Сек-Бутилбензол

Description

Sec-Butylbenzene (2-phenylbutane) is an aromatic hydrocarbon, a clear, colorless liquid. It is obtained by alkylation of benzene with n-butenes over an acid catalyst. The molecule has an asymmetric carbon atom, so the commercial product is a racemate - this is reflected in the synonyms of the card by the entries (±)-sec-butylbenzene and (RS)-2-phenylbutane.

Application

• raw materials for the joint production of phenol and methyl ethyl ketone: sec-butylbenzene is oxidized with an oxygen-containing gas to hydroperoxide, which is then decomposed on an acid catalyst to form phenol and methyl ethyl ketone (a variant of the Hock process, developed by Sumitomo - US patents 5,298,667, 5,304,684 and subsequent)
• solvent for organic substances
• intermediate product of organic synthesis
• analytical sample for monitoring the composition of aromatic fractions

Industrial interest in this scheme is associated with the raw material base: the route through sec-butylbenzene uses butenes instead of propylene and produces methyl ethyl ketone instead of acetone, which is important given the rapid growth in demand for phenol and the rise in propylene prices.

Identification

• CAS No.: 135-98-8 (Additional No. 36383-15-0)
• Formula: C10H14
• EU number: 205-227-0
• BRN: 1903902
• NSC Number: 8466
• DSSTox ID: DTXSID2022333
• RTECS number: CY9100000
• HS code: 2902 90 00
• Synonyms: benzene, (1-methylpropyl)-; benzene, sec-butyl-; (1-methylpropyl)benzene; 2-phenylbutane; (α-methylpropyl)benzene; (±)-sec-butylbenzene; (RS)-2-phenylbutane; NSC 8466

Physico-chemical indicators

• Molecular weight: 134.22
• Exact weight: 134.22
• Color and form: colorless liquid; appearance: clear liquid
• Density: 0.8580 g/cm³ at 25 °C
• Melting point: −82.7 °C
• Freezing point: −75.68 °C
• Boiling point: 173.5 °C
• Flash point: 114°F
• Refractive index: n20/D 1.489 (lit.)
• Solubility in water: 17.6 mg/l
• Steam pressure: 4 mm Hg. Art. at 37.7 °C
• Vapor Density: 4.62 (air = 1)
• Weight per gallon: 7.2 lbs at 20°C
• Relative dielectric constant: 2.357 at 93.2 K
• Standard enthalpy of formation (liquid): −66.4 kJ/mol
• Heat of vaporization: 47.98 kJ/mol at 25 °C
• Henry's law constant: 0.018 atm m³/mol at 25 °C (calculated)
• Rate constant for reaction with hydroxyl radicals: 8.5 × 10⁻¹² cm³/(molecule s) at 25 °C (calculated)
• Conversion factor: 5.49 mg/m³ ≈ 1 ppm at 1 atm
• PSA Features: 0
• XLogP3: 4.57
• Storage conditions: 2–8 °C

Fire and explosion hazard

• Easily ignites when exposed to open flame, high temperature and strong oxidizer; When burning, irritating smoke is released
• Flammability limits: lower 0.8% vol., upper 6.9% vol.
• Explosive when mixed with air

Toxicity

• Oral, rats, LD50: 2240 µl/kg

GHS classification and safety precautions

• Hazard: H226 (79.22%) - flammable liquid and vapor; measures P210, P233, P240, P241, P242, P243, P264, P273, P280, P301+P310, P302+P352, P303+P361+P353, P305+P351+P338, P321, P331, P332+P313, P337+P313, P362, P370+P378, P391, P403+P235, P405, P501. Data aggregated from 83 companies across 9 notifications to the ECHA C and L register
• Warning: H226 is flammable liquid and vapour; measures P210, P233, P240, P241, P242, P243, P280, P303+P361+P353, P370+P378, P403+P235, P501
• Hazard statements cards: H226, H315, H411; measures P273, P391, P403+P235, P501
• Hazard class code: 10-39/23/24/25-23/24/25-11-51/53-38
• Safety instructions: 23-24/25-45-36/37-16-7-61
• Tags: F, T, N, Xi
• WGK Germany: 3
• Packaging level: III; hazard category: 3
• Transport code: UN 2709, class 3, packing group III

Protective equipment and actions in case of accident

Personal protective equipment for the butylbenzene group: chemically resistant gloves, safety shoes, safety glasses. When extinguishing fires involving material, breathing apparatus with an overpressure cylinder is used.

• If the material is on fire: extinguishing begins only if it is possible to shut off the flow. Water is supplied in large quantities in the form of a mist; compact jets may not be effective. All affected containers are cooled with an abundant supply of water, water is supplied from the maximum possible distance. Use foam, dry chemical or carbon dioxide. Wastewater should not be allowed to enter sewers or water sources.
• If the material does not burn: exclude sparks, flames and other sources of ignition, block the path of the material to reservoirs and sewers, and, if necessary, embank the spill. The leak is stopped if it does not pose an undue danger to personnel. Vapors are knocked down with water sprays
• Prevention: avoid inhaling vapors, stay on the leeward side, avoid contact of the material with the body, do not touch damaged packaging without protective equipment, wash off material that comes into contact with the skin with plenty of soap and water, in case of possible contact, wear chemical protective clothing

Storage and disposal

Storage at 2–8 °C. The warehouse is ventilated, away from open fire and high temperature, away from oxidizing agents; The packaging is complete, loading and unloading without shock. SRP Disposal Recommendation: It is preferable to replace the product with a chemical equivalent with less risk of occupational exposure and environmental contamination; unused material should be sent for authorized use or returned to the manufacturer or supplier. Final disposal takes into account the impact on air quality, possible migration in soil and water, effects on animals, aquatic life and vegetation, as well as environmental and public health requirements.