drying agent, such as sulfuric acid, is absorbed while stirring to convert a portion of iodine monochloride into iodine trichloride.

An amount of iodine calculated from the amount of chlorine is added to the mixture of iodine trichloride and iodine monochloride to adjust the amount of iodine monochloride. In the production of iodine monochloride using this method, there is almost no loss of chlorine, and the required amount of iodine can be calculated from the amount of chlorine flowing in.
High purity iodine monochloride can be obtained after iodine addition.

Therefore, distillation and other purifications that are normally required when producing iodine monochloride using iodine and chlorine are not necessary, and the process can be simplified. Further, by leaving only the amount of iodine monochloride required for the next reaction in the reactor after production, iodine monochloride can be produced continuously.

〔Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 While gradually adding solid iodine to a 51 reactor equipped with a stirrer, dry chlorine was introduced to produce 6.35 kg of crude iodine monochloride.
I got it. Crude iodine monochloride existed as a liquid at 27-40°C. According to iodometric titration, the purity of iodine monochloride is 90.
．． It was 3%. While keeping this iodine monochloride at a temperature of 27 to 40°C, 1.56 kg of dried chlorine (22,0
mol) to create an excess chlorine state. The required amount of iodine, calculated from the excess amount of chlorine, was 5.08 kg (2
0,0mol) was charged into the reactor and stirred for 1 hour. Highly purified iodine monochloride with a purity of 99.8% was determined by iodometric titration.
．． I was able to get 0X. The loss of iodine and chlorine was less than 2%.

Example 2 Crude iodine monochloride 6.12K was prepared in the same manner as in Example 1.
I got g. According to iodometric titration, the purity of iodine monochloride is 74.0.
%Met. 1.79 chlorine dried to this crude iodine monochloride
Kg (25.2 mol) was introduced to create an excess chlorine state. As in Example 1, 5.08 kg of iodine (20,0+wo
1), 13.0 kg of iodine monochloride with a high purity of 99.7% was obtained. The loss of iodine and chlorine was less than 2%.

Example 3 High purity iodine monochloride 6.5K obtained in Example 2
g (40 mol) remained in reactor 51. When 1.42 kg (20 mol) of dried chlorine was introduced into this and 5.08 kg (20 mol) of iodine was added in the same manner as in Example 2, 13.00 kg of iodine monochloride with a purity of 99.7X could be obtained. . Furthermore, when 6.5% of iodine monochloride was left in the pot and the same operation was repeated 5 times, the purity was 99.6-9.
It was possible to obtain 9.9% iodine monochloride. The loss of iodine and chlorine when repeated five times was 2%.

〔Effect of the invention〕

According to the method of the present invention, there is almost no loss of chlorine (and the required amount of iodine can be calculated from the amount of chlorine introduced, so high purity iodine monochloride can be produced after adding iodine.

Further, distillation and other purification are not required, and the process can be simplified.

Patent applicant: Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1 Production of iodine monochloride consisting of gaseous chlorine and solid iodine, characterized in that after excess chlorine is absorbed into liquid iodine monochloride, solid iodine is added. Method.