ChemicalBook > Product Catalog > Organic Chemistry > Hydrocarbons and derivatives > Aromatic hydrocarbons > m-Xylene
m-Xylene Chemical Properties
- Melting point:-48 °C
- Boiling point:139 °C
- Density 0.868 g/mL at 25 °C(lit.)
- vapor density 3.7 (vs air)
- vapor pressure 16 mm Hg ( 37.7 °C)
- refractive index n
- Flash point:77 °F
- storage temp. 0-6°C
- solubility Miscible with many organic solvents, including alcohol and ether
- form Liquid
- pka>15 (Christensen et al., 1975)
- color Colorless
- OdorLike benzene; characteristic aromatic.
- Odor Threshold0.041ppm
- explosive limit1.1-7%(V)
- Water Solubility Miscible with organic solvents. Immiscible with water.
- Merck 14,10081
- BRN 605441
- Henry's Law Constant14.80 at 45.00 °C, 17.26.4 at 50.00 °C, 19.90 at 55.00 °C, 23.01.3 at 60.00 °C, 27.46.3 at 70.00 °C (static headspace-GC, Park et al., 2004)
- Exposure limitsNIOSH REL: 100 ppm (435 mg/m3), STEL 150 ppm (655 mg/m3), IDLH 900 ppm; OSHA PEL: TWA 100 ppm; ACGIH TLV: TWA 100 ppm, STEL 150 ppm (adopted).
- CAS DataBase Reference108-38-3(CAS DataBase Reference)
- NIST Chemistry ReferenceBenzene, 1,3-dimethyl-(108-38-3)
- EPA Substance Registry Systemm-Xylene (108-38-3)
- Hazard Codes Xn,T,F
- Risk Statements 10-20/21-38-39/23/24/25-23/24/25-11-36/38
- Safety Statements 25-45-36/37-16-7
- RIDADR UN 1307 3/PG 3
- WGK Germany 2
- RTECS ZE2275000
- Autoignition Temperature982 °F
- TSCA Yes
- HazardClass 3
- PackingGroup II
- HS Code 29024200
- Hazardous Substances Data108-38-3(Hazardous Substances Data)
- ToxicityLD50 orally in rats: 7.71 ml/kg (Smyth)
m-Xylene Usage And Synthesis
- Chemical Propertiesclear colourless liquid
- Chemical PropertiesXylene exists in three isomeric forms, ortho-, meta-, and para-xylene. Commercial xylene is a mixture of these three isomers and may also contain ethylbenzene as well as small amounts of toluene, trimethylbenzene, phenol, thiophene, pyridine, and other nonaromatic hydrocarbons. m-Xylene is predominant in commercial xylene.
- Physical propertiesClear, colorless, watery liquid with a sweet, aromatic odor. An odor threshold concentration of 48 ppbv was reported by Nagata and Takeuchi (1990).
- UsesMeta-Xylene is used for the production of isophthalic acid, of agriculture chemicals as pharmaceuticals. It finds applications in paint and varnish removers and aerosol paint concentrates. Product Data Sheet
- DefinitionChEBI: A xylene carrying methyl groups at positions 1 and 3.
- General DescriptionA colorless watery liquid with a sweet odor. Less dense than water. Insoluble in water. Irritating vapor.
- Air & Water ReactionsHighly flammable. Insoluble in water.
- Reactivity Profilem-Xylene may react with oxidizing materials. .
- Health HazardVapors cause headache and dizziness. Liquid irritates eyes and skin. If taken into lungs, causes severe coughing, distress, and rapidly developing pulmonary edema. If ingested, causes nausea, vomiting, cramps, headache, and coma; can be fatal. Kidney and liver damage can occur.
- Fire HazardBehavior in Fire: Vapor is heavier than air and may travel considerable distance to a source of ignition and flash back.
- Chemical ReactivityReactivity with Water No reaction; Reactivity with Common Materials: No reaction; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
- Safety ProfileModerately toxic by intraperitoneal route. Wdly toxic by ingestion, skin contact, and inhalation. An experimental teratogen. Human systemic effects by inhalation: motor activity changes, ataxia, and irritabihty. Experimental reproductive effects. A severe skin irritant. A common air contaminant. A very dangerous fire hazard when exposed to heat or flame; can react with oxidzing materials. Explosive in the form of vapor when exposed to heat or flame. To fight fire, use foam, CO2, dry chemical. Emitted from modern building materials (CENEAR 69,22,91). When heated to decomposition it emits acrid smoke and irritating fumes. See also other xylene entries.
- Potential ExposureXylene is used as a solvent; as a constituent of paint, lacquers, varnishes, inks, dyes, adhesives, cements, cleaning fluids, and aviation fuels; and as a chemical feed-stock for xylidines, benzoic acid; phthalic anhydride; isophthalic, and terephthalic acids; as well as their esters (which are specifically used in the manufacture of plastic materials and synthetic textile fabrics). Xylene is also used in the manufacture of quartz crystal oscillators, hydrogen peroxide; perfumes, insect repellants; epoxy resins; pharmaceuticals; and in the leather industry. m-Xylene is used as an intermediate in preparation of isophthalic acid; o-xylene is used in manufacture of phthalic anhydride and in pharmaceutical and insecticide synthesis. p-xylene is used in pharmaceutical and insecticide synthesis and in production of polyester.
- SourceAs m+p-xylene, detected in distilled water-soluble fractions of 87 octane gasoline, 94
octane gasoline, and Gasohol at concentrations of 7.00, 20.1, and 14.6 mg/L, respectively (Potter,
1996); in distilled water-soluble fractions of new and used motor oil at concentrations of 0.26 to
0.29 and 302 to 339 μg/L, respectively (Chen et al., 1994). The average volume percent and
estimated mole fraction in American Petroleum Institute PS-6 gasoline are 4.072 and 0.04406,
respectively (Poulsen et al., 1992). Diesel fuel obtained from a service station in Schlieren,
Switzerland contained m/p-xylene at a concentration of 336 mg/L (Schluep et al., 2001).
Thomas and Delfino (1991) equilibrated contaminant-free groundwater collected from Gainesville, FL with individual fractions of three individual petroleum products at 24–25 °C for 24 h. The aqueous phase was analyzed for organic compounds via U.S. EPA approved test method 602. Average m+p-xylene concentrations reported in water-soluble fractions of unleaded gasoline, kerosene, and diesel fuel were 8.611, 0.658, and 0.228 mg/L, respectively. When the authors analyzed the aqueous-phase via U.S. EPA approved test method 610, average m+p-xylene concentrations in water-soluble fractions of unleaded gasoline, kerosene, and diesel fuel were lower, i.e., 6.068, 0.360, and 0.222 mg/L, respectively.
Based on laboratory analysis of 7 coal tar samples, m+p-xylene concentrations ranged from ND to 6,000 ppm (EPRI, 1990). A high-temperature coal tar contained m-xylene at an average concentration of 0.07 wt % (McNeil, 1983).
Schauer et al. (2001) measured organic compound emission rates for volatile organic compounds, gas-phase semi-volatile organic compounds, and particle-phase organic compounds from the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission rate of m-xylene + p-xylene was 60.0 mg/kg of pine burned. Emission rates of both isomers were not measured during the combustion of oak and eucalyptus.
Drinking water standard (final): For all xylenes, the MCLG and MCL are both 10 mg/L. In addition, a DWEL of 70 mg/L was recommended (U.S. EPA, 2000).
- Environmental FateBiological. Microbial degradation produced 3-methylbenzyl alcohol, 3-methylbenzaldehyde, mtoluic
acid, and 3-methylcatechol (quoted, Verschueren, 1983). m-Toluic acid was reported to be
the biooxidation product of m-xylene by Nocardia corallina V-49 using n-hexadecane as the
substrate (Keck et al., 1989). Reported biodegradation products of the commercial product
containing xylene include α-hydroxy-p-toluic acid, p-methylbenzyl alcohol, benzyl alcohol, 4-
methylcatechol, m- and p-toluic acids (Fishbein, 1985). In anoxic groundwater near Bemidji, MI,
m-xylene anaerobically biodegraded to the intermediate m-toluic acid (Cozzarelli et al., 1990). In
gasoline-contaminated groundwater, methylbenzylsuccinic acid was identified as the first
intermediate during the anaerobic degradation of xylenes (Reusser and Field, 2002).
Photolytic. When synthetic air containing gaseous nitrous acid and m-xylene was exposed to artificial sunlight (λ = 300–450 nm) biacetyl, peroxyacetal nitrate, and methyl nitrate were formed (Cox et al., 1980). They reported a rate constant of 1.86 x 10-11 cm3/molecule?sec for the reaction of gaseous m-xylene with OH radicals based on a value of 8 x 10-12 cm3/molecule?sec for the reaction of ethylene with OH radicals.
Chemical/Physical. Under atmospheric conditions, the gas-phase reaction with OH radicals and nitrogen oxides resulted in the formation of m-tolualdehyde, m-methylbenzyl nitrate, nitro- mxylenes, 2,4- and 2,6-dimethylphenol (Atkinson, 1990). Kanno et al. (1982) studied the aqueous reaction of m-xylene and other aromatic hydrocarbons (benzene, toluene, o- and p-xylene, and naphthalene) with hypochlorous acid in the presence of ammonium ion. They reported that the aromatic ring was not chlorinated as expected but was cleaved by chloramine forming cyanogen chloride. The amount of cyanogen chloride formed increased at lower pHs (Kanno et al., 1982). In the gas phase, m-xylene reacted with nitrate radicals in purified air forming pmethylbenzaldehyde, an aryl nitrate and trace amounts of 2,6-dimethylnitrobenzene, 2,4- dimethylnitrobenzene, and 3,5-dimethylnitrobenzene (Chiodini et al., 1993).
- ShippingUN1307 Xylenes, Hazard Class: 3; Labels: 3-Flammable liquid.
- Purification MethodsThe general purification methods listed under xylene are applicable. The o-and p-isomers can be removed by their selective oxidation when a m-xylene sample containing them is boiled with dilute HNO3 (one part conc acid to three parts water). After washing with water and alkali, the product can be steam distilled, collected as for o-xylene, then distilled and purified further by sulfonation. [Clarke & Taylor J Am Chem Soc 45 831 1923.] m-Xylene is selectively sulfonated when a mixture of xylenes is refluxed with the theoretical amount of 50-70% H2SO4 at 85-95o under reduced pressure. By using a still resembling a Dean and Stark apparatus, water in the condensate can be progressively withdrawn while the xylene is returned to the reaction vessel. After cooling, then adding water, unreacted xylenes are distilled off under reduced pressure. The m-xylene sulfonic acid is subsequently hydrolysed by steam distillation up to 140o, the free m-xylene is washed, dried with silica gel and again distilled. It is stored over molecular sieves Linde type 4A. [Beilstein 5 H 370, 5 I 182, 5 II 287, 5 III 823, 5 IV 932.]
- IncompatibilitiesVapor 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, and epoxides. Electrostatic charges can be generated from agitation or flow.
- Waste DisposalConsult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal. Incineration.
m-Xylene Preparation Products And Raw materials
- Preparation ProductsP-XYLENE1,2-Dimethylbenzene2,6-DimethylanilineMetalaxylIsophthalic acidAmitraz4-BROMO-3-METHYLBENZAMIDEChlorothalonil1,2,4,5-Benzenetetracarboxylic anhydride1,2,4,5-Tetramethylbenzene1,3-Dicyanobenzenem-Toluic acid2,4-Dimethyl anilineMusk xyleneAMITRAZ METABOLITE HYDROCHLORIDE4-TERT-BUTYL-2,6-DIMETHYL BENZYL ACETATE1,4-BIS(TRICHLOROMETHYL)BENZENE2-(Dimethylamino)ethyl (4-chlorphenoxy)acetateMusk ketone4-Nitro-1,3-dimethylbenzene5-TERT-BUTYL-M-XYLENE2,6-Dicyano-4-Nitroaniline2,6-Dimethyl-1-nitrobenzene3,5-Dimethylphenol4-tert-butyl-3-hydroxy-2,6-xylylacetonitrile Diphenyl isophthalate4-Tert-butyl-2,6-dimethylbenzylchloroide 2',4'-Dimethylacetophenone1,3-Bis(trifluoromethyl)-benzeneISOCYANATO(METHOXY)METHANE3-Methylbenzyl chloride2,4-Dimethylphenol
- Raw materialsHydrogenXyleneP-XYLENECOAL TARY type molecular sieveAdsorbent
- DIMETHYLBENZENE,Dimethylbenzene(mixture 5-BROMO-2-ISOCYANO-1,3-DIMETHYLBENZENE 5-NITRO-M-XYLENE-ALPHA,ALPHA'-DIOL 1-(1-chloroethyl)-2,3-dimethylbenzene 5-BROMO-3,5-DIMETHYLBENZENE,5-BROMO-M-XYLENE 3,5-Bis(trifluoromethyl)phenol 3'-(Trifluoromethyl)acetophenone 3,5-Bis(trifluoromethyl)benzoyl chloride 1-BROMO-2,3,5,6-TETRAMETHYLBENZENE 2,4,6-Trimethybromombenzene 3,3'-BIS(TRIFLUOROMETHYL)BENZOPHENONE 3-(TRIFLUOROMETHYL)BENZOPHENONE 3,5-Bis(trifluoromethyl)benzoic acid A,A,A,A',A',A'-HEXAFLUORO-M-XYLENE 3,5-Bis(trifluoromethyl)benzonitrile 2,5-Bis(trifluoromethyl)nitrobenzene 2,6-BIS(TRIFLUOROMETHYL)BENZOIC ACID 3,5-Bis(trifluoromethyl)bromobenzene
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