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Process for producing aromatic polycarbonate

An aromatic carbonate and polycarbonate technology, applied in the field of aromatic polycarbonate manufacturing, can solve the problem of accumulating by-product coloring impurities and coloring impurities

Active Publication Date: 2006-09-27
MITSUBISHI RAYON CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, if the mother liquor is completely recycled without treatment, the above-mentioned by-products, coloring impurities, and coloring impurities will accumulate

Method used

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  • Process for producing aromatic polycarbonate
  • Process for producing aromatic polycarbonate
  • Process for producing aromatic polycarbonate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0217] The present invention will be explained in more detail below with respect to s-PL processing.

[0218] (Manufacture of dehydrated s-PL)

[0219] [PC polymerization step]

[0220] In a nitrogen atmosphere, BPA (manufactured by Mitsubishi Chemical Co., Ltd.; BPA obtained in Reference Example 2 described later) supplied at 34.3 kg / hr (kilogram / hour) and BPA supplied at 33.5 kg / hr were melt-mixed at 130° C. DPC (manufactured by Mitsubishi Chemical Co., Ltd.; DPC obtained in Reference Example 1 described later). The mixture was continuously fed into the first vertical stirring polymerization tank adjusted to normal pressure, nitrogen atmosphere and 210°C through a raw material introduction pipe heated to 130°C. The liquid level was kept constant by adjusting the opening of the valve installed in the polymer discharge line connected to the bottom of the tank, resulting in an average residence time of 60 minutes. In addition, at the same time as the starting of the feed of ...

experiment example 1

[0234] (Experimental Example 1) Production of DPC

[0235] First, the following methods are explained in detail: Figure 5 The dehydrated s-PL discharged as a distillate from the second PL distillation column shown is used as a raw material for DPC to manufacture DPC, and at the same time, the PC low-boiling distillate ( D6) is recycled to the DPC wash step.

[0236] [DPC reaction step / dehydrochloric acid step]

[0237] according tofigure 1 The flow chart shown carries out the DPC fabrication steps. Incidentally, the DPC reactor 1 used consisted of two reactors connected in series.

[0238] Purified s-PL having a temperature of 50 °C in a molten state was continuously fed at 30.0 kg / hr (0.32 kmol / hr) to the DPC first reactor, while PL containing pyridine was added as a catalyst, the pyridine containing PL is obtained by dehydrating low boiling substances discharged as distillate from a low boiling substance distillation column described later. While thus feeding, the abov...

reference example 1

[0247] (Reference example 1) Manufacture of DPC

[0248] DPC was produced in the same manner as in Experimental Example 1, except that commercially available PL (manufactured by Mitsubishi Chemical Corporation) was used instead of purified s-PL.

[0249] [result]

[0250] It was determined that even when s-PL was used, the same yield as using commercially available PL was obtained and the manufacturing efficiency was maintained.

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Abstract

A subject for the invention relates to a method for coping with by-product phenol in which the water content of the by-product PL generated in a PC production step is limited to a value in a given range to thereby maintain a production efficiency in the BPA production step and DPC production step to which the by-product PL is sent, whereby the overall efficiency of PC production is maintained. The invention is a process for producing an aromatic polycarbonate which comprises a diphenyl carbonate production step, a bisphenol A production step, and an aromatic polycarbonate production step, and is characterized in that the amount of water contained in the by-product phenol recovered in the aromatic polycarbonate production step is regulated to 0.2% by weight or smaller and this phenol is used as a starting material in the diphenyl carbonate production step and / or the bisphenol A production step.

Description

technical field [0001] The present invention relates to a method for producing an aromatic polycarbonate. Background technique [0002] Aromatic carbonate (hereinafter abbreviated as "PC") is usually produced by polymerizing diphenyl carbonate (hereinafter abbreviated as "DPC") and bisphenol A (hereinafter abbreviated as "BPA"). [0003] [Treatment of by-product phenol] [0004] In the above-mentioned polymerization reaction, phenol (hereinafter abbreviated as "PL") is produced as a by-product. The by-product PL contains impurities such as DPC, BPA, and oligomers formed from one to several DPC molecules and one to several BPA molecules. Methods of returning the by-product PL to the BPA manufacturing step or the DPC manufacturing step are known. [0005] That is, Patent Document 1 describes a method in which the by-product PL is directly or purified to a low purity and then returned to the BPA production step. The reason for the low degree of purification of the obtained ...

Claims

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Application Information

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IPC IPC(8): C08G64/30
Inventor 兵头成俊田中竜郎早志功一
Owner MITSUBISHI RAYON CO LTD
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