m-Cresol

m-Cresol - Names and Identifiers

Name	m-Cresol
Synonyms	m-Cresol M-CRESOL FEMA 3530 m-Cresole 3-Cresol M-CRESOL 70 META-CRESOL Meta-Cresol m-methylphenol 3-Methylphenol 3-methyl-Phenol 3-Hydroxytoluene hydroxy-3-methylbenzene Hydroxy-3-methylbenzene 1-hydroxy-3-methylbenzene
CAS	108-39-4
EINECS	203-577-9

m-Cresol - Physico-chemical Properties

Molecular Formula	C7H8O
Molar Mass	108.14
Density	1.034g/mLat 25°C(lit.)
Melting Point	8-10°C(lit.)
Boling Point	203°C(lit.)
Flash Point	187°F
JECFA Number	692
Water Solubility	20 g/L (20 ºC)
Solubility	23.5g/l
Vapor Presure	<1 mm Hg ( 20 °C)
Vapor Density	3.72 (vs air)
Appearance	Liquid
Color	Clear colorless to slight red
Exposure Limit	ACGIH: TWA 20 mg/m3 (Skin)NIOSH: IDLH 250 ppm; TWA 2.3 ppm(10 mg/m3)
Maximum wavelength(λmax)	['273nm(lit.)']
Merck	14,2579
BRN	506719
pKa	10.01(at 25℃)
PH	5 (20g/l, H2O, 20℃)
Storage Condition	Store below +30°C.
Stability	Stable. Combustible. Incompatible with strong oxidizing agents, strong bases, strong acids, aluminium, aluminium alloys. Air and light sensitive. Hygroscopic.
Explosive Limit	1.06-1.35%, 150°F
Refractive Index	n20/D 1.541(lit.)
Physical and Chemical Properties	Colorless or light yellow flammable liquid. There is a smell of phenol. solubility is about 40 times greater in water (2.5% at 40 °c and 100 at 5.5% °c). Soluble in caustic and commonly used organic solvents.
Use	Mainly used in pesticides, pharmaceuticals, spices, resin plasticizers, film, antioxidants, and reagents and so on all need to use m-cresol chemical industry.

m-Cresol - Risk and Safety

Hazard Symbols	T - Toxic
Risk Codes	R24/25 - R34 - Causes burns R39/23/24/25 - R23/24/25 - Toxic by inhalation, in contact with skin and if swallowed.
Safety Description	S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S36/37 - Wear suitable protective clothing and gloves.
UN IDs	UN 2076 6.1/PG 2
WGK Germany	1
RTECS	GO6125000
FLUKA BRAND F CODES	8
TSCA	Yes
HS Code	29071200
Hazard Class	6.1
Packing Group	II
Toxicity	LD50 orally in rats: 2.02 g/kg (Deichmann, Witherup)

m-Cresol - Reference Information

Open Data Unverified Data

FEMA	3530 \| M-CRESOL
olfactory Threshold	0.0001ppm
LogP	1.96
NIST chemical information	information provided by: webbook.nist.gov (external link)
EPA chemical substance information	information provided by: ofmpeb.epa.gov (external link)
toxicity	is toxic to the central nervous system and can cause death in severe cases. Ld502020 mg/kg (rat, oral). GRAS(FEMA).
usage limit	FEMA(mg/kg): baked food 1.0; Meat products, soup products, snack foods, nut products, instant coffee, instant tea, spices, meat juice, 0.5.
Use	used as a dye intermediate for color film, used in the production of pesticides such as dexamethasone, benthio, methacryl, permethrin, and resins, plasticizers, etc. used as analytical reagents and intermediates in organic synthesis GB 2760-1996 is a permitted flavor. It is mainly used as an intermediate of pesticide, producing pesticides such as trimethoprim, trimethoprim, methacryl, and permethrin. It is also an intermediate of color film, resin, plasticizer and perfume. m-cresol, also known as m-cresol, is mainly used as a pesticide intermediate in the production of insecticides, such as insecticide, fenthiophos, fenthiophos, methacryl and pyrethroid alcohol moiety, such as M-phenoxybenzaldehyde. mainly used in pesticides, pharmaceuticals, spices, resin plasticizers, film, antioxidants, and reagents and so on all need to use m-cresol chemical industry. used as analytical reagent and in organic synthesis analytical reagent. Organic Synthesis. Fungicide. Fungicide. Developer.
production method	before the 50 s of the 20th century, the main source of m-cresol was recovered from coking by-product coal tar and alkaline residue of petroleum refining, but the amount of recovery is very small, can not meet the needs of industry. After the development of the synthesis of m-cresol, the process has two routes: one is toluene as raw material, by sulfonated alkali fusion synthesis; The other is isopropyl toluene method, co-production of acetone. In the early 90 s of the 20th century, China introduced this technology from the United States, and the device was put into operation in Beijing Yanshan. In addition to the production of 12,000 tons/year of main product m-cresol, this unit also produces 9,900 tons of acetone. Compared with other methods, the product produced by this device is of high quality and the product proportion can be freely adjusted. Toluene sulfonation alkali fusion method from toluene and sulfuric acid (98%) reaction (100~110 ℃), and then heated to 150 ℃, continue to add toluene, then heated to 190 ℃ for isomerization, finally, the alkali is melted to give cresol. Its composition is as follows: phenol 3.1%, P-cresol 37.4%, O-cresol 4.7%, m-cresol 54.8%. The m-and p-cresol obtained by the above reaction is redistilled with a high-efficiency distillation column, Cut a narrow fraction at 201~208 ℃ to obtain a mixture of m-cresol and p-cresol, etc. Dilute the material with benzene, add urea, react at -10 ℃ for 1H, centrifuge and filter with suction, washing twice with benzene or toluene at -10 °c gave a white solid complex of m-cresol-urea. Then the complex is hydrolyzed with toluene at 15~80 ° C., the upper liquid layer is taken, and toluene and water are distilled off at normal pressure in the rectification column, the fraction of 91-0.1 ° C. Was cut under a vacuum of 104 MPa to obtain m-cresol with a content of 95% or more. This method is the earliest industrialized method, and the process route is mature. This method was used in the early production abroad. However, due to the consumption of a large amount of acid and alkali, the three wastes are large, the equipment is seriously corroded, and the solid materials need to be treated many times in the process, so that the continuous production is difficult, and the quality is poor, the economy is not as good as the isopropyl toluene method. Isopropyltoluene method toluene as raw material, in the presence of a catalyst with propylene alkylation reaction, and then through oxidation, acid hydrolysis obtained. The reaction equation is shown in Fig. Alkylation alkylation with aluminum chloride as catalyst (the amount of 1%~ 2%), reaction temperature 85~115 ℃, propylene/toluene = 0.4~0.6(mol), under these conditions, the meta-isomer with high yield can be obtained. Oxidation the oxidizing agent used for the oxidation of isopropyl toluene is air, pure oxygen or hydrogen peroxide, and it is generally economical to oxidize by air. The oxidation reaction is carried out in the presence of an initiator (benzoyl peroxide or azobisisobutyronitrile), the amount of which is about 1% of the mass of isopropyl toluene, the reaction temperature is 138~140 ℃, and the reaction time is 130~150 min, the ventilation amount is 5% excess according to the theory; The pH value of the reaction solution is controlled at about 5, and the oxidation depth is controlled at 15%. Under these conditions, the total isopropyl toluene hydroperoxide is about 85%-90%. Decomposition of isopropyl toluene hydrogen peroxide in the presence of sulfuric acid decomposition of cresol and acetone. The mixed cresol synthesized by this method is about 6 ∶ 4 for m-and p-diisomers, and the composition of the decomposition liquid after acid decomposition is about 34.2% for acetone, 30.7% for m-and p-mixed cresol, and 6.9% for isopropyl toluene, Α-methylstyrene 3.9%, peroxide 4.4%. Separation and Purification of O-cresol and Inter, P-cresol boiling point difference is larger, select the appropriate equipment can be separated, but m-cresol (202.9 ℃) and p-Cresol (202.5 ℃) boiling point is very close, can not be separated by fractionation. Using isobutylene alkylation method can get good results, the process is: mixed cresol in the presence of catalyst with isobutylene alkylation, get di-tert-butyl m-cresol and di-tert-butyl p-cresol mixture. The product obtained by tert-butylation of cresol is a complex mixture in which there are unreacted polymers of cresol and isobutylene in addition to the mono-tert-butyl cresol isomer and di-tert-butyl isomer, it can be separated by distillation. 4, 6-di-tert-butyl-m-cresol obtained after separation, When heated to 202 ℃ in the presence of catalyst, m-cresol and isobutylene can be decomposed into m-cresol. The content of m-cresol is over 98% and the recovery rate is about 95%. Isobutene recovery rate of more than 95%, can be recycled. This method can be used to separate m-cresol and produce 2, 6-di-tert-butyl-p-cresol antioxidant. The synthesis method is mainly used abroad, and it can also be separated from mixed cresol, a by-product of coking, oil shale retorting and city gas. M-and p-cresol can be separated by azeotropic method, urea method, dissociated benzene extraction method, sulfonated hydrolysis method, phenol crystallization method, alkylation method and other methods. 1. Toluene and propylene in the role of aluminum chloride to generate isopropyl toluene, and then by air oxidation of hydrogen peroxide isopropyl toluene, the latter by acid hydrolysis into acetone and meta-and para-mixed cresol. After the reaction of mixed cresol and isobutylene, the reaction product is separated by distillation according to the characteristics of the boiling point difference between the reaction products and the p-cresol alkylate, and then the tert-butyl group is removed to obtain pure m-cresol. O-Xylene is oxidized to O-Toluic acid by air under the catalysis of cobalt naphthenate, and then the O-Toluic acid is converted to m-cresol by oxidative decarboxylation with copper oxide and magnesium oxide as catalyst. isopropyl toluene was formed from toluene and propylene in the presence of aluminum trichloride, which was oxidized by air to form isopropyl toluene hydroperoxide. After acid hydrolysis, acetone and m-and p-mixed cresol were obtained. Mixed cresol and isobutylene reaction after distillation separation, and then remove the tert-butyl group.
category	corrosive article
toxicity grade	high toxicity
Acute toxicity	oral-rat LD50: 242 mg/kg; Oral-mouse LD50: 828 mg/kg
stimulation data	Skin-rabbits 517 mg/24 h severe; eye-rabbit 103 mg severe
explosive hazard characteristics	explosive when mixed with air; Corrosive to skin and cornea
flammability hazard characteristics	flammable; Combustion-induced irritating smoke
storage and transportation characteristics	The warehouse is ventilated and dried at low temperature; It is stored separately from the oxidant.
fire extinguishing agent	Sand, foam, water mist
Occupational Standard	TLV-TWA 5 PPM (22 mg/m3)
spontaneous combustion temperature	626°C
toxic substance data	information provided by: pubchem.ncbi.nlm.nih.gov (external link)