Method for preparing dialkyl ester percarbonate solution

A technology of dialkyl percarbonate and alkyl, which is applied in the field of preparing dialkyl percarbonate solution, can solve the problems of unallowable and unsolvable storage and instability of dialkyl percarbonate, and achieve The effect of improving reproducibility

Inactive Publication Date: 2006-08-02
SOLVAY SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the methods described in these two documents do not solve the problems associated with the instability of dialkyl peroxydicarbonates in storage, nor do they allow the automatic addition of initiators to the polymerization reactor and the delayed addition of these to the polymerization reactor. Initiator

Method used

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Examples

Experimental program
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Effect test

example 1

[0051] The following examples are intended to illustrate the invention. It involves the aqueous suspension homopolymerization of vinyl chloride using a solution containing about 30% by weight of dialkyl peroxydicarbonate in bis(ethylhexyl) adipate. The perdicarbonate is prepared by reacting ethyl chloroformate, hydrogen peroxide and sodium hydroxide, and then extracting with di(ethylhexyl) adipate.

[0052] Preparation of diethyl percarbonate

[0053] Add 622 kg of an aqueous solution containing 180 g / L sodium chloride (i.e. 510 kg of demineralized water and 112 kg of sodium chloride) to a 1000 liter reactor cooled to below 10°C and constantly stirred . Subsequently, 20.4 kg of ethyl chloroformate and 8.5 kg of an aqueous solution containing 350 g / kg hydrogen peroxide were successively added to the stirred aqueous solution, and finally, 36.1 liters of an aqueous solution containing 200 g / kg of sodium hydroxide were added very slowly. The temperature is maintained below 10°C...

example 2

[0057] Example 2 (comparative example)

[0058] As a comparison, under the same conditions as Example 1, the vinyl chloride polymerization was repeatedly carried out, but the difference was that at first an appropriate amount of diethyl peroxydicarbonate was synthesized in situ in the polymerization reactor as follows: Allow 0.734 kilograms of ethyl chloroformate and 0.109 kilograms of hydrogen peroxide to be used for polymerizing all quantity water (adding 0.284 kilograms of sodium hydroxide alkalized) and the whole quantity polyvinyl alcohol (referring to example 1: namely total 1860 1 kg of water and 1.335 kg of polyvinyl alcohol) in the presence of the reaction. After the initiator "in situ" synthesis was complete, the reactor was tightly capped, stirring was stopped and the reactor was kept under partial vacuum (60 mm Hg absolute pressure) for 5 minutes. 1,335 kg of vinyl chloride were added under stirring (110 rpm). Subsequently, heating and polymerization were carried...

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Abstract

The dialkyl peroxydicarbonates with short alkyl chains, are used for the aqueous suspension polymerization of vinyl chloride, in the form of a solution in a dialkyl alkanedicarboxylate. The preferred solvents are hexanedicarboxylates (adipates) derived from adipic acid and C6-C10 alkanols. The peroxydicarbonate concentration of the said solutions is generally 15-40% by weight. The process according to the invention produces vinyl chloride polymers of improved quality resulting in shaped articles exhibiting markedly fewer fisheyes. The invention also relates to a two-stage process for the manufacture of a solution of dialkyl peroxydicarbonates with short alkyl chains which is particularly suited for the aqueous suspension polymerization of vinyl chloride. According to this process an inorganic salt is used in the stage of manufacture of the peroxydicarbonate (first stage) and the latter is subsequently isolated by extraction by means of a water-insoluble solvent (second stage).

Description

[0001] The patent application for this invention is a divisional case of the PCT application with application number 97193272.7 (priority date: January 25, 1996 / BE) entering the Chinese national phase. technical field [0002] The present invention relates to a process for the preparation of dialkyl perdicarbonate solutions. More particularly, the present invention relates to a process for preparing short alkyl chain dialkyl perdicarbonate solutions, especially dialkyl perdicarbonate solutions in which the alkyl group contains 2 to 3 carbon atoms. Background technique [0003] The use of dialkyl peroxydicarbonates to initiate the aqueous suspension polymerization of vinyl chloride is known. Initiators composed of short alkyl chain dialkyl peroxydicarbonates, such as diethyl peroxydicarbonate and diisopropyl percarbonate, are particularly favored due to their high activity at the usual vinyl chloride polymerization temperatures. However, they have the disadvantage of being u...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F2/44C08F14/06C07C409/38C07C409/34C08FC08F2/18C08F4/28C08F4/34C08F4/36C08F14/00
CPCC07C407/00C08F14/06C07C407/003C08F2/18C07C409/32
Inventor V·波达特
Owner SOLVAY SA
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