METHYL MERCAPTAN
Methyl Mercaptan
CAS: 74-93-1
Molecular Formula: CH4S
METHYL MERCAPTAN - Names and Identifiers
| Name | Methyl Mercaptan |
| Synonyms | Methvtiolo Methanthiol methanethiol Thiomethanol Methanethiole Metilmercaptano Mercaptomethane Methyl Mercaptan Methylmercaptaan Methyl mercaptain Methylthioalcohol methylthioalcohol Methyl Sulfhydrate Methyl thioalcohol Methanethiol-SD (gas) mercury dimethanethiolate |
| CAS | 74-93-1 |
| EINECS | 200-822-1 |
| InChI | InChI=1/2CH4S.Hg/c2*1-2;/h2*2H,1H3;/q;;+2/p-2 |
METHYL MERCAPTAN - Physico-chemical Properties
| Molecular Formula | CH4S |
| Molar Mass | 48.11 |
| Density | 0.8665 |
| Melting Point | −123°C(lit.) |
| Boling Point | 6°C(lit.) |
| Flash Point | <71℃ |
| JECFA Number | 508 |
| Water Solubility | 23.30 g/L at 20 °C (quoted, Windholz et al., 1983)0.330 mol/L at 25 °C (Hine and Weimar, 1965) |
| Solubility | Soluble in alcohol, ether (Weast, 1986), and petroleum naphtha (Hawley, 1981) |
| Vapor Presure | 1536 mm Hg ( 20 °C) |
| Vapor Density | 1.66 (vs air) |
| Appearance | liquid |
| Exposure Limit | TLV-TWA 0.5 ppm (～1.0 mg/m3 ) (ACGIHand MSHA); ceiling 10 ppm (OSHA); IDLH400 ppm (NIOSH); the revised IDLH is 150ppm in analogy to H2S. |
| Merck | 13,5983 |
| BRN | 1696840 |
| pKa | 10.3(at 25℃) |
| Stability | Stable. Highly flammable - note low flash point. Reacts vigorously or explosively with a wide variety of materials - consult a full MSDS data sheet before using. Incompatible with strong oxidizing age |
| Explosive Limit | 21.8% |
| Refractive Index | 1.4020 (estimate) |
| Physical and Chemical Properties | Character: colorless flammable gas at normal temperature, colorless liquid at low temperature, with unpleasant odor. melting point -121 ~-123 ℃ boiling point 5.9 ℃ relative density 0.8665 flash point <71 ℃ solubility slightly soluble in water. Soluble in alcohol, ether, petroleum ether, etc. |
| Use | Used as intermediates in organic synthesis, mainly used in the synthesis of materials, pesticides and pharmaceuticals |
METHYL MERCAPTAN - Risk and Safety
| Risk Codes | R12 - Extremely Flammable R23 - Toxic by inhalation R50/53 - Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. |
| Safety Description | S16 - Keep away from sources of ignition. S25 - Avoid contact with eyes. S60 - This material and its container must be disposed of as hazardous waste. S61 - Avoid release to the environment. Refer to special instructions / safety data sheets. |
| UN IDs | UN 2037 2.3 |
| WGK Germany | 3 |
| RTECS | PB4375000 |
| FLUKA BRAND F CODES | 13-27 |
| Hazard Class | 2.3 |
| Toxicity | LC50 (inhalation) for mice 6,530 μg/m3/2-h, rats 675 ppm (quoted, RTECS, 1985). |
METHYL MERCAPTAN - Upstream Downstream Industry
| Downstream Products | 3-(Methylthio)butyraldehyde Ethyl 3-methylthiopropionate Methyl thiofuroate |
METHYL MERCAPTAN - Reference Information
Open Data Unverified Data
| FEMA | 2716 | METHYL MERCAPTAN |
| olfactory Threshold | 0.00007ppm |
| Henry's Law Constant | 3.03 (Hine and Weimar, 1965) |
| EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
| mercaptans | methyl mercaptan is a kind of mercaptan compounds, mercaptan is the sulfur atom to replace the oxygen atom of hydroxyl group, on the other hand, the compounds having a hydrothio group [-SH](mercapto group) include Aliphatic thiols and aromatic thiols. thiol compounds are generally malodorous and have hypnotic effects. High concentration can paralyze the central nerve; When used locally, it can cause conjunctival and corneal opacity, etc., showing the same symptoms as hydrogen sulfide. Therefore, attention should be paid to its toxicity and environmental pollution. methyl mercaptan belongs to Aliphatic thiols. In protein corruption caused by bacteria, cysteine is decomposed into an intermediate product of hydrogen sulfide process, and the main use is feed additive as a raw material of an essential amino acid methionine. methyl mercaptan can be used for the preparation of methionine, lysine and tryptophan; Pesticide raw materials, the preparation of herbicides and insecticides "trithiophos", "permethrin", "trimethophos", "Pu Cao Jing", etc.; Spices and wool dyeing auxiliary raw materials, preparation of chlorosulfonyl, methanesulfonyl chloride raw materials, methanesulfonyl chloride used as polymerization catalyst, dehydrating agent, electroplating agent, corrosion inhibitor, etherification accelerator, chlorosulfonyl used as etherification and polymerization catalyst, stabilizer of liquid SO3, drying oil curing accelerator, reaction with amino group and hydroxyl group, can be used as the introduction of methyl sulfonyl agent; Gas odorant; spices, methyl mercaptan is our country GB2760-1996 regulations allow the use of edible spices. |
| hazardous | (1) methyl mercaptan is toxic and highly irritating. (2) flammable, there is a greater risk of combustion, can form an explosive mixture with air, the explosion limit of 3.9 ~ 21.8%. The allowable concentration in air is 0.5ppm (1mg/m3) in the United States. |
| adverse effects and toxic symptoms | inhalation of high concentration poisoning will cause anesthesia, accompanied by cyanosis, spasm, Head Pain, Nausea, etc.; Can stimulate the lungs; Heavy can make lung injury, even respiratory paralysis. |
| first aid | if this chemical enters the eyes, rinse with water immediately; If it contacts the skin, wash with water immediately; if there is a large number of inhalation, immediately move away from the scene, breathing fresh air, if necessary, artificial respiration. Or ask a doctor for treatment. |
| Protection Measure | proper work clothes should be worn to prevent frostbite. Wear protective glasses to prevent eye contact. If the work clothes are wet or contaminated, take them off immediately to avoid the risk of burning. |
| storage | cylinder. Anti-collision is required when placing the cylinder. Stored in a cool, well-ventilated place, it is best to use the open air or attached warehouse, away from the fire prone place. Separated from the oxidizing agent. |
| toxicity | high concentration vapor has anesthetic effect. Mass entry into the body can lead to liver damage. It is safe for use in food as a flavor (FDA,§ 172.515,2000). GRAS(FEMA). |
| usage limit | FEMA(mg/kg): Soft drink 0.56; Cold drink 0.13~1.0; Candy 0.13~1.0; baking food 0.15~1.0. |
| Application | methanethiol is an insecticide, methomyl, aldicarb, chlorathion, peroxyverine, vermacarb, thiodimethomyl and the intermediate of herbicide xiachao net, chlorphenamine net, atractylodine net, diphenoxylate net, Terbutaline and the like can also be used to produce medical methionine. GB 2760-1996 provides for the permitted use of flavorants. organic synthetic raw materials, can be used for the synthesis of dyes, pesticides, pharmaceuticals, such as methionine, trimethophos, permethrin, trimethoprim, etc., also used for the production of methanesulfonyl chloride, intermediates such as methylthiopropanol. used as organic synthesis intermediates, mainly used in synthetic materials, pesticides and pharmaceuticals, etc. |
| production method | gas phase synthesis of methanol and hydrogen sulfide using activated alumina as the main catalyst, reaction temperature 280-450 ℃, reaction pressure 0.74-0.25MPa. Methyl mercaptan is produced by this method, and the recovery rate based on methanol can exceed 64-70%. The process for producing mercaptans using halogenated hydrocarbons and hydrosulfates (or thiourea), olefins and hydrogen sulfide can also be used in industry. In smaller scale production, the reaction of thiourea with dimethyl sulfate followed by hydrolysis by the addition of a base may be employed. Water was added to the reaction Pan, thiourea was added with stirring, and dimethyl sulfate was added dropwise. When the temperature naturally increased to 80-90 °c, it was heated to 120 °c and reacted until the material was viscous. Methyl thiurate filter cake was obtained by discharging and cooling, and then the temperature was controlled to 50-60 ° C., sodium hydroxide solution was added dropwise to methylisothiourea sulfate to generate methyl mercaptan. The main catalyst is activated alumina, which is derived from the gas phase reaction of methanol and hydrogen sulfide at 280~450 ℃,0.74 ~ 0.25MPa. The preparation method is to put water and thiourea into the reaction kettle, Dropwise add dimethyl sulfate, when the temperature naturally rises to 80~90 ℃, start heating to 116~120 ℃, reaction 30~40min, discharge, cooling, centrifugation, The obtained filter cake was methylisothiourea sulfate, and then the alkali solution was added dropwise to methylisothiourea sulfate at 80 ° C., and methanethiol was continuously produced. Methyl mercaptan can also be obtained by reacting methyl chloride and sodium hydrosulfide. 36% sodium hydrosulfide is added into the autoclave, methyl chloride is injected with nitrogen, and stirring is started. The temperature is controlled not to exceed 100 ℃ and the pressure is not higher than 1.7 MPa, reaction for 30 min, when the temperature and pressure drop to moderate, open the pressure valve, control the pressure and flow, after washing and absorption to get sodium methyl mercaptan. CH3Cl + NaHS [pressure] → CH3SH + NaClCH3SH + NaOH → CH3SNa + H2O |
| category | flammable liquid |
| toxicity grade | high toxicity |
| Acute toxicity | inhalation-rat LC50: 675 PPM; inhalation-mouse 6.53 mg/m3/2 h |
| explosive hazard characteristics | explosive when mixed with air |
| flammability hazard characteristics | in case of open flame, high temperature, flammable oxidant; Combustion produces toxic sulfur oxide smoke; In contact with water, toxic and flammable hydrogen sulfide gas produced by acid |
| storage and transportation characteristics | The warehouse is ventilated and dried at low temperature; Stored separately from oxidants and acids |
| extinguishing agent | dry powder, dry sand, carbon dioxide, foam, 1211 extinguishing agent |
| Occupational Standard | TWA 1 mg/m3 |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
| immediate life-and health-threatening concentration | 150 ppm |
Last Update：2024-04-09 21:40:26
METHYL MERCAPTAN - Nature
Open Data Verified Data
It is a colorless flammable gas at normal temperature and a colorless liquid at low temperature, and has an unpleasant odor. Melting Point -121 to -123 °c. Boiling point 5.9 °c. Flash point <71 °c. The relative density was 0.8665. Slightly soluble in water, 20 deg C for 2.3%. Soluble in alcohol, ether, petroleum ether, etc. It can form explosive mixture with air, and the explosion limit is 3.9% ~ 21.8%.
Last Update：2024-01-02 23:10:35
METHYL MERCAPTAN - Preparation Method
Open Data Verified Data
- the gas phase synthesis of methanol and hydrogen sulfide was carried out with activated alumina as the main catalyst, the reaction temperature was 280~450 ℃, and the reaction pressure was 0. 74~0. 25MPa. This method has high yield and less wastewater.
- The isothiourea salt is formed by the reaction of thiourea and alkyl halide, which is obtained by adding alkali and hydrolyzing.
Last Update：2022-01-01 10:37:35
METHYL MERCAPTAN - Use
Open Data Verified Data
synthetic raw materials, can be used for the synthesis of dyes, medicines (methionine), pesticides (Thio) and so on.
Last Update：2022-01-01 10:37:34
METHYL MERCAPTAN - Safety
Open Data Verified Data
- This product is toxic. The oral lethal concentration of rats is 1%, and the high concentration of steam has the effect of anesthesia, and the wrong ingestion or skin pollution will damage the liver. When operating, wear rubber gloves, protective masks and protective clothing. The maximum allowable concentration in the workplace is 20mg/m3. This product is packed into glass bottles and plastic bottles with screw ports or pressure ports of Iron caps, which should be tightly closed, and then packed into solid wooden boxes. Inside the box, it is lined with straw pads or other soft materials, external use of iron sheet angle or iron wire, iron sheet reinforcement. 20kg net weight per box.
- can also be contained in a steel cylinder, anti-collision when placed, stored in a cool, well-ventilated place, away from fire, not with oxidants, flammable substances, acids, it is not allowed to be exposed to sunlight, or to be wet by rain or water, and a "flammable item" Mark shall be provided on the outside of the container.
Last Update：2022-01-01 10:37:35
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