Molecular Formula | C10H10O4 |
Molar Mass | 194.18 |
Density | 1,29 g/cm3 |
Melting Point | 140 °C |
Boling Point | 288 °C |
Flash Point | 154 °C |
Water Solubility | It is slightly soluble in water but soluble in hot alcohol and ether. |
Solubility | Soluble in hot ethanol, methanol, ether, chloroform, insoluble in water. |
Vapor Presure | 1.15 mm Hg ( 93 °C) |
Vapor Density | 1.04 (vs air) |
Appearance | White crystal |
Color | White |
Merck | 14,9162 |
BRN | 1107185 |
pKa | 0[at 20 ℃] |
Storage Condition | Store below +30°C. |
Stability | Stable. Incompatible with strong acids, strong bases, strong oxidizing agents. |
Explosive Limit | 0.8-11.8%(V) |
Refractive Index | 1.4752 |
MDL | MFCD00008440 |
Physical and Chemical Properties | Property: colorless orthorhombic crystal system. |
Use | Mainly used for synthetic polyester fiber, resin, film, polyester paint and engineering plastics |
Risk Codes | 36/37/38 - Irritating to eyes, respiratory system and skin. |
Safety Description | 24/25 - Avoid contact with skin and eyes. |
UN IDs | 3256 |
WGK Germany | 1 |
RTECS | WZ1225000 |
TSCA | Yes |
HS Code | 2917 37 00 |
Toxicity | LD50 orally in Rabbit: 3200 mg/kg |
Reference Show more | 1. [IF=7.514] Nan Zhang et al."Hydrophilic carboxyl supported immobilization of UiO-66 for novel bar sorptive extraction of non-steroidal anti-inflammatory drugs in food samples."Food Chem. 2021 Sep;355:129623 |
A colorless orthorhombic crystal system. Melting point 140.6 °c. The relative density of liquid was 1. 084. Boiling point 283 °c. Heat to 230 °c is sublimation. Refractive index 4752. Viscosity (150 °c) o.965mPa -s. Ignition point 155 °c. Insoluble in water, soluble in ether and hot ethanol.
The basic process route is the esterification of terephthalic acid and methanol catalyzed by sulfuric acid or other catalysts. Specific intermittent, continuous, atmospheric pressure, pressure and other different process methods. The more advanced process is continuous combining oxidation with esterification (Wilton method) with p-xylene and
Methyl p-methylbenzoate was used as raw material, and cobalt and manganese metal salts were used as catalyst for pressure oxidation, followed by continuous esterification with methanol to obtain dimethyl terephthalate.
an intermediate of the polyester resin. Also used in the production of insulating paint, adhesive. It can also be used to produce a plasticizer, dioctyl terephthalate.
LogP | 2.25 at 25℃ |
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
application | mainly used for synthetic polyester fiber, resin, film, polyester paint and engineering plastics etc. dimethyl terephthalate is mainly used for manufacturing polyester resin, and then manufacturing films and fibers, as well as high-strength polyester insulating paint. Polyester film is mainly used as electrical insulation materials and film production (such as as film, X-ray film, photographic film and audio tape, video tape, electronic computer tape, etc.). The most common use of polyester resin is to make fibers, which are used in fabrics, fishing nets, carpets, tire cords, etc. It can also be used to produce the plasticizer dioctyl terephthalate. |
production method | obtained by esterification of terephthalic acid and methanol. Sulfuric acid catalyst was first used, the reaction temperature was 65-100 ℃, and the esterification time was 10-16h. With this method, the consumption of methanol is large and the production capacity is low. When the reaction pressure is increased and esterified at 0.39-0.49MPa, the reaction time can be shortened to 1-2h, and the loss of methanol is also reduced compared with the normal pressure method. In recent years, high temperature and high pressure liquid phase esterification method has been adopted. The reaction temperature is 250-300 ℃, and the pressure is 2-2.5MPa. Tin, zinc, and antimonide can be used as catalysts, or no catalyst can be used. The yield of terephthalic acid can reach 96-98% or higher. Another method of producing DMT is manufactured by the Witton-Heglis (Witten-Hercules) method, that is, the method of segmented oxidation and esterification of p-xylene is used. This method is in the oxidation process of two methyl groups of p-xylene., The carboxyl group oxidized first is methyl esterified to avoid side reactions in the next oxidation. In order to simplify the process, the two-step oxidation can be combined in one oxidation reactor, and the two-step esterification can also be combined in one esterification reactor. The raw material p-xylene and the circulating methyl p-methylbenzoate are simultaneously oxidized in a tower reactor at a reaction temperature of 140-170 ℃ and a pressure of 0.4-0.7MPa. Cobalt salt or cobalt and manganese salt are used as catalysts and continuously oxidized with air to generate p-methylbenzoic acid and monomethyl terephthalate. The oxidation product undergoes esterification reaction with excess methanol at 200-280 ℃, 2-2.5MPa. Methanol is distilled from the top of the esterification reactor and recycled after distillation; the crude ester from the bottom of the esterification reactor is distilled to separate methyl p-methylbenzoate (recycled to the oxidation reactor) and crude dimethyl terephthalate. In the dissolver, the crude dimethyl terephthalate is dissolved with methanol, and then sent to the crystallizer for precipitation and crystallization, centrifugation, and the obtained dimethyl terephthalate is distilled and purified to obtain a fiber-grade product with a purity of ≥ 99.9%. Raw material consumption quota: 630kg/t p-xylene and 440kg/t methanol. In the industrial production of dimethyl terephthalate, the segmented oxidation esterification of p-xylene has developed rapidly. This method does not use solvents when performing oxidation reactions, and the reactor does not need titanium materials. The product is easy to purify, so it has been adopted by many countries since the 1950s. The disadvantage is that the total yield of p-xylene is low (87%). |
category | flammable liquid |
toxicity classification | poisoning |
acute toxicity | oral-rat LD50: >3200 mg/kg |
stimulation data | eye-rabbit 500 mg/24 hours mild |
explosive hazard characteristics | blastable when mixed with air |
flammability hazard characteristics | combustible in case of open flame, high temperature and strong oxidant; Combustion emission stimulates smoke |
storage and transportation characteristics | complete packaging, light and light; warehouse ventilation, away from open flames, high temperature, separate storage from oxidant |
fire extinguishing agent | foam, carbon dioxide, dry powder, sand, mist water |
occupational standard | STEL 0.1 mg/m3 |
spontaneous combustion temperature | 520°C DIN 51794 |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |