Thiophene Thiophene
Structural formula
| Business number | 030E |
|---|---|
| Molecular formula | C4H4S |
| Molecular weight | 84.14 |
| label |
Monosulfadiene pentacyclic, Thiofuran, thiazoline, Thiolane, Thiofuran, heterocyclic compounds, Sulfur compound solvent |
Numbering system
CAS number:110-02-1
MDL number:MFCD00005413
EINECS number:203-729-4
RTECS number:XM7350000
BRN number:103222
PubChem number:24845982
Physical property data
1. Properties: colorless liquid with benzene odor.
2. Boiling point (ºC, 101.3kPa): 84.16
3. Melting point (ºC): -38.3
4. Relative density (g/mL, 20/4ºC): 1.06482
5. Relative vapor density (g/mL, air=1): 2.9
6. Refractive index (20ºC): 1.52890
7. Viscosity (mPa·s, 20ºC): 0.654
8. Flash point (ºC): -9
9. Fire point (ºC): 395
10. Heat of evaporation (KJ/mol, 25ºC): 34.62
11. Heat of evaporation (KJ/mol, b.p.): 31.493
12. Heat of fusion (KJ/ kg): 5.092
13. Heat of formation (KJ/mol, 25ºC, liquid): 81.73
14. Heat of combustion (KJ/mol, 25ºC, liquid): 2828.39
15. Critical temperature (ºC): 307
16. Critical pressure (MPa): 5.69
17. Vapor pressure (kPa, 25ºC): 10.6
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18. Lower explosion limit (%, V/V): 1.5
19. Upper explosion limit (%, V/V): 12.5
20. Solubility: Insoluble in water, but miscible with most organic solvents such as alcohol, ether, and benzene.
Toxicological data
It is easy to be absorbed through the skin when it touches the skin or it is easy to cause poisoning by inhaling the vapor and dust. Toxic and flammable. The LD50 of mice after inhalation for 2 hours is 9.5mg/L.
Absorption through the skin or inhalation of its vapor can cause poisoning. It mainly stimulates the central nervous system, and its blood toxicity is 1/5 of benzene. Subcutaneous injection of MLD into rabbits: 830mg/kg. Mice that inhale 30mg/L can die within 20 to 80 minutes.
Ecological data
This substance may be harmful to the environment and special attention should be paid to water bodies.
Molecular structure data
1. Molar refractive index: 24.63
2. Molar volume (cm3/mol): 78.9
3. Isotonic specific volume (90.2K): 190.4
4. Surface tension (dyne/cm): 33.9
5. Polarizability (10-24cm3 ): 9.76
Compute chemical data
1. Hydrophobic parameter calculation reference value (XlogP): 1.8
2. Number of hydrogen bond donors: 0
3. Number of hydrogen bond acceptors: 0
4. Number of rotatable chemical bonds: 0
5. Number of tautomers:
6. Topological molecular polar surface area (TPSA): 0
7. Number of heavy atoms: 5
8. Surface charge: 0
9. Complexity: 22.8
10. Number of isotope atoms: 0
11. Determine the number of atomic stereocenters: 0
12. Uncertain number of atomic stereocenters: 0
13. Determine the number of chemical bond stereocenters Number: 0
14. Number of uncertain stereocenters of chemical bonds: 0
15. Number of covalent bond units: 1
Properties and stability
Colorless fluid liquid with an aromatic odor similar to benzene. Flammable. Toxic, poisoning may occur if absorbed through skin or inhaled vapor. No contact with strong oxidizing agents.
Chemical properties: Thiophene does not decompose when heated to 850°C, but is converted into 2,2′-bithiophene and 3,3′-bithiophene when passing through a red hot pipe. Dissolved in concentrated sulfuric acid, it turns from red to brown. It appears blue in sulfuric acid-nitrite. Indophenine is generated in a concentrated sulfuric acid solution of isatin. This is a reaction unique to the thiophene ring;
Heating the cyclohexane solution of thiophene with nitric acid will produce not only 2-nitro and 2,5-dinitrothiophene, butene di acid and oxalic acid. When thiophene is heated to 90°C with 100% phosphoric acid, 2,4-bis(α-thienyl)tetrahydrothiophene is generated;
Thiophene, like benzene, can undergo alkylation, sulfonation, and nitration , halogenation, cyanation, chloromethylation and other nuclear substitution reactions.
Storage method
Store in a cool, ventilated warehouse. Keep away from fire and heat sources. The storage temperature should not exceed 30℃. 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
Thiophene exists in coal tar and shale oil. The waste acid produced by crude benzene washing can be used as raw material. It is hydrolyzed at 110-150°C. The gas generated during hydrolysis enters the overhead condenser through the hydrolysis distillation tower, and the condensed concentrate is obtained. The distillate contains about 15%-25% thiophene, about 50%-60% xylene, and also contains benzene, toluene, methylthiophene and some unknown substances. Approximately 10kg of distillation product can be extracted from each ton of waste acid. After dehydration with solid sodium hydroxide and purification through distillation, a thiophene product with a content of 90%-95% can be obtained. To chemically synthesize thiophene, butane and sulfur can be used as raw materials. Butane is first dehydrogenated and then cyclically formed with sulfur to form thiophene. It is obtained by reacting 1,4-dicarbonyl compound with phosphorus trisulfide in laboratory preparation.
Refining method: The general refining method is to wash thiophene with dilute hydrochloric acid and water respectively, dry it with calcium chloride, and distill it with a 90cm high distillation tower to obtain a product with a purity of 99% (mol). To obtain high-purity products, industrial thiophene can be washed with dilute hydrochloric acid, sodium hydroxide, and distilled water respectively, dried with calcium chloride, and then used a distillation tower with a column height of 235cm and filled with a 2.4mm stainless steel Raschig ring. The reflux ratio is: Carry out atmospheric distillation at a ratio of 50:1, collect the middle fraction, crystallize 6 times in steps, and then treat it with mercury chloride in an ethanol-sodium acetate solution. The resulting solid is added with hydrochloric acid and heated to reflux. After cooling, it is extracted with pentane. Thiophene. The pentane solution is dried with calcium chloride and then fractionated to obtain a highly pure product.
Purpose
Used to prepare drugs, dyes, etc. It is mainly used as an intermediate in the pharmaceutical industry and is used in the preparation of drugs such as thiopyridine and pyrantel. It is also used as raw material for synthetic resin and dye industry. Also used as organic solvent. As a chemical reagent, it is used as a standard reagent for chromatographic analysis.
