JPS6097952A - Production of peroxydicarbonate - Google Patents

Abstract

PURPOSE:To obtain the titled compound in high yield, by reacting a chloroformate with hydrogen peroxide and an aqueous solution of an alkali metal hydroxide, separating the reaction product into liquid layers, and cooling and separating the organic layer composed mainly of a peroxydicarbonate. CONSTITUTION:One or more chloroformates of formula I (R is 2-10C alkyl or its alkoxy-substituted group) are made to react with hydrogen peroxide and an aqueous solution of an alkali metal hydroxide. The obtained reaction product is separated into liquid layers, and the organic layer composed mainly of the peroxydicarbonate of formula II (R1 and R2 are same as R) is separated. The organic layer is optionally washed with an aqueous solution of a neutral salt, cooled at -1--60 deg.C, preferably -15--25 deg.C, and the solidified water, by- products and unreacted raw materials are separated and removed to obtain the objective compound of formula III. EFFECT:The by-products and the unreacted raw materials can be removed efficiently. USE:A radical generator, or a polymerization initiator for vinyl monomers.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing peroxydicarbonate. More specifically, the present invention relates to a method for producing peroxydicarbonate that can efficiently and safely remove by-products and unreacted raw materials.

Peroxydicarbonate has the general formula, (In the formula, R is, for example, an aliphatic hydrocarbon copper group r-i".

). These compounds are important in the polymer industry as radical generators. In particular, they are important in the polymerization of vinyl monomers. In general, peroxydicarbonates are After treating the chloroformate with a mixed aqueous solution of hydrogen peroxide and an alkali metal hydroxide at about θ to 20'C, the resulting reaction product containing peroxydicarbonate as the main component is treated with a neutral salt aqueous solution. It is obtained by washing and separating.However, in this production method, when the separation is performed after washing, the speed is extremely slow or the separation is often incomplete.This means that the target product, peroxydicarbonate, is Because they are sensitive to heat and easily decompose, they pose important industrial problems in terms of product deterioration and safety.

Conventionally, in order to solve this problem, for example,
6-98705, after treating a solution containing two types of chloroformates with a mixed aqueous solution of hydrogen peroxide and potassium carbonate and potassium hydroxide at about 8'C,
A method of washing the obtained reaction product with an extremely highly concentrated aqueous sodium chloride solution (25%), and a method disclosed in JP-A-57-
Publication No. 98957 states that chloroformate is heated at about 80°C.
A method has been proposed in which the reaction product is continuously treated with a mixed aqueous solution of hydrogen peroxide, sodium hydroxide, and a wetting agent, and then the resulting reaction product is separated using a disk separator.

In the former method, the rate of separation of the organic layer and aqueous layer is extremely slow during cleaning to remove by-products and unreacted raw materials mixed in the reaction product, and it is desired that the organic layer and aqueous layer be separated even faster. It wasn't perfect, so I had to wash it many times. If an organic solvent is used in this case, the separation speed can be considerably increased, but a large amount of organic solvent must be used.

Furthermore, in the latter method, the target product, peroxydicarbonate, is sensitive to metals, heat, and alkaline aqueous solutions and easily decomposes, but the reaction product is handled under conditions that include these. This poses an important industrial problem in terms of safety and product deterioration.

Therefore, the present inventors conducted extensive research with the aim of providing a method for industrially producing peroxydicarbonate efficiently and safely. 8) Separate the reaction product obtained by the reaction with the aqueous solution,
The organic layer containing peroxydicarbonate as a main component is taken out, and the organic layer is left as it is or the washed organic layer obtained with a neutral salt aqueous solution is cooled to a temperature range of -1"C to -60°C. The present invention was completed based on the knowledge that water-soluble by-products and unreacted raw materials contained in the organic layer can be safely and quickly reduced by separating and removing the dispersed coagulated water. It's arrived.

The gist of the present invention is that the following general formula (■) is obtained by separating the reaction product obtained by the reaction of 10 roloformate, hydrogen peroxide, and an alkali metal hydroxide. (11) % Formula %() C In the formula, R, R□, and R8 represent a straight chain or branched alkyl group having 2 to 10 carbon atoms, or an alkoxy group-substituted product thereof. ) 2.( (4) Either the organic layer of the reaction product containing peroxydicarbonate as the main component (1) as it is or the washed organic layer obtained with a neutral salt aqueous solution at -1°C to -60°C. 5, which is characterized by cooling to a temperature range and separating and removing coagulated water dispersed in the organic layer.In this case, the purpose is to lower the coagulation temperature of peroxydicarbonate, to promote separation, etc. An organic solvent that is inert to the organic peroxide can be used.It can be added at any time, but
For example, when dropping chloroformate, add 1
Add 0. Further, the purification step can be carried out either batchwise or continuously.

The peroxydicarbonate obtained by the present invention is
It does not solidify in the cooling temperature range defined by the present invention, and includes all peroxydicarbonates represented by the above general formula (M) derived from chloroformate, which will be described later, and mixtures thereof. For example, diethyl peroxydicarbonate.

Diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, 2゜di-n-
Propyl peroxydicarbonate, 'G5ee-
Examples include butyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, dimethoxyisopropyl peroxydicarbonate, and the like.

Chloroformates used in the present invention include, for example, ethyl chloroformate, isopropyl chloroformate, 2-ethylhexyl chloroformate), n-7'ropyl chloroformate, SeQ-butyl chloroformate, Examples include -ethoxyethyl chloroformate, methoxyisopropyl chloroformate, 8-methoxybutyl chloroformate, and bromoformate in which chlorine is replaced with bromine.

The present invention employs hydrogen peroxide as a reactant,15 which is normally present in a stoichiometric amount of 0.
．． It is used in a range of 9 to 2.0 times. In addition, alkali metal hydroxides, such as potassium hydroxide and potassium hydroxide, are usually present in stoichiometric amounts of 0 to chloroformate.
．． It is used in the range of 9 to 2.0 times and is 2 degrees.

Conventional cooling means are used to cool the reaction product and solidify the water contained therein.

For example, a method of cooling from a jacket attached to the reaction vessel, and a method of cooling by charging solid carbon dioxide (dry ice) or liquid nitrogen 5 are shown. The temperature range for cooling varies depending on the reaction conditions and the type of peroxydicarbonate, but is usually -1°C to -60°C, preferably -10"C to -4°C.
0"C1 Most preferably, it is carried out at -15°C to -25°C. If the cooling temperature is too high, by-products and unreacted raw materials mixed in the organic layer cannot be sufficiently removed; on the other hand, if the cooling temperature is too low, the cooling temperature is too low. The viscosity of the oil phase increases, making it difficult to handle.

As a method for separating and removing the coagulated water dispersed in the organic layer, any of the usual means for separating solids and liquids can be used. For example, natural filtration and suction filtration methods using P paper, P cloth or wire mesh, and centrifugal filtration machines that continuously separate solids and liquids can also be used.

Neutral for cleaning peroxydicarbonate! -) For the aqueous salt solution, a metal salt whose aqueous solution is neutral, such as sodium chloride, potassium chloride, sodium sulfate, magnesium sulfate, etc., is used. Although its concentration is not particularly limited, it is usually used at 10% by weight or less.

As the organic solvent, peroxydicarbonate containing an organic solvent does not solidify in the cooling temperature range limited in the present invention,
Those inert to peroxydicarbonate are used. According to the present invention, even organic solvents with low boiling points can be used safely. This is because the peroxydicarbonate purification method of the present invention requires fewer washings and requires less time for purification than conventional methods.

Examples of organic solvents include mineral spirits,
Toluene, xylene, cyclohexane, dioctyl adipate, dibutyl phthalate, diethyl phthalate, diethyl ether, etc. can be used.

According to the present invention, thermally unstable peroxydicarbonates can be treated at low temperatures, making the treatment extremely safe.Also, the number of washings can be significantly reduced, so peroxydicarbonates can be treated at high temperatures. It can be produced with high yield.

The peroxydicarbonate obtained in the present invention is also useful as a polymerization initiator for vinyl monomers, particularly as an initiator for the sole or copolymerization of vinyl chloride monomers, which is polymerized at relatively low temperatures. For that purpose, the peroxydicarbonate obtained in the present invention is used as a diluted solution in an organic solvent, or it is used after being made into an aqueous emulsion using a surfactant, a dispersant, etc. For example, 0.1-20% by weight of nonionic surfactant and/or 0-10% by weight of the system or fully saponified polyvinyl acetate and 0-2% by weight of the system.
Compositions containing 0% by weight of antifreeze and +5 to 70% by weight of peroxydicarbonate and water relative to the system.

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

Example 1 A reactor with stirrer, arm plate, temperature needle and jacket was charged with 800 g of water and 170 g of 50% aqueous sodium hydroxide solution. Adjust the temperature of this reaction mixture to 0-5°C.
while maintaining? A 550% aqueous solution of 5II in hydrogen peroxide was added. The reaction mixture was cooled to about 10°C and
Addition of 85.9 g of 2-ethylhexyl chloroformate was started. The chloroformate was added over approximately 10 minutes. During the addition, the temperature rose to approximately zθ°C. After the addition, the temperature of the reaction mixture was reduced to 10°C while
Stirring was continued for 0 minutes. Thereafter, the oil layer was taken out from the resulting reaction product consisting of an aqueous layer and an oil layer. Next, it was washed with 400 g of a 1.0% by weight aqueous sodium sulfate solution. The obtained washed oil layer was separated and roughly separated from the water.
Cooled with brine to °C. Next, the oil layer was filtered to remove coagulated water. A portion of the organic layer thus obtained was taken and washed with an equal amount of water, and the pH value of the waste water was measured, and it showed a neutral value. On the other hand, it was found that the organic layer, which is mostly 2°, contained almost no water. In this way, di-2-ethylhexyl peroxydicarbonate was produced in a high yield of 8181 (yield: 90%).
%).

Comparative Example 1 The washed oil layer obtained by the method of Example 1 (the oil layer taken out from the reaction product was washed with 400 g of a 1.0% by weight aqueous sodium sulfate solution) was washed with 400 g of water at o'c. Separated by standing. The pH value of the wastewater is 1O15, and water washing and t.

The static separation was repeated four times. The pH value of the wastewater was alkaline and approximately 8.5 even after the fifth test, and the separation of by-products and unreacted raw materials was poor in all tests. Yield is also 70
% was low. In addition, an attempt was made to cool the washed oil layer obtained by the method of Example 1 with brine to -90°C and then filter out the coagulated water using a filter, but it took a long time because of the high viscosity.

Example 2 In Example 1, instead of 8851 2-ethylhexyl chloroformate, 278.9 8ec2° (11
) Using monobutyl chloroformate, the oil layer was heated to -151°C.
Instead, the procedure was carried out according to Example 1 except for cooling to -50°C with brine, and 210.9 of di-5ec-butyl peroxydicarbonate was obtained safely and in high yield (yield 89%). It was done. After that, the mixture was dehydrated using anhydrous sodium sulfate and filtered, but the process was performed safely with almost no heat generation.

Example 8 Instead of 885 g of 2-ethylhexyl chloroformate in Example 1, 1306. ! Example 1 was followed except that i' of methIOoxyisopropyl chloroformate and 100I of toluene were used and the oil layer was cooled with brine to -5°C instead of -15°C. In addition, 847 g of a toluene solution of dimethoxyisopropyl pen+5-ruoxydicarbonate was obtained with a high yield (90% yield).

Example 81115 in Example 1 of the meeting. ? Instead of 2-ethylhexyl chloroformate, 2-2° (1
B) Ethylhexylchloroformate and 8 of 151.9
The procedure of Example 1 was followed except that methoxybutyl chloroformate and 100.9 mineral spirit were used, and a high yield was achieved safely.
An asymmetric peroxydicarbonate-containing composition was obtained with p).

Reference Example 1 48% by weight of water, 12% by weight of methyl alcohol, 11% of 1B of polyvinyl alcohol, 1.5% by weight of Sorbi 1 (tan monolaurate and 1.5% by weight) were added to a reaction vessel equipped with a stirrer and a thermometer. 5% by weight of sorbitan monooleate was added, and 40% by weight of di-2-ethylhexyl peroxydicarbonate obtained in Example 1 was added dropwise with stirring. Stirring was continued for 60 minutes after the dropwise addition. As a result, a homogeneous milky white emulsion having a viscosity of 400 centivoids at 0° C. was obtained.

Reference Example 2 Suspension polymerization of vinyl chloride was carried out using 2° of di-2-ethylhexyl peroxydicarbonate obtained in Example 1 as a polymerization initiator. That is, 100 g of an aqueous solution in which 169 polyvinyl alcohol was dissolved in an 800 d stainless steel autoclave KO was added, and 5011, a vinyl chloride monomer, and 50.015.9 of the above-mentioned beluoxy-sidicarbonate were also added. The polymerization was carried out at 58±1° C. for 8 hours in a rotary thermostat. Thereafter, the polyvinyl chloride powder taken out was washed with water, filtered, and then vacuum dried. When the weight was determined to be 111, the polymerization conversion rate was about 85%. 1G Patent applicant NOF Corporation (15) -U00

Claims (1)

[Scope of Claims] L A reaction product obtained by the reaction of a chloroformate with tlP of 1 or more represented by the following general formula (Il, hydrogen peroxide, and an aqueous alkali metal hydroxide solution) is separated to form the following general formula: Take out the organic layer containing peroxydicarbonate represented by formula (1) as a main component, and wash the organic layer as it is or wash the organic layer obtained with a neutral 11 salt aqueous solution at a temperature range of -1'C to -60°C. A method for producing peroxydicarbonate, which is characterized by cooling the organic layer to a temperature of 100% and separating and removing solidified water, by-products, and unreacted raw materials dispersed in the organic layer.R-0-0-ai (I) 0 formula In the formula, R, R□, and R8 are straight, single-chain or branched alkyl groups having 2 to 10 carbon atoms, or alkyl groups thereof.) ? In claim 1, when cleaning an organic layer containing peroxydicarbonate as a main component, an organic solvent that is inert to peroxydicarbonate and does not solidify in the step of cooling the organic layer is included. A method for producing peroxydicarbonate, which comprises: