Ethylbenzene appears as a clear colorless liquid with an aromatic odor. Flash point 59°F. Less dense than water (at 7.2 lb / gal) and insoluble in water. Hence floats on water. Vapors heavier than air. Used as a solvent and to make other chemicals.
颜色/状态:
Colorless liquid
气味:
Aromatic odor
蒸汽密度:
3.66 (NTP, 1992) (Relative to Air)
蒸汽压力:
9.6 mm Hg at 25 °C
亨利常数:
Henry's Law constant = 7.88X10-3 atm-cu m/mol at 25 °C
Ethylbenzene is extensively metabolized, mainly to mandelic and phenylglyoxylic acids. These urinary metabolites can be used to monitor human exposures.
It is metabolized mainly in the liver through hydroxylation followed by conjugation and excretion of the metabolites in the urine. Major metabolites in rats are hippuric and benzoic acids (38%), 1-phenylethanol (25%), mandelic acid (15-23%), and phenylglyoxylic acid (10%). ... Major metabolites in humans are mandelic acid (65-70%) and phenylglyoxylic acid (20-25%).
Female assistants using mixture of xylenes & ethylbenzene as solvent in histology lab were exam. Avg air concn of (m + p)-xylene & ethylbenzene was between 56-68 & 34-41 ppm. Approx 1.1 to 1.4% of retained ethylbenzene was metabolized to 2-ethyl-phenol.
Ethylbenzene is metabolized mainly through hydroxylation and then through conjugation reactions from which numerous metabolites have been isolated. Hydroxylation of ethylbenzene to 1-phenylethanol is catalyzed by cytochrome P-450 isoforms CYP2E1 and CYP2B6. 1-Phenylethanol is conjugated to glucuronide, which then is either excreted or converted to subsequent metabolites. Oxidation of 1-phenylethanol yields acetophenone, which is both excreted in the urine as a minor metabolite and further transformed. Continued oxidation of the side chain leads to the sequential formation of 2-hydroxyacetophenone, 1-phenyl-1,2-ethanediol, mandelic acid, and phenylglyoxylic acid. Minor pathways (e.g., ring hydroxylation) include glucuronide and sulfate conjugation with hydroxylated derivatives to form glucuronides and sulfates that are excreted in the urine. In humans exposed via inhalation, the major metabolites of ethylbenzene in the urine are mandelic acid (70%) and phenylglyoxylic acid (25%). Following dermal exposure of humans, however, excretion of mandelic acid was shown to be only 4.6% of the absorbed dose, which may indicate differences in the metabolic fate between inhalation and dermal exposure routes. (L311)
IDENTIFICATION AND USE: Ethylbenzene is a colorless liquid with aromatic odor. It is used as an intermediate for the manufacture of the styrene monomer and as a resin solvent. It is also used as a component of automotive and aviation fuels. HUMAN EXPOSURE AND TOXICITY: Human exposure to ethylbenzene occurs mainly by inhalation. Ethylbenzene has low acute and chronic toxicity for humans. It is toxic to the central nervous system and is an irritant of mucous membranes and the eyes. Ethylbenzene vapor has a transient irritant effect on human eyes at 200 ppm in air. At 1000 ppm on the first exposure it is very irritating and causes tearing, but tolerance rapidly develops. At 2000 ppm eye irritation and lacrimation are immediate and severe; 5000 ppm causes intolerable irritation of the eyes and nose. Volunteers reported irritation and chest constriction after acute-duration exposures to 2,000 ppm ethylbenzene. These symptoms worsened as the concentration was increased to 5,000 ppm. Human exposures in the range of 2,000-5,000 ppm ethylbenzene were associated with dizziness and vertigo. Complete recovery occurs if exposure is not prolonged. Ethylbenzene exposure might be associated with hearing loss, neurobehavioral function impairment, and imbalance of neurotransmitters. Ethylbenzene is an inducer of liver microsomal enzymes. ANIMAL STUDIES: Drop application to rabbit eyes caused slight irritation and no corneal injury demonstrable by fluorescein staining. Standard testing on rabbit eyes gave an injury grade of 2 on a scale of 10. Eye irritation and lacrimation have been observed after acute-duration exposures in rats, mice, and guinea pigs exposed to >/= 1,000 ppm ethylbenzene. Lacrimation was observed in rats exposed to 382 ppm for 4 weeks. In contrast, no ocular effects were seen in rats or mice after a 13-week exposure to 975 ppm ethylbenzene. Mild irritation, reddening, exfoliation, and blistering have been reported in rabbits when ethylbenzene was applied directly on the skin. Slight irritation of the eye and corneal injuries were observed in rabbits when ethylbenzene was instilled onto the eyes. A 50% respiratory depression was observed in mice exposed to >/= 1,432 ppm for 5-30 minutes. Results of 4- and 13-week studies indicate that intermediate-duration oral exposure to ethylbenzene produces effects to the liver. Acute-duration and intermediate-duration studies in animals suggest that the auditory system is a sensitive target of ethylbenzene toxicity. Significant losses of outer hair cells in the organ of Corti have been observed in rats after acute-duration exposure >/= 400 ppm and intermediate-duration inhalation exposure to >/= 200 ppm ethylbenzene. Guinea pigs exposed to sublethal concentrations of ethylbenzene (</= 10,000 ppm for <100 minutes) showed "moderate" pulmonary edema and congestion. These findings had disappeared in animals after a 4-8-day recovery period, suggesting that these pathological effects in the lung are reversible. Rats inhaling 600, 1200, or 2400 mg ethylbenzene/cu m for 24 hr/day from days 7-15 of pregnancy showed mild toxicity. The highest dose retarded skeletal development and weight gain in the fetuses and increased the incidence of extra ribs. Sacral displacement with abnormal development was observed in 2 instances. Thus, ethylbenzene, has some embryotoxic and teratogenic activity. ECOTOXICITY STUDIES: The acute toxicity of ethylbenzene to algae, aquatic invertebrates and fish is moderate. No information is available regarding chronic exposure of aquatic organisms to ethylbenzene.
Changes in the integrity of the cell membrane after partitioning of ethylbenzene into the lipid bilayer may subsequently affect the function of membrane, particularly as a barrier and in energy transduction, and in the formation of a matrix for proteins and enzymes. Ethybenzene inhibits the activity of the astrocytic membrane ATPases, which helps regulate adequate intercellular levels of ions, nutrients, metabolic intermediates and precursors in the central nervous system. Thus, this may disturb the ability of the cells to maintain homeostasis. (L311, A186)
CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: nonclassifiable due to lack of animal bioassays and human studies. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: None. NTP has plans to initiate bioassay. Metabolism and excretion studies at 3.5, 35 and 350 mg/kg are to be conducted as well.
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌性证据
A3; 已确认的动物致癌物,对人类的相关性未知。
A3; Confirmed animal carcinogen with unknown relevance to humans.
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌物分类
国际癌症研究机构致癌物:乙苯
IARC Carcinogenic Agent:Ethylbenzene
来源:International Agency for Research on Cancer (IARC)
吸收、分配和排泄
人类暴露于乙苯主要是通过吸入;吸入的乙苯中有40-60%留在肺部。
Human exposure to ethylbenzene occurs mainly by inhalation; 40-60% of inhaled ethylbenzene is retained in the lung.
Three lab technicians exposed to 42 ppm & 1 to 34 ppm had avg steady state blood levels of 0.72 + or - 0.11 mg/L. 30 Min after exposure concn had dropped to approx 0.5% of original values.
When administered sc to 40 rats (2.5 ml, 1:1 v/v), ethylbenzene was detected in the blood within 2 hours, and the levels of ethylbenzene (10-15 ppm in blood) were maintained for at least 16 hours.
Organocerium additions to proline-derived hydrazones: synthesis of enantiomerically enriched amines
作者:Scott E. Denmark、James P. Edwards、Theodor Weber、David W. Piotrowski
DOI:10.1016/j.tetasy.2010.04.042
日期:2010.5
The addition of organocerium reagents (from both organolithium and organomagnesium precursors) to chiral aldehyde hydrazones prepared from 1-aminoproline derivatives has been studied. The additions proceed in good yield and high diastereoselectivity and with good nucleophile (Me, n-Bu, i-Pr, t-Bu, Ph, etc.) and substrate scope (alkyl, alkenyl and aryl). The resulting hydrazines can be converted to
Copper-Catalyzed Protodecarboxylation of Aromatic Carboxylic Acids
作者:Lukas J. Gooßen、Werner R. Thiel、Nuria Rodríguez、Christophe Linder、Bettina Melzer
DOI:10.1002/adsc.200700223
日期:2007.10.8
A catalyst generated from copper(I) oxide and 4,7-diphenyl-1,10-phenanthroline for the first time allows the catalytic protodecarboxylation even of deactivated aromatic carboxylic acids, giving rise to the corresponding arenes. Based on DFT calculations, a reaction pathway is proposed that accurately reflects the experimental results, such as the observed reactivity order of the substrates.
Process for producing 3-amino-2-oxo-1-halogenopropane derivatives
申请人:Ajinomoto Co., Inc.
公开号:US05767316A1
公开(公告)日:1998-06-16
Compounds formed by reacting a protected amino acid with an alkali metal enolate of an alkyl acetate are reacted with a halogenating agent for halogenation of the 2-position, or a protected amino acid is reacted with an alkali metal enolate of an alkyl halogenoacetate, to form a 4-amino-3-oxo-2-halogenobutanoic acid ester derivative, and hydrolysis and decarboxylation are conducted to produce a 3-amino-2-oxo-1-halogenopropane derivative or its salt. The present method is a useful process for producing a 3-amino-2-oxo-1-halogenopropane derivatives which can easily be converted to a 3-amino-1,2-epoxypropane.
Reversible Silylium Transfer between P‐H and Si‐H Donors
作者:Roman G. Belli、Dimitrios A. Pantazis、Robert McDonald、Lisa Rosenberg
DOI:10.1002/anie.202011372
日期:2021.2
The Mo=PR2 π* orbital in a Mo phosphenium complex acts as acceptor in a new PIII‐based Lewis superacid. This Lewisacid (LA) participates in electrophilic Si‐H abstraction from E3SiH to give a Mo‐bound secondary phosphine ligand, Mo‐PR2H. The resulting Et3Si+ ion remains associated with the Mo complex, stabilized by η1‐P‐H donation, yet undergoes rapid exchange with an η1‐Si‐H adduct of free silane in
Facile Regio- and Stereoselective Hydrometalation of Alkynes with a Combination of Carboxylic Acids and Group 10 Transition Metal Complexes: Selective Hydrogenation of Alkynes with Formic Acid
作者:Ruwei Shen、Tieqiao Chen、Yalei Zhao、Renhua Qiu、Yongbo Zhou、Shuangfeng Yin、Xiangbo Wang、Midori Goto、Li-Biao Han
DOI:10.1021/ja2069246
日期:2011.10.26
highly stereo- and regioselective hydrometalation of alkynes generating alkenylmetal complex is disclosed for the first time from a reaction of alkyne, carboxylic acid, and a zerovalent group10 transition metal complex M(PEt(3))(4) (M = Ni, Pd, Pt). A mechanistic study showed that the hydrometalation does not proceed via the reaction of alkyne with a hydridometal generated by the protonation of a