Biphenyl

Description

Biphenyl, also called diphenyl, consists of two benzene rings joined by a single bond. It exists as colorless to yellowish crystals, has a distinctive odor, and occurs naturally in oil, natural gas, and coal tar.

Description

Biphenyl is an organic compound with chemical formula of C12H10. It is a white crystalline powder, insoluble in water, soluble in ether, ethanol, carbon tetrachloride, dioxane, aromatic hydrocarbons, etc. it is mainly used as solvent, heat transfer agent, fruit mildew inhibitor and organic synthesis.

Chemical properties

1,1'-Biphenyl is a clear colorless liquid with a pleasant odor and stable organic compound. It is combustible at high temperatures, producing carbon dioxide and water when combustion is complete. Partial combustion produces carbon monoxide, smoke, soot, and low molecular weight hydrocarbons. It is used extensively in the production of heat-transfer fl uids, for example, as an intermediate for polychlorinated biphenyls, and dye carriers for textile dyeing. It is also used as a mold retardant in citrus fruit wrappers, in the formation of plastics, optical brighteners, and hydraulic fluids.

Physical properties

White scales with a pleasant but peculiar odor. Odor threshold concentration is 0.83 ppb (quoted, Amoore and Hautala, 1983).

Occurrence

Reported found in coal tar, bilberry, carrots, peas, potato, bell pepper, rum, cocoa, tomato, coffee, roasted peanuts, olive (Olea europae), buckwheat and tamarind (Tamarindus indica L).

The Uses of Biphenyl

Biphenyl is used to prevent fungal attack on stored citrus fruit. It is impregnated into fruit wraps.

The Uses of Biphenyl

Biphenyl is used as an antifungal agent to preserve citrus fruit, in citrus wrappers to retard mold growth, in heat transfer fluids, in dye carriers for textiles and copying paper, as a solvent in pharmaceutical production, in optical brighteners, and as an intermediate for the production of a wide range of organic compounds.

The Uses of Biphenyl

As heat transfer agent; fungistat for oranges (applied to inside of shipping container or wrappers); in organic syntheses.

Definition

ChEBI: A benzenoid aromatic compound that consists of two benzene rings connected by a single covalent bond. Biphenyl occurs naturally in coal tar, crude oil, and natural gas. Formerly used as a fungicide for citrus crops.

What are the applications of Application

Biphenyl is a starting material for the production of polychlorinated biphenyls

Preparation

By thermal dehydrogenation of benzene.

Definition

An organic compound having a structure in which two phenyl groups are joined by a C–C bond.

What are the applications of Application

Biphenyl is an important organic raw material, which is widely used in medicine, pesticide, dye, liquid crystal materials and other fields. It can be used to synthesize plasticizers and preservatives, and can also be used to manufacture fuels, engineering plastics and high-energy fuels. Biphenyls are found in coal tar, crude oil and natural gas. The preparation methods of biphenyl include chemical synthesis of biphenyl by pyrolysis of benzene and separation and extraction of biphenyl from various coal tar oil fractions. The mass fraction of biphenyl in coal tar is 0.20% - 0.40%. Coal tar extraction and chemical synthesis coexist. Biphenyl is combustible. In case of high temperature, open fire and oxidant, it is dangerous to burn. It should be stored in a cool and ventilated warehouse away from kindling and heat source. It should be stored separately from oxidants and strong acids. It should be loaded and unloaded gently to keep the package intact. Biphenyl is used as heat exchanger and impregnator of fruit packaging paper. Biphenyl can be used in organic synthesis. Biphenyl is the raw material of engineering plastics polysulfone. It is used to prepare Trichlorobenzene and pentachlorophenyl. Biphenyl is used as heat carrier, preservative, dye and so on. Biphenyl is used as a reference material for chromatographic analysis. Biphenyl is the intermediate of rodenticides rodenticide modek and bromadine, and it is an organic carrier with good performance.

Aroma threshold values

Detection: 0.5 ppb

Synthesis Reference(s)

Journal of the American Chemical Society, 83, p. 1251, 1961 DOI: 10.1021/ja01466a056
Tetrahedron Letters, 25, p. 391, 1984 DOI: 10.1016/S0040-4039(00)99891-5

General Description

A clear colorless liquid with a pleasant odor. Flash point 180°F. Insoluble in water. Vapors are heavier than air. Used to manufacture other chemicals and as a fungicide.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Biphenyl is incompatible with oxidizers.

Health Hazard

Exposures to 1,1’-biphenyl cause acute effects with symptoms that include, but are not limited to, polyuria, accelerated breathing, lacrimation, anorexia, weight loss, muscular weakness, coma, fatty liver cell degeneration, and severe nephrotic lesions. Exposure to biphenyl fumes for short periods of time causes nausea, vomiting, irritation of the eyes and respiratory tract, and bronchitis. Breathing small amounts of 1,1’-biphenyl over long periods of time causes damage to the liver and the nervous system of exposed workers. Breathing the mists, vapors, or fumes may irritate the nose, throat, and lungs. Depending on the concentration and duration of exposure, the symptoms include, but are not limited to, sore throat, coughing, labored breathing, sneezing, a burning sensation, and the effects of CNS depression. Symptoms may include headache, excitation, euphoria, dizziness, incoordination, drowsiness, light-headedness, blurred vision, fatigue, tremors, convulsions, loss of consciousness, coma, respiratory arrest, and death, depending on the concentration and duration of exposure

Fire Hazard

Combustible. Emits toxic fumes under fire conditions.

Flammability and Explosibility

Non flammable

Safety Profile

Poison by intravenous route.Moderately toxic by ingestion. A powerful irritant byinhalation in humans. Human systemic effects byinhalation of very small amounts: flaccid paralysis, nauseaor vomiting, and other unspecified gastrointestinal effects.Que

Potential Exposure

Biphenyl is a fungicide (pesticide). It is also used as a heat transfer agent, dye carrier, and as an intermediate in organic synthesis.

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least 15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Do not induce vomiting.

Source

Present in coal tar at a concentration of 2.72 mg/g (Lao et al., 1975). Detected in woodpreserving creosotes at a concentration of 2.1 wt % (Nestler, 1974). Typical concentration of biphenyl in a heavy pyrolysis oil is 2.3 wt % (Chevron Phillips, May 2003).

Environmental Fate

Biological. Reported biodegradation products include 2,3-dihydro-2,3-dihydroxybi phenyl, 2,3-dihydroxybiphenyl, 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate, 2-hydroxy- 3-phenyl-6-oxohexa-2,4-dienoate, 2-oxopenta-4-enoate, phenylpyruvic acid (Verschueren, 1983), 2-hydroxybiphenyl, 4-hydroxybiphenyl and 4,4′-hydroxybiphenyl (Smith and Rosazza, 1974). Under aerobic conditions, Beijerinckia sp. degraded biphenyl to cis-2,3- dihydro-2,3-dihydroxybiphenyl. In addition, Oscillatoria sp. and Pseudomonas putida degraded biphenyl to 4-hydroxybiphenyl and benzoic acid, respectively (Kobayashi and Rittman, 1982). The microbe Candida lipolytica degraded biphenyl into the following products: 2-, 3- and 4-hydroxybiphenyl, 4,4′-dihydroxybiphenyl and 3-methoxy-4-hydrox ybiphenyl (Cerniglia and Crow, 1981). With the exception of 3-methoxy-4-hydroxybiphe nyl, these products were also identified as metabolites by Cunninghanella elegans (Dodge et al., 1979). In activated sludge, 15.2% mineralized to carbon dioxide after 5 days (Freitag et al., 1985).
Photolytic. A carbon dioxide yield of 9.5% was achieved when biphenyl adsorbed on silica gel was irradiated with light (λ >290 nm) for 17 hours. Irradiation of biphenyl (λ >300 nm) in the presence of nitrogen monoxide resulted in the formation of
Chemical/Physical. The aqueous chlorination of biphenyl at 40°C over a pH range of 6.2 to 9.0 yielded o-chlorobiphenyl and m-chlorobiphenyl (Snider and Alley, 1979). In an acidic aqueous solution (pH 4.5) containing bromide ions and a chlorinatin
Biphenyl will not hydrolyze since it has no hydrolyzable functional group.

Metabolic pathway

Biphenyl is a stable compound. It has a restricted use as a fungistat applied to citrus packing material. This has generated studies on its toxicity and metabolism in mammals and residue studies in stored fruit. Only limited information on its environmental fate has been published.

storage

1,1’-Biphenyl should be kept stored in tightly closed containers in a cool, dry, isolated, and properly ventilated area, away from heat, sources of ignition, incompatibles, and contact with strong oxidizers.

Shipping

UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1—Poisonous materials, Technical Name Required.

Purification Methods

Crystallise biphenyl from EtOH, MeOH, aqueous MeOH, pet ether (b 40-60o) or glacial acetic acid. Free it from polar impurities by passage through an alumina column in *benzene, followed by evaporation. The residue has been purified by distillation in a vacuum and by zone refining. Treatment with maleic anhydride removes anthracene-like impurities. It has been recrystallised from EtOH followed by repeated vacuum sublimation and passage through a zone refiner. [Taliani & Bree J Phys Chem 88 2351 1984, Beilstein 5 H 576, 5 I 271, 5 II 479, 5 III 1726, 5 IV 1807.]

Degradation

Biphenyl is not subject to hydrolysis.

Incompatibilities

Mist may form explosive mixture with air. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.

Waste Disposal

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed.

Precautions

Occupational workers should be careful during use and chemical management because the fi nely dispersed particles of 1,1’-biphenyl form explosive mixtures in air