DOTP Production Process
From Recycled PET to Premium Dioctyl Terephthalate (DOTP) Plasticizer
DOTP Manufacturing Process Flowchart
Our closed-loop production system transforms waste PET into high-value DOTP plasticizer while recovering byproducts for circular economy.
PET Sorting
Clean and sort recycled PET bottles, removing labels, caps, and other contaminants to ensure raw material purity.
Crushing
PET bottles are crushed into small flakes, increasing surface area for efficient chemical reactions in the next stage.
Feeding
Measured octanol and PET flakes are transferred into the pre-dissolution tank under vacuum with continuous stirring.
Esterification
Catalyst is added and transesterification occurs at controlled temperature, converting PET and octanol into crude DOTP ester.
Distillation
Crude ester is distilled under vacuum to separate DOTP from byproducts like ethylene glycol and excess octanol.
Neutralization
Crude DOTP is neutralized with sodium hydroxide solution and washed with water to remove residual acidity.
Alcohol Removal
Residual alcohol is removed under vacuum using steam stripping, then condensed and recovered for recycling.
Filtration
Diatomite is added as filter aid to remove fine impurities, producing pure DOTP ready for storage and delivery.
DOTP Product
High-purity DOTP plasticizer is transferred to finished product tanks, meeting ISO and SGS quality standards.
Clean and sort recycled PET bottles, removing labels, caps, and other contaminants to ensure raw material purity.
PET bottles are crushed into small flakes, increasing surface area for efficient chemical reactions in the next stage.
Measured octanol and PET flakes are transferred into the pre-dissolution tank under vacuum with continuous stirring.
Catalyst is added and transesterification occurs at controlled temperature, converting PET and octanol into crude DOTP ester.
Crude ester is distilled under vacuum to separate DOTP from byproducts like ethylene glycol and excess octanol.
Crude DOTP is neutralized with sodium hydroxide solution and washed with water to remove residual acidity.
Residual alcohol is removed under vacuum using steam stripping, then condensed and recovered for recycling.
Diatomite is added as filter aid to remove fine impurities, producing pure DOTP ready for storage and delivery.
High-purity DOTP plasticizer is transferred to finished product tanks, meeting ISO and SGS quality standards.
Octanol Recovery
Recovered octanol is refined through distillation and recycled back to the feeding stage, achieving closed-loop utilization and reducing raw material consumption.
Ethylene Glycol Recovery
Ethylene glycol generated during transesterification is purified to commercial grade through distillation and sold as MEG (monoethylene glycol), creating additional value from byproducts.
Quality Control & Certifications
ISO-certified, SGS-tested, consistently reliable
ISO Integrated Management System
Our DOTP production is certified to ISO 9001, ISO 14001, ISO 45001 and ISO 50001, covering quality, environment, occupational health and energy management.
SGS Third-Party Testing
Every batch is tested by SGS for phthalate compliance, EN 71-3 toy safety and PFAS screening, ensuring DOTP meets global regulatory standards.
Internationally Advanced Process
Our PET-to-DOTP transesterification process has been evaluated as internationally advanced, supported by more than 20 national patents.
8-Step DOTP Production Process from Recycled PET
2. Transesterification
The mixed material is pumped into the esterification reactor, heated, and catalyst is added for transesterification. Generated ethylene glycol and partial octanol vapor are condensed into the alcohol-water separator. Octanol returns to the reactor, while ethylene glycol aqueous solution goes to the distillation column.
3. Distillation
The crude ester from esterification enters the distillation kettle under negative pressure. Controlling vacuum and temperature, DOTP and octanol are distilled, condensed into the receiver, and non-condensable gases enter the vacuum system. Distillation residue is treated as hazardous waste.
4. Neutralization & Water Washing
The distilled DOTP crude ester contains acidity and requires neutralization. Material is transferred to the neutralization tank under vacuum, sodium hydroxide solution is added for neutralization, followed by water washing. Wastewater undergoes acid precipitation to recover organic acid, and sodium sulfate brine is treated by MVR evaporation.
5. Alcohol Removal
The neutralized and washed crude ester is transferred to the alcohol removal kettle under negative pressure. Temperature is raised and pressure reduced for alcohol removal. Steam stripping removes residual alcohol. The distilled octanol and water vapor are condensed into the recovered alcohol receiver.
6. Pressure Filtration
Diatomite is added as filter aid. The crude ester is filtered and pumped into the DOTP finished product storage tank. Filter residue is sent to the hazardous waste temporary storage room.
7. Recovered Alcohol Distillation
After settling and water separation, the alcohol layer is transferred to the recovered alcohol tank for distillation. The process includes alkali preparation, neutralization, octanone distillation, and octanol distillation. Distillation residue is handled by qualified disposal units.
8. Ethylene Glycol Distillation
The No.1 distillation column feeds under vacuum and heats to evaporate water, which is condensed and returned to the alcohol-water separator. When kettle temperature reaches the set point, continuous feeding and reflux ratio adjustment separate ethylene glycol. When content meets standard, it enters the ethylene glycol finished product tank.
Eco-Friendly & Sustainable Manufacturing
Turning waste PET into high-performance plasticizer
Waste PET Recycling
We source post-consumer and post-industrial PET flakes as feedstock, reducing landfill waste and replacing fossil-based raw materials in plasticizer production.
Closed-Loop Byproduct Recovery
More than 95% of recovered octanol is refined and reused. Ethylene glycol is purified to commercial grade, minimizing waste and raw material consumption.
Emission & Wastewater Control
Exhaust gas and process wastewater are treated before discharge. MVR evaporation reduces brine volume and recovers reusable salts and water.
Phthalate-Free Plasticizer
DOTP is a non-phthalate, eco-friendly plasticizer widely used in sensitive applications such as medical films, food packaging and children's toys.
DOTP Technical Specifications
| Parameter | Specification |
|---|---|
| Appearance | Transparent liquid |
| Density (g/cm³) | 0.980-0.985 |
| Content (%) | ≥98 |
| Color (APHA) | ≤150 |
| Acidity (as terephthalic acid) (%) | ≤0.035 |
| Volume Resistance (Ω·cm) | ≥2×10¹² |
| Flash point (°C) | ≥210 |
| Water Content (%) | ≤0.1 |
Frequently Asked Questions About DOTP Production
How is DOTP produced from recycled PET?
What are the raw materials for DOTP production?
Is the DOTP production process environmentally friendly?
What byproducts are recovered during DOTP manufacturing?
What quality standards does your DOTP meet?
How long does the DOTP production process take?
What is the difference between DOTP and DOP production?
Can DOTP be produced from 100% recycled PET?
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High-quality DOTP plasticizer from recycled PET. ISO-certified, SGS-tested, globally delivered. Explore our custom packaging options.
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