Structural formula
| Business number | 02Y5 |
|---|---|
| Molecular formula | C7H8 |
| Molecular weight | 92.14 |
| label |
Methylbenzene, Methacide, Phenylmethane, Dehydrating solvents for organic synthesis, Cleaning agents for the electronics industry, High octane gasoline additives, Aromatic hydrocarbon solvents |
Numbering system
CAS number:108-88-3
MDL number:MFCD00008512
EINECS number:203-625-9
RTECS number:XS5250000
BRN number:635760
PubChem number:24854682
Physical property data
1. Properties: colorless and transparent liquid with an aromatic odor similar to benzene. [1]
2. Melting point (℃): -94.9[2]
3. Boiling point (℃): 110.6[3]
4. Relative density (water = 1): 0.87[4]
5. Relative vapor Density (air=1): 3.14[5]
6. Saturated vapor pressure (kPa): 3.8 (25℃)[6]
7. Heat of combustion (kJ/mol): -3910.3[7]
8. Critical temperature (℃): 318.6[8]
9. Critical pressure (MPa): 4.11[9]
10. Octanol/water partition coefficient: 2.73 [10]
11. Flash point (℃): 4 (CC); 16 (OC) [11]
12. Ignition temperature (℃): 480[12]
13. Explosion limit (%): 7.1[13]
14. Lower explosion limit (%): 1.1[14]
15. Solubility: insoluble in water, miscible in most organic compounds such as benzene, ethanol, ether, and chloroform Solvent. [15]
16. Viscosity (mPa·s, 0ºC): 0.773
17. Viscosity (mPa·s, 20ºC): 0.5866
18. Flash point (ºC, closed): 4.4
19. Flash point (ºC, open): 7.2
20. Heat of vaporization (KJ/mol, 25ºC): 38.01
21. Heat of evaporation (KJ/mol, b.p.): 33.49
22. Heat of fusion (KJ/mol): 6.624
23 . Heat of formation (KJ/mol, gas): 50.032
24. Heat of formation (KJ/mol, liquid): 12.004
25. Specific heat capacity (KJ/(kg·K) , 25ºC, constant pressure): 1.1266
26. Boiling point rising constant: 3.33
27. Conductivity (S/m): 1.4×10-14
28. Thermal conductivity Kt =K20[1+α(t -20)],α=-1.44×10-3（W/(m·K)）：0.3823×10-3
29. Volume expansion coefficient (K-1,10~30ºC): 0.00107
30. Critical density (g·cm-3): 0.292
31. Critical volume (cm 3·mol-1): 316
32. Critical compression factor: 0.264
33. Eccentricity factor: 0.264
34. Lennard-Jones parameter (A): 5.9706
35. Lennard-Jones parameter (K): 379.83
36. Solubility parameter (J· cm-3)0.5: 18.346
37. van der Waals area (cm2·mol– 1): 7.42×109
38. van der Waals volume (cm3·mol-1): 59.510
39. Gas phase standard combustion heat (�Number of �centers: 0
12. Uncertain number of stereocenters of atoms: 0
13. Determined number of stereocenters of chemical bonds: 0
14. No Determine the number of stereocenters of chemical bonds: 0
15. The number of covalent bond units: 1
Properties and stability
1. Under the oxidation of strong oxidants such as potassium permanganate, potassium dichromate, and nitric acid, it is oxidized into benzoic acid. In the presence of a catalyst, benzoic acid can also be obtained by oxidation with air or oxygen. In the presence of sulfuric acid, benzaldehyde is obtained by oxidation with manganese dioxide below 40°C. The reduction reaction is carried out under the catalysis of nickel or platinum to generate methylcyclohexane. Using aluminum trichloride or ferric chloride as a catalyst, toluene reacts with halogen to produce ortho- and para-halogenated toluene. Under heating and light, it reacts with halogen to form benzyl halide. Reacts with nitric acid to produce ortho- and para-nitrotoluene. If mixed acid (sulfuric acid + nitric acid) is used for nitration, 2,4-dinitrotoluene can be obtained; continued nitration can produce 2,4,6-trinitrotoluene (T.N.T.). Toluene reacts with concentrated sulfuric acid or fuming sulfuric acid to form ortho- and para-toluenesulfonic acid. Under the catalytic action of aluminum trichloride or boron trifluoride, toluene undergoes an alkylation reaction with halogenated hydrocarbons, alkenes, and alcohols to obtain a mixture of alkyl toluenes. Toluene reacts with formaldehyde and hydrochloric acid to undergo a chloromethylation reaction to produce ortho- or para-methylbenzyl chloride.
2. Stability[26] Stable
3. Incompatible substances[27] Strong oxidants, acids, halogens, etc.
4. Polymerization hazards[28] No polymerization
Storage method
Storage Precautions[29] Stored in a cool, ventilated warehouse. Keep away from fire and heat sources. The storage temperature should not exceed 37°C. Keep container tightly sealed. should be kept away from oxidizer, do not store together. Use explosion-proof lighting and ventilation facilities. It is prohibited to use mechanical equipment and tools that are prone to sparks. The storage area should be equipped with emergency release equipment and suitable containment materials.
Synthesis method
1. The crude benzene fraction produced by coal coking contains 15-20% toluene. It was once the main source of toluene. 1.1-1.3kg of toluene can be recovered for each ton of coke produced. Since the 1950s, the world’s main source of toluene has shifted from coking by-products to catalytic reforming and hydrocarbon cracking. In 1982, petroleum toluene accounted for more than 96% of total production. Catalytic reformed oil contains 50-60% aromatics (volume), of which the toluene content can reach 40-45%; the aromatic content of pyrolysis gasoline is about 70% (mass), of which 15-20% is toluene.
2. Recovery of benzene from coking by-products High-temperature tar, a by-product of high-temperature coking, contains part of benzene. First, through the initial distillation tower, light benzene is obtained at the top of the tower, and heavy benzene is obtained at the bottom of the tower (heavy benzene is used as a raw material for preparing coumaron resin). Light benzene is first separated through the primary distillation tower, and the mixed fraction at the bottom of the tower is washed with acid and alkali to remove impurities, then steamed into the benzene blowing tower, and then distilled through the rectification tower to obtain pure benzene.
3. The platinum reforming method uses light gasoline (initial boiling point about 138°C) obtained by atmospheric distillation, intercepts the fraction above 65°C, and first uses a molybdenum-containing catalyst to catalytically hydrogenate to remove harmful impurities, and then It is reformed over a platinum catalyst, extracted with diethylene glycol ether solvent, and then distilled column by column to obtain benzene, toluene, xylene and other products.
4. Use light gasoline (initial boiling point about 138°C) obtained by atmospheric distillation, intercept the fraction above 65°C, first pass through a molybdenum-containing catalyst, catalytically hydrogenate to remove harmful impurities, and then pass through a platinum catalyst. Reform, extract with diethylene glycol ether solvent, and then rectify to obtain benzene, toluene, xylene and other products.
5. Slowly add 98% sulfuric acid to toluene, mix well and complete the thiophene reaction. Leave it for 0.5h to separate the lower acid solution. If the sulfuric acid test is qualified, the pickling is completed. Then wash thoroughly with distilled water until the sulfur compound content is acceptable. If it is unqualified, wash with 15% to 20% sodium hydroxide solution, then wash with water until the pH is qualified, separate the water layer and add anhydrous calcium chloride for dehydration. Finally, distillation is performed, and the 110-111°C fraction is collected, which is the finished product.
Purpose
1. Widely used as organic solvents and raw materials for synthetic medicines, coatings, resins, dyes, explosives and pesticides, etc., and used as chromatographic analysis standard materials and analytical reagents.
2. Toluene can be used as a raw material for the production of benzene and many other chemical products. Such as thinners and resin solvents used in paint, varnish, lacquer, adhesive and ink manufacturing industries and tinna water formulations; solvents used in chemical and manufacturing industries; especially suitable for the two processes of extraction and degreasing. It is also a raw material for chemical synthesis. It can also be used as a blending component of gasoline to increase the octane number. It is also a solvent for paints, inks and nitrocellulose. A series of intermediates produced from toluene are called toluene-based intermediates. In the chemical industry, it is mainly used to produce benzene and xylene. Its main downstream products are nitrotoluene, benzoic acid, benzyl chloride, m-cresol, toluene diisocyanate, etc. It can also produce many pesticides and pharmaceutical intermediates. In addition, toluene has excellent organic matter solubility properties and is a widely used organic solvent. Toluene is easily chlorinated to produce benzene-chloromethane or benzene-chloromethane, which are good industrial solvents; it is also easily nitrated to produce p-nitrotoluene or o-nitrotoluene, which are both raw materials for dyes; It is also easily sulfonated to produce o-toluenesulfonic acid or p-toluenesulfonic acid, which are raw materials for dyes or saccharin. Toluene vapor mixes with air to form an explosive substance, so it can be used to make dynamite.
3. Plant ingredient leaching agent. Used extensively as solvents and high-octane gasoline additives.
4. Used as analytical reagents, such as solvents, extraction separation agents, and chromatographic analysis reagents. It is also used as a cleaning agent and in organic synthesis of dyes, spices, benzoic acid, etc.
5. Used for blending with gasoline and as the main raw material for the production of toluene derivatives, explosives, dye intermediates, drugs, etc. [30]
�. Toluene vapor mixes with air to form an explosive substance, so it can be used to make dynamite.
3. Plant ingredient leaching agent. Used extensively as solvents and high-octane gasoline additives.
4. Used as analytical reagents, such as solvents, extraction separation agents, and chromatographic analysis reagents. It is also used as a cleaning agent and in organic synthesis of dyes, spices, benzoic acid, etc.
5. Used for blending with gasoline and as the main raw material for the production of toluene derivatives, explosives, dye intermediates, drugs, etc. [30]
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