Sinopec has newly obtained an invention patent for the “Reaction system and method for preparing 2,6-naphthalenedicarboxylic acid by oxidizing 2,6-diisopropynanaphthalene”

Commissioning of the ethylene glycol plant renovation project at Shanghai Petrochemical https://bbs.hcbbs.com/thread-5694567-1-1.html (Source: Haichuan Chemical Forum)

【Haichuan Teahouse】Bayannur is famous not only for its sunflowers but also for its watermelons. https://bbs.hcbbs.com/thread-5694667-1-1.html (Source: Haichuan Chemical Industry Forum)

【Haichuan Teahouse】In the rural areas of the north, what matters most at banquets is the lively atmosphere! ! ! ! https://bbs.hcbbs.com/thread-5694801-1-1.html (Source: Haichuan Chemical Industry Forum)

China began PEN research in the 1970s, mainly for insulating films; for example, the Guilin Electrical Apparatus Research Institute developed PEN films. In the 1980s, institutions such as China Textile University and Anshan Iron and Steel Institute conducted systematic research on the structural properties of PEN. Yizheng Chemical Fiber began developing PEN polymerization processes in 1996, but industrialization was not achieved. Since 2018, the Coal Science and Technology Research Institute has been working on the technology for synthesizing 2,6-NDA from coal. In November 2024, it established a pilot-scale production platform using microchannel reactors; the purity of the resulting product is ≥99.95%, and its performance is on par with that of imported products. During the same period, Guoneng Baotou Coal Chemical started a pilot project for the production of 2,6-NDA on a scale of 100 tons per year, utilizing coal tar as a raw material to reduce costs. In the same year, Liaoning Fine Chemicals collaborated with the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, to develop an integrated \"naphthylalkylation-oxidation\" process. This process enabled the mass production of polymer-grade 2,6-NDA using nanofiltration purification technology, and the results were rated as \"internationally advanced\". In recent years, PEN has found wide applications in various fields such as 5G film materials, flexible circuit boards, solar cell backplanes, sealing films for fuel cell membrane electrodes, and aerospace materials. At present, large international companies such as BP-Amoco in Europe and the United States, DuPont, M&G, Eastman, and Teijin in Japan have achieved industrial-scale production of PEN and have launched a range of PEN products. In 2024, the scale of the domestic PEN market was 27.06 billion yuan, and it is expected to rise to 45 billion yuan by 2029, with an average annual growth rate of 10.2%. At present, the industrial production of PEN in China has not been achieved; it represents a technical challenge that poses a bottleneck. As interest in PEN continues to grow, China is accelerating the industrialization of PEN and its monomers, and there is an urgent need to establish PEN production lines with independent intellectual property rights.

Production process: In terms of the production process, there are two methods for producing PEN: direct esterification and transesterification. The direct esterification method involves the polycondensation of 2,6-naphthalenedicarboxylic acid with ethylene glycol to form 2,6-naphthalenedicarboxylic acid ethyl ester (2,6-BHEN), under nitrogen atmosphere and in the presence of a magnesium acetate catalyst. Polymerization was carried out under nitrogen protection at 230°C for 4 hours, after which antimony trioxide was added; the temperature was then raised to 295°C to carry out polymerization under reduced pressure to obtain PEN. This method can be operated either intermittently or continuously, but it requires high purity of the raw material 2,6-naphthalic dicarboxylic acid (NDC), and the production technology is not yet mature, remaining in the experimental research stage. The transesterification method refers to a process in which, under nitrogen atmosphere, dimethyl 2,6-naphthoate reacts with ethylene glycol in the presence of composite metal salt catalysts such as magnesium acetate and antimony acetate; the reaction takes place at a temperature of 190°C, resulting in the formation of ethylenediamide 2,6-naphthoate (2,6-BHEN). Using antimony trioxide and similar substances as polycondensation catalysts, PEN is obtained by the polycondensation of 2,6-BHEN under high temperature (280–295°C) and high vacuum.

【Ten Years of Rapid Development in Chemical Engineering Equipment】From 2025 to 2025, the domestically developed additive PCA-BC for the efficient conversion of heavy oil was successfully applied industrially in Dalian Petrochemical’s 3.5 million tons per year catalytic cracking unit; relevant calibration work was carried out. https://bbs.hcbbs.com/thread-5694600-1-1.html (Source: Haichuan Chemical Industry Forum)

【Haichuan Teahouse】Traditional intangible cultural heritage delicacies from Nanchong, Sichuan: Snacks like Guokui paired with Liangfen https://bbs.hcbbs.com/thread-5695127-1-1.html (Source: Haichuan Chemical Industry Forum)