Neorius | Advanced Refining and Chemical Technologies

Chlorinated Phthalic Anhydride Production Technology

Chlorinated phthalic anhydride is a key raw material for synthesizing many polyimide dianhydride monomers. It is also an ideal raw material for producing cost-efficient polyimides. By adopting an advanced chlorinated phthalic anhydride technology, the production cost can be significantly reduced. This provides the polyimide industry with high-quality and affordable raw materials and plays an important role in supporting the development of polyimide sector.

High-performance polymers are one of the three major pillars in the materials field. Among them, polyimides (PI) hold a prominent position. They are considered the best comprehensive high-performance polymers. Their key features include high-temperature resistance, low-temperature resistance, radiation resistance, chemical resistance, high strength, self-lubrication, structural stability, and excellent insulation properties. Polyimides are widely recognized as "problem-solving" materials.

Another important advantage of polyimides is their strong design flexibility. Different dianhydrides and diamines can be combined to produce polyimides with different properties. They can be manufactured into fibers, films, foams, resin pellets, and many other forms.

Working Principle:

This technology uses an advanced, mature, and reliable liquid-phase air oxidation process for chlorinated o-xylene. It is widely recognized as the most competitive production route for chlorinated phthalic anhydride.

The process uses o-xylene and chlorine as raw materials.

• First, o-xylene reacts with chlorine through continuous chlorination to produce chlorinated o-xylene.

• Then, the chlorinated o-xylene undergoes continuous liquid-phase air oxidation to form chlorinated phthalic anhydride.

Key Features & Benefits

High returns and low costs

The process builds on established batch chlorination and batch liquid-phase air oxidation methods. It integrates the latest advances in modern chemical engineering and safety requirements. The technological improvements result in:

• high automation,

• improved safety,

• higher production efficiency,

• lower material and energy consumption.

The continuous production process represents a major step forward in efficiency, reliability, and resource savings.

Experienced Technical Team

The project leader previously oversaw the construction of the world’s first 300-ton/year liquid-phase air oxidation plant for producing monochlorinated phthalic anhydride from chlorinated o-xylene. He also led the technical upgrades afterward. The team successfully solved many key engineering challenges and made a significant contribution to the world’s first industrial-scale production of monochlorinated phthalic anhydride.

Technical Specifications

There is no unified product quality standard for monochlorinated phthalic anhydride. Quality is defined according to user requirements and set as an enterprise standard. The product purity is measured using gas chromatography.

Applications

The unique molecular structure of monochlorinated phthalic anhydride gives it important application value in many fields. It is especially valuable in polyimide production. It is an ideal raw material for synthesizing high-performance dianhydride monomers such as:

• ODPA,

• HQDPA,

• TDPA,

• BPADA,

• BPDA.

Technologies using mixed chlorinated phthalic anhydrides to produce cost-efficient polyimides are already mature. For example:

• In PEI (polyetherimide) production, chlorinated phthalic anhydride can fully replace nitrophthalic anhydride, eliminating nitrite-related environmental issues.

• Low-cost poly(thioether imide) (PTEI) technologies based on chlorinated phthalic anhydride are also becoming mature.