Application of dioctyl terephthalate_Kain Industrial Additive

Overview^[1][2]

Dioctyl terephthalate (DOTP) is an excellent main plasticizer used in polyvinyl chloride (PVC) plastics. Compared with the currently commonly used diisooctyl phthalate (DOP), it has the advantages of heat resistance, cold resistance, non-volatility, extraction resistance, softness and good electrical insulation properties, and shows excellent durability in products. , Soap water resistance and low temperature softness. Because of its low volatility, the use of DOTP can fully meet the temperature resistance requirements of wires and cables, and can be widely used in 70°C resistant cable materials (International Electrotechnical Commission IEC standard) and other various PVC soft products.

In addition to being widely used as a plasticizer for cable materials and PVC, DOTP can also be used in the production of artificial leather films. In addition, DOTP has excellent compatibility and can also be used as a plasticizer for acrylonitrile derivatives, polyvinyl butyral, nitrile rubber, nitrocellulose, etc. It can also be used as a plasticizer for synthetic rubber, coating additives, Precision instrument lubricant, lubricant additive, and can also be used as a paper softener.

Preparation method^[1-2]

Report 1,

A method for separating dioctyl terephthalate, specifically the following steps:

(1) Treatment during preparation of dioctyl terephthalate

Place terephthalic acid and isooctyl alcohol in a reaction kettle at a molar ratio of 1:3, raise the temperature to 180°C, stir continuously during this period, then add the catalyst, continue to raise the temperature, keep it warm at 205°C, and increase the stirring speed. , stir quickly at 300r/min for 15 minutes, which will help the catalyst to be fully dispersed in the raw materials to ensure a sufficient reaction. At the same time, accelerated stirring will quickly heat up the catalyst and avoid hydrolysis of the organic titanium catalyst during the slow heating process;

(2) Neutralization and dealcoholization treatment

Add the prepared dioctyl terephthalate semi-finished product to an alkaline decolorizing agent with a mass fraction of 0.5% terephthalic acid, and then distill isooctyl alcohol under reduced pressure. After the dealcoholization is completed, continue the heat preservation treatment at 205°C for 15 minutes, secondary decompression dealcoholization;

(3)Filtering

Filter the dealcoholized material while hot to obtain material A. Cool the material A to 150°C and filter twice to obtain material B. Cool the material B to 100°C and filter three times to obtain material C; then cool the material C to room temperature and filter it four times to complete the treatment and obtain the finished product dioctyl terephthalate.

Report 2,

Method for preparing dioctyl terephthalate through alcoholysis and esterification of polyester waste:

S1. Rinse the polyester waste, place it in an oven to dry at 100°C for 8 hours, and crush it into small particles with a crusher; the crusher is equipped with a dust removal device for environmentally friendly production;

S2. Weigh 100g of polyester waste particles and 170g of isooctyl alcohol in S1 and add them to the esterification kettle. The pressure is normal pressure. After first raising the temperature to 180°C, add 0.12g tetrabutyl titanate and raise the temperature to 225°C again. ℃, keep the temperature at about 225℃ to generate dioctyl terephthalate and ethylene glycol; ethylene glycol azeotropes with excess isooctyl alcohol, enters the esterification condenser for condensation, and is cooled by the condenser before entering the alcohol washing tank. , the interface level of the alcohol washing tank no longer rises, the reaction is deemed to be completed, and the reaction time is 15h;

S3. Pour the ethylene glycol aqueous solution into the alcohol extraction tower to extract alcohol under normal pressure. The alcohol extraction temperature is 180°C. After most of the water is evaporated through the condenser, it is pumped into the water tank for recycling to obtain no by-products. Color ethylene glycol.

To extract alcohol from the crude product, lower the temperature of the esterification kettle, turn on the vacuum pump to evacuate the alcohol extraction kettle (-0.1MPa), and suck the material into the alcohol extraction kettle. Under vacuum conditions, first use sensible heat and then use thermal oil to control The temperature of the alcohol extraction kettle is 180°C, and the isooctyl alcohol in the crude product is extracted. The isooctyl alcohol is condensed by the alcohol extraction condenser and then returned to the circulating alcohol tank for recycling. The crude product after alcohol extraction is put into the neutralization kettle for refinement.

S4. After the ethanol extraction, the crude product is introduced into the neutralization kettle and the thermal oil is turned on to control the material temperature to about 90°C. It is stirred and mixed with the metered 30% NaOH solution to cause a neutralization reaction. After the reaction is completed, the kettle temperature rises to 170°C. , turn on the vacuum pump to evacuate the neutralization kettle system, introduce low-pressure steam into the neutralization kettle under vacuum conditions (-0.1MPa), take the moisture and isooctyl alcohol contained in the material out of the neutralization kettle, and cool it through the condenser Then it is poured into the alcohol washing tank; isooctyl alcohol is separated from water in the alcohol washing tank, and isooctyl alcohol is reused as a raw material to continue to participate in the reaction; the refining time is about 3 hours;

S5. After dehydration, the material is cooled and poured into the filter kettle. Add a certain amount of activated carbon and stir for a period of time. Turn on the filter pump and drive the material into the plate and frame filter press to filter out the activated carbon and floc. The filtrate is cooled After cooling down, it enters the Japanese product tank, which is the finished product dioctyl terephthalate. In the end, the polyester waste was completely degraded, and the yield of dioctyl terephthalate reached 97.6% and the purity was 99%; the ethylene glycol yield was 96.3%.

Apply^[3]

CN201510403847.9 discloses a halogen-free flame-retardant TPVC material and a preparation method thereof. The halogen-free flame-retardant TPVC material is made of the following components by weight: 100 parts of PVC resin, 50~ plasticizer 100 parts, heat stabilizer 5~10 parts, lubricant 2~4 parts and halogen-free flame retardant 40~100 parts; plasticizer consists of dioctyl terephthalate, epoxy fatty acid methyl ester, diphenyl phosphate Isooctyl ester and chlorinated paraffin are composed according to the weight ratio of 100: (10~20): (100~50): (5~15); the halogen-free flame retardant is composed of active magnesium hydroxide, microencapsulated red phosphorus, trioxide Antimony and zinc borate are as follows: 100: (10~20): (5~15): (5~15) weight ratio composition. The halogen-free flame-retardant TPVC material of the present invention has good flame-retardant properties and mechanical properties, and is a green and environmentally friendly material that is harmless to the human body and the environment.

Main reference materials

[1] [Chinese invention] CN201710358843.2 A method for separating dioctyl terephthalate

[2] [Chinese invention] CN201910232161.6 A method for preparing dioctyl terephthalate through alcoholysis and esterification of polyester waste

[3] CN201510403847.9 Halogen-free flame retardant TPVC material and preparation method thereof