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Method for preserving cyclic condensed formol

A cyclic formal and formaldehyde technology, which is used in indoor sanitary piping installations, waterway systems, drainage structures, etc.

Inactive Publication Date: 2004-09-22
MITSUBISHI GAS CHEM CO INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In addition, it is disclosed that at least one hindered phenol having a molecular weight of at least 350 is added to the group selected from 1,3-dioxolane, 1,3-dioxane, 1, the method in the cyclic formal of 1,4-butanediol formal, diethylene glycol formal and 1,3,5-trioxepane (trioxepane), but this method needs further improvement (referring to patent publication 4 )

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0036]

[0037] The preparation method of the present invention is a method of preparing a polyoxymethylene copolymer by copolymerization of cyclic formal and trioxane, in which, by adding 5-10,000 ppm phenol to a cyclic formal containing 5 ppm or less peroxide The cyclic formal obtained in the process.

[0038] As mentioned above, the cyclic formal in this preparation method is preferably derived from formaldehyde and an aliphatic diol containing 2 to 4 carbon atoms. The cyclic formal is as described above, and 1,3-dioxolane is particularly preferred.

[0039] Phenol is preferably added in an amount of 10-2,000 ppm, more preferably 10-1,000 ppm.

[0040]The preparation method of the present invention is characterized in that 5-10,000 ppm of phenol is added to the cyclic formal with a low content of peroxide before the cyclic formal is preserved, and the generation of the peroxide is suppressed in the cyclic formal Used as starting material. That is, the present invention uses cy...

Embodiment 1

[0088] The cyclic formal 1,3-dioxolane (product of Tokyo Kasei kogyo Co., Ltd.) used in the preservation test was purified by distillation before being used. The content of water and peroxide in 1,3-dioxolane obtained immediately after distillation were 5 ppm and 2 ppm, respectively. 100 g of purified 1,3-dioxolane was charged into a 200-ml Erlenmeyer flask, and phenol was added in an amount of 30 ppm based on 1,3-dioxolane. Then, the atmosphere in the system was replaced with nitrogen, and then the plug was sealed and allowed to stand at 60°C. After 10 days, the peroxide content in 1,3-dioxolane was 8 ppm, and after 20 days, the peroxide content in 1,3-dioxolane was 15 ppm.

Embodiment 2-4

[0090] Repeat the method of Example 1, except that the amount of phenol added is shown in Table 1. The results are shown in Table 1.

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PUM

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Abstract

A method for preserving cyclic formal is provided, thereby preserving monomer having improved thermostability for production of polyoxymethylene copolymer without reduction of quality. The method for preserving cyclic formal comprises adding 5 to 10,000 ppm, preferably 10 to 2,000 ppm of phenol into cyclic formal, wherein the cyclic formal comprises 5 ppm or less of peroxides; the cyclic formal is derived from formaldehyde and C2-C4 aliphatic diol; the cyclic formal is 1,3-dioxolane. The method for preparing polyoxymethylene copolymer comprises copolymerization of 0.5 to 40 mol% of cyclic formal and trioxane.

Description

Technical field [0001] The present invention relates to a method of preserving cyclic formal. The present invention also relates to a cyclic formal composition suitable for this preservation method. In addition, the present invention relates to a method for preparing a polyoxymethylene copolymer using the cyclic formal deposited in the present invention. Background technique [0002] In some cases, polyoxymethylene copolymers prepared from cyclic oligomers such as trioxane or tetraoxane and long-term preserved cyclic formal may not have satisfactory thermal stability. The cyclic formal may be used Cationic active catalyst and oligomer copolymerization. [0003] It is well known that the cause of the decrease in thermal stability is the peroxide derivative contained in the cyclic formal. Although it exists in a small amount, even at room temperature, the cyclic formal will still decompose, especially when it is exposed to a temperature of tens of degrees (℃) to 100℃ or higher, its...

Claims

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Application Information

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IPC IPC(8): C07D317/12C07D319/06C07D321/06
CPCE03C1/264E03F5/14
Inventor 须长大辅中谷大吾古川昌典中岛正之
Owner MITSUBISHI GAS CHEM CO INC
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