3-methylpyridine 3-Picoline
Structural formula
| Business number | 02YE |
|---|---|
| Molecular formula | C6H7N |
| Molecular weight | 93 |
| label |
3-Picoline, β-methylpyridine, β-picolin, 3-methylpyridine, B-Picolin, β-Methylpyridine, 3-Methyl-pyridine, β-Methylpyridine, β-Picoline, Heterocyclic compounds |
Numbering system
CAS number:108-99-6
MDL number:MFCD00006402
EINECS number:203-636-9
RTECS number:TJ5000000
BRN number:1366
PubChem number:24887350
Physical property data
1. Properties: colorless or yellow hygroscopic liquid with sweet taste. [1]
2. Melting point (℃): -18.1[2]
3. Boiling point (℃): 143~144[3]
4. Relative density (water=1): 0.96[4]
5. Relative vapor density (air=1): 3.21[5]
6. Saturated vapor pressure (kPa): 0.6 (20℃)[6]
7. Heat of combustion (kJ/mol): -3420.0[7]
8. Critical pressure (MPa): 4.4[ 8]
9. Octanol/water partition coefficient: 1.20[9]
10. Flash point (℃): 38 ( CC)[10]
11. Ignition temperature (℃): 500[11]
12. Explosion limit (%): 8.7[12]
13. Lower explosion limit (%): 1.3[13]
14. Solubility: soluble in water, soluble in most organic solvents such as ethanol and ether. [14]
15. Viscosity (mPa·s, 25ºC): 0.87228
16. Vapor pressure (kPa, 81.3℃): 12.87
17. Heat of evaporation (KJ/mol, 25ºC): 45.2625
18. Heat of fusion (KJ/mol): 10.33
19. Heat of formation (KJ/ mol, liquid): 68.27
20. Heat of combustion (KJ/mol, 25ºC): 3424.86
21. Specific heat capacity (KJ/(kg·K), 25ºC, constant pressure) : 1.71
22. Volume expansion coefficient (K-1, 25ºC): 0.000969
Toxicological data
1. Skin/eye irritation
Standard Draize test: rabbit, skin contact: 200μL/24H, severity of reaction: severe.
Standard Draize test: Rabbit, eye contact: 100μL/24H, severity of reaction: severe.
2. Acute toxicity: Rat oral LD50: 400mg/kg; Rat inhalation LCLo: 11820mg/m3/5H; Rat intraperitoneal LD50: 150mg/ kg; mouse intraperitoneal LD50: 596mg/kg; mouse intravenous LD50: 298mg/kg; rabbit skin contact LDLo: 200mg/kg; guinea pig skin contact LD50: 1mg/kg; quail oral LD50: 1mg/kg ; Oral LD50 of wild birds: 1mg/kg;
3. Acute toxicity[15] LD50: 400mg /kg (rat oral); 1000mg/kg (guinea pig transdermal)
4. Irritation[16]
Rabbit transdermal: 200ul (24h), severe stimulation.
Rabbit eye: 100ul (24h), severe irritation.
Ecological data
1. This substance is slightly harmful to water.
2. Ecotoxicity No data available
3. Biodegradability No data
4. Non-biodegradability[17] In the air, when the concentration of hydroxyl radicals is 5.00×105/cm3 , the degradation half-life is 12d (theoretical).
Molecular structure data
1. Molar refractive index: 29.16
2. Molar volume (cm3/mol): 98.9
3. Isotonic specific volume (90.2K ): 239.0
4. Surface tension (dyne/cm): 34.0
5. Polarizability: 11.56
Compute chemical data
1. Reference value for hydrophobic parameter calculation (XlogP): None
2. Number of hydrogen bond donors: 0
3. Number of hydrogen bond acceptors: 1
4. Number of rotatable chemical bonds: 0
5. Number of tautomers: none
6. Topological molecule polar surface area 12.9
7. Number of heavy atoms: 7
8. Surface charge: 0
9. Complexity: 52.1
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: 0
14. Number of uncertain chemical bond stereocenters: 0
15. Number of covalent bond units: 1
Properties and stability
1. Its chemical properties are similar to those of pyridine. It is alkaline and can form salts with inorganic and organic acids. Form addition compounds with inorganic salts, alkyl halides, etc. During hydrogenation, 3-methylpiperidine or pyridine can be generated depending on the reaction conditions. When oxidized, pyridine-3-carboxylic acid (nicotinic acid, C5H4N·CO2H) or pyridine is generated.
2. Health hazards: Invasion route: inhalation, ingestion, percutaneous absorption. Health hazards: Exposure to this product may cause fatigue, general weakness, drowsiness, etc. In severe cases, neurological symptoms may occur, such as unsteady gait, temporary loss of consciousness, etc. Toxicology information and environmental behavior Toxicity: Low toxicity. Acute toxicity: LD50400~800mg/kg (oral administration to rats); LD50800~1600mg/kg (oral administration to mice). Hazardous characteristics: Flammable, there is a risk of combustion and explosion when exposed to high heat, open flame or contact with oxidants. It decomposes when heated and releases toxic nitrogen oxide fumes. Combustion (decomposition) products: carbon monoxide, carbon dioxide, nitrogen oxides. Protective measures: Respiratory protection: When you may be exposed to its vapor, you should wear a filter gas mask (half mask). When necessary, it is recommended to wear an air respirator. Eye protection: Wear chemical safety glasses. Body protection: Wear anti-toxic substance penetration overalls. Hand protection: Wear rubber gloves. Others: Smoking is strictly prohibited at the work site. After work, take a shower and change clothes. Pay attention to personal hygiene.
3. Stability[18] Stable
4. Incompatible substances[19] Acids, acid chlorides, strong oxidants, chloroform
5. Conditions to avoid contact[20] Heat
6. Aggregation hazards[21] No aggregation
Storage method
Storage Precautions[22] Store in a cool, ventilated warehouse. Keep away from fire and heat sources. The storage temperature should not exceed 37°C. Keep container tightly sealed. They should be stored separately from oxidants, acids, etc., and avoid mixed storage. 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. It is recovered from coal coking by-products and also produced by synthetic methods. Reaction of acetaldehyde, formaldehyde and ammonia. SiO2-Al2O2-Bi2O3 is used as the catalyst. The molar ratio of the raw materials is acetaldehyde: 37% formaldehyde: ammonia = 1.648: 3.096. The reaction is carried out at 432°C. The yield of pyridine is 48.4% and the yield of 3-picoline is 27.0%. . Changing the catalyst composition and other reaction conditions can adjust the production ratio of the product. By selecting appropriate ingredients and catalysts, and using hexamethylenetetramine instead of ammonia, the yield of 3-methylpyridine can reach 59.7%.
2. Refining method: The same as the refining method of 2-methylpyridine. Crude 3-methylpyridine contains many impurities, and most of the impurities can be removed by azeotropic distillation with water. It is difficult to separate 4-methylpyridine and 2,6-lutidine by fractionation. Most of them use the different solubility of their added compounds to achieve the purpose of separation. For example, after treatment with copper sulfate solution, the addition product is collected, decomposed with calcium hydroxide, and then refined by steam distillation.
Purpose
1. Mainly used in the manufacture of vitamin B6, nicotinic acid and nicotinamide, nicotinic acid, nicotinic acid and other drugs; also used as solvent, nicotinic acid, nicotinamide, nicothamide, alcohol denaturant, dye intermediate , resin intermediates, rubber vulcanization accelerators, raw materials for pesticides, waterproofing agents, and additives for film photosensitizers.
2. Used as a solvent in organic synthesis and in the preparation of nicotine and nicotinamide. [23]
