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Press Release

Demonstration of validation plant for DRC process to produce DPC, a monomer of PC

― An energy-saving production process with low carbon emissions and a safe feedstock ―
August  7,2017
New Energy and Industrial Technology Development Organization (NEDO)
Asahi Kasei Corp.

As part of a project of Japan's New Energy and Industrial Technology Development Organization (NEDO), Asahi Kasei Corp. verified at its Mizushima Works (Kurashiki, Okayama, Japan) a newly developed process for creating diphenyl carbonate (DPC) via dialkyl carbonate (DRC). DPC is a monomer used to produce polycarbonate (PC), which is used to make parts for vehicles, home appliances, and other items. The stability and operability of the process was confirmed through over 1,000 hours of continuous operation. The new process successfully reduces energy consumption and CO2 emission compared to the conventional process, while using CO2 as a safe feedstock.

Asahi Kasei will continue to verify the economy and energy efficiency of the new process, and work toward its further optimization as a highly energy-efficient process that utilizes CO2.

1. Overview

NEDO is an organization that supports the development of technology that is expected to have a strong energy-saving impact, mainly emphasizing technology classified as "important technology" in the Energy Efficiency Technology Strategy.

PC is a resin that is widely used in headlamp covers, personal computer housings, CDs, DVDs, and other products. Interfacial polymerization*1, which uses highly toxic phosgene, is the conventional process used to produce PC. The conventional process not only raises safety issues, but also presents the problem of its high energy consumption. As part of a NEDO project*2, in 2015, Asahi Kasei began construction of a validation plant at its Mizushima Works to verify its newly developed process for overcoming these issues by producing DPC via DRC ("DRC Production Process for DPC"). The technique’s stability and operability as an industrial process was also confirmed through over 1,000 hours of continuous operation. Asahi Kasei has successfully established the non-phosgene process using CO2 as a safe feedstock, enabling not only reduced energy consumption but also reduced CO2 emissions.

Asahi Kasei will continue to verify the economy and energy efficiency of the new process, and work toward its further optimization. Specifically, the company aims to achieve commercialization of the new highly energy-efficient process, which uses CO2 and reduces energy consumption through improved yield, and to establish technology for stable production by optimizing operating conditions and equipment. Validation of the new process will strengthen the licensing business Asahi Kasei established with its previously developed non-phosgene process for PC*3, which is used around the world, including in China, Korea, Taiwan, Russia, and Saudi Arabia.

<Outline of the validation plant>

Project period:
Fiscal years 2014–2016
DPC capacity:
1,000 tons/year
Location:
Asahi Kasei Corp. Mizushima Works (Kurashiki, Okayama, Japan)

2. Results of the validation

The DRC process for DPC utilizes technology which was developed by Asahi Kasei with the support of a NEDO project.*4 The technology uses catalysts to obtain DRC from CO2 and alcohol, and then obtains DPC from DRC and phenol. The feasibility of the DRC process for DPC has been validated through continuous operation to assess catalyst cycling and catalytic performance, in both the DRC step, which produces DRC from CO2 and alcohol, and the DPC step, which produces DPC from DRC and phenol. The reactor performance and the system for recycling unreacted feedstocks were also validated. A flowchart is shown below.

  • Gaphic illustration of DRC
    Figure 1: Flowchart of non-phosgene PC process with the DRC process for DPC

  1. Confirm stability and operability as an industrial process through over 1,000 hours of continuous operation.
  2. Achieve reduced energy consumption and CO2 emission compared with the conventional process for PC.
  3. Establish a production process using CO2 as a safe feedstock instead of highly toxic phosgene. The carbonyl group of polycarbonate is obtained from CO2, rather than from phosgene as in the conventional process.

  • Gaphic illustration of carbonyl group for polycarbonate
    Figure 2: Comparison between sources of carbonyl group for polycarbonate

【Glossary】

*1 Interfacial polymerization
Method of polymerization of bisphenol-A and phosgene in two phases of organic phase and aqueous phase.
*2 NEDO project
Program for Strategic Innovative Energy Saving Technology (2014–2016): Development of process to manufacture chemicals using CO2.
*3 Non-phosgene process for PC
A process to produce PC using DPC instead of highly toxic phosgene. The process applies melt polymerization of bisphenol-A and DPC.
*4 NEDO project
Innovation Promotion Program (2010): Development of catalysts having high catalytic activity and high stability.

3. For more information, please contact:

NEDO Energy Conservation Technology Department
Contact Person: Futagami Tel: +81-44-520-5281­

Asahi Kasei Corp. Corporate Communications
Tel: +81-3-3296-3008­