description
Biphenyl is also called phenyl benzene, it is formed by two connected phenyl compounds, is white or colorless to light yellow crystal plate, industrial products is slightly yellow with special fragrance. The melting temperature is 69.2 ℃, boiling point is 69.2 ℃. Insoluble in water, but soluble in organic solvents. Commonly used for organic synthesis precursor, is one of the key components of the organic high temperature heating medium. Its derivatives include benzidine, diphenyl ether, eight bromine diphenyl ether, polychlorinated biphenyls, etc.
Natural biphenyl exists in coal tar, crude oil and natural gas, the mass fraction is 0.20% to 0.20% in coal tar, current preparation methods of biphenyl include coal tar extraction and chemical synthesis.
The chemical bond in the middle of biphenyls can rotate freely, but if there were bulky groups in the four orthos, restricts rotation and would produce resistance isomer. This type of compounds (such as BINAP) can be used as a chiral ligands. substituted biphenyl by Suzuki reaction and Ullmann coupling reactions.
Biphenyl is a kind of important organic raw materials, widely used in medicine, pesticides, dyes, liquid crystal materials, etc. Can be used in the synthesis of plasticizer, preservatives, can also be used to make fuel, engineering plastic and high energy fuel.
Chemical Properties
Biphenyl is a white or slightly yellow scaly crystal, has a unique fragrance. Insoluble in water, acid and alkali, soluble in alcohol, ether, benzene and other organic solvents.
Reactions
Biphenyl is a neutral molecule and fairly non-reactive due to lack of functional group. However, biphenyl participates in many of the reactions that are typical for benzene, for example, substitution reactions upon treatment with halogens in the presence of a Lewis acid. Also, it is required to convert biphenyls into the structural analogs containing the active groups in order for it to be able to use for synthetic intermediate for the production of a host of other organic compounds such as emulsifiers, optical brighteners, crop protection products, plastics and pharmaceuticals (Johansson and Olsen, 2008). For this, it is important to consider the o,p-directing and/or mdirecting effect, especially when substitution at a specific position is desired i.e. mono, di-, tri- or tetra- substitutions. It is possible to acetylate the carboxylic part, also various other biphenyl derivative synthesis are possible by carrying out the amination, halogenation, sulphonation, alkylation, hydroxylation, metal complexation etc.
Uses
Biphenyl is used in organic syntheses, heat transfer fluids, dye carriers, food preservatives, as an intermediate for polychlorinated biphenyls, and as a fungistat in the packaging of citrus fruits.
Biphenyl with high thermal stability and low vapor pressure, long often alone or with diphenyl ether and blend to used as heating medium. Component of biphenyl and terphenyl (including Biphenyl 13%, terphenyl 61%) can effectively absorb radiation, can be used as a heating medium for nuclear power plant. And three terphenyl([91-94-4]) is the byproduct of benzene pyrolysis to produce Biphenyl, according to the different reaction conditions, the proportion of the reaction product of biphenyl and terphenyl within a certain range of change, in general, Biphenyl: terphenyl=78:1. Biphenyl is used as a carrier, and its derivatives of ethyl biphenyl, diethyl biphenyl and triethyl biphenyl senior can be used as solvents, used in pressure sensitive dye solvent of carbon paper.
Production Method
Biphenyl occurs naturally in coal tar, crude oil, and natural gas and can be isolated from these sources via distillation. It can also be synthesized synthetically by using a Grignard reagent such as phenylmagnesium bromide and reacting it with bromobenzene, reacting fluorobenzene with phenyl lithium or reacting benzyne with phenyl lithium as follows.
Ullmann et al. (1904), discovered that heating iodobenzene with a copper powder catalyst leads to the formation of biphenyl with high purity. Meanwhile, this reaction has become a textbook case and it is widely used in synthetic chemistry due to its versatility in the association of substituted phenyls to complex biphenyl derivatives.
The synthesis of biphenyl out of iodobenzene on copper essentially consists of three steps: dissociation of iodobenzene (C6H5I) to phenyl (C6H5) and iodine, diffusion of phenyl to find another phenyl as a reaction partner, and association to form biphenyl (C12H10). The dissociation of iodobenzene by thermal activation takes place at 180 K and biphenyl is formed at 210 K for multilayer (Weiss et al., 1998) and 300 K for submonolayer iodobenzene on Cu(III) [Yang et al., 1995; Xi and Bent, 1992].
Toxicity
Biphenyls are low toxic and irritating to humans. Its steam can stimulate eyes, nose and trachea, cause loss of appetite and vomiting, and has certain toxicity to the nervous system, digestive system and kidney. The oral LD50 of rats was 3.28g/kg. The maximum allowable concentration in the workplace is > 1mg / m3 (coexisting with diphenyl ether). It can stimulate, damage the heart, liver and kidney, and have toxic effects on the reproductive system of humans and other animals. This product has stimulating effect and damages myocardium, liver and kidney. LD50: 3280mg / kg in rats (25% olive oil solution) and 240mg / kg in rabbits. It exists in flue-cured tobacco, oriental tobacco and flue gas.
Toxicity
ADI 0~0.05 mg/kg (under some conditions 0.05~0.25 mg/kg FAO/WHO, 2001).
LD50 3.28~5.04 g/kg (mice, through the mouth).
Limited use
FAO/WHO, the United States and Canada regulations, its residual ≤110 mg/kg or less; Japan, France, Germany, the Netherlands, rules ≤70 mg/kg or less.
Preparation
High temperature coal tar contains about 3.0% biphenyl, which can be recovered from washing oil fraction. In 1926, Dow Chemical Company of the United States began to produce biphenyl by pyrolysis of benzene. Another source of biphenyl is the by-product of thermal dealkylation of toluene to benzene. With the development of this process, the byproduct biphenyl of this process has gradually become the main source of biphenyl. In the laboratory, the diazonium salt obtained by diazotization of aniline is added to benzene, and then the mixture is slowly added to sodium hydroxide solution, stirred for reaction, and the temperature slowly rises from below 5 ℃ to 30-35 ℃. Biphenyl is formed after reaction for 8 hours.
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.
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.
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).
Uses
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.
Uses
Biphenyl is used to prevent fungal attack on stored citrus fruit. It
is impregnated into fruit wraps.
Uses
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.
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.
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.
Aroma threshold values
Detection: 0.5 ppb
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
Mechanism of action
Inhibits sporulation, lipid peroxidation
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.
Toxics Screening Level
The ITSL of 13 μg/m3 is associated with an 8-hour averaging time.
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
