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Thiuram
Thiuram disulfides are a class of organosulfur compounds with the formula (R2NCSS)2. Many examples are known, but popular ones include R = Me and R = Et. They are disulfides obtained by oxidation of the dithiocarbamates. These compounds are used in sulfur vulcanization of rubber as well as in the manufacture of pesticides and drugs. They are typically white or pale yellow solids that are soluble in organic solvents. Preparation, structure, reactions Thiuram disulfides are prepared by oxidizing the salts of the corresponding dithiocarbamates (e.g. sodium diethyldithiocarbamate). Typical oxidants employed include chlorine and hydrogen peroxide: : Thiuram disulfides react with Grignard reagents to give esters of dithiocarbamic acid, as in the preparation of methyl dimethyldithiocarbamate: : The compounds feature planar dithiocarbamate subunits and are linked by an S−S bond of 2.00 Å. The C(S)−N bond is short (1.33 Å), indicative of multiple bonding. The dihed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetramethylthiuram Sulfide
Tetramethylthiuram sulfide is an organosulfur compound with the formula ((CH3)2NCS)2S. It is a yellow solid that is soluble in organic solvents. It is the parent member of a large class of tetraalkylthiuram sulfides. It is used as an activator in the sulfur vulcanization of natural and butyl rubbers. Synthesis and structure It is prepared by desulfuration of tetramethylthiuram disulfides with triphenylphosphine or cyanide: :(Me2NCSS)2 + PPh3 → (Me2NCS)2S + SPPh3 According to X-ray crystallography, the molecule consists of two planar (CH3)2NCS subunits joined by a sulfide Sulfide (also sulphide in British English) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to large families o .... The dihedral angle between the subunits is close to 90°. References Organosulfur compounds {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur Vulcanization
Sulfur vulcanization is a chemical process for converting natural rubber or related polymers into materials of varying hardness, elasticity, and mechanical durability by heating them with sulfur or sulfur-containing compounds. Sulfur forms cross-linking bridges between sections of polymer chains which affects the mechanical properties. Many products are made with vulcanized rubber, including tires, shoe soles, hoses, and conveyor belts. The term is derived from Vulcan (mythology), Vulcan, the Roman god of fire. The main polymers subjected to sulfur vulcanization are polyisoprene (natural rubber, NR), polybutadiene rubber (BR) and styrene-butadiene rubber (SBR), and ethylene propylene diene monomer rubber (EPDM rubber). All of these materials contain allyl, alkene groups adjacent to methylene groups. Other specialty rubbers may also be vulcanized, such as nitrile rubber (NBR) and butyl rubber (IIR). Vulcanization, in common with the curing of other thermosetting polymers, is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disulfiram
Disulfiram is a medication used to support the treatment of chronic alcoholism by producing an acute sensitivity to ethanol (drinking alcohol). Disulfiram works by Enzyme inhibition, inhibiting the enzyme aldehyde dehydrogenase (specifically ALDH2), causing many of the effects of a hangover to be felt immediately following alcohol (drug), alcohol consumption. Disulfiram plus alcohol, even small amounts, produces flushing, throbbing in the head and neck, a throbbing headache, respiratory difficulty, nausea, copious vomiting, sweating, thirst, chest pain, palpitation, dyspnea, shortness of breath, hyperventilation, tachycardia, fast heart rate, hypotension, low blood pressure, Syncope (medicine), fainting, marked uneasiness, weakness, vertigo, blurred vision, and confusion. In severe reactions there may be respiratory depression, cardiovascular collapse, arrhythmia, abnormal heart rhythms, myocardial infarction, heart attack, acute congestive heart failure, unconsciousness, convulsi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Dimethyldithiocarbamate
Methyl dimethyldithiocarbamate is the organosulfur compound with the formula . It is the one of simplest dithiocarbamic esters. It is a white volatile solid that is poorly soluble in water but soluble in many organic solvents. It was once used as a pesticide. Methyl dimethyldithiocarbamate can be prepared by methylation of salts of dimethyldithiocarbamate: : It can also be prepared by the reaction of a tetramethylthiuram disulfide Thiuram disulfides are a class of organosulfur compounds with the formula (R2NCSS)2. Many examples are known, but popular ones include R = Me and R = Et. They are disulfides obtained by oxidation of the dithiocarbamates. These compounds are use ... with methyl Grignard reagents: :{{chem2, CH3)2NC(S)S + CH3MgBr → (CH3)2NC(S)SCH3 + (CH3)2NCS2MgBr References Dithiocarbamates Dimethylamino compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiocarbamoyl Chloride
Dimethylthiocarbamoyl chloride is an organosulfur compound with the formula (CH3)2NC(S)Cl. A yellow solid, it is often encountered as a yellow syrup. It is a key reagent in the synthesis of arylthiols via the Newman-Kwart rearrangement. Synthesis and reactions Representative of other thiocarbamoyl chlorides, dimethylthiocarbamoyl chloride is electrophilic, serving as a source of R2NC(S)+.R. J. Cremlyn "An Introduction to Organosulfur Chemistry" John Wiley and Sons: Chichester (1996). It is analogous to dimethylcarbamoyl chloride (R2NC(O)Cl). Dimethylthiocarbamoyl chloride is prepared by chlorination of the related tetramethylthiuram disulfide: : e2NC(S)sub>2S2 + 3 Cl2 → 2 Me2NC(S)Cl + 2 SCl2 Dimethylthiocarbamoyl chloride reacts with dithiocarbamates (R2NCS{{su, b=2, p=−) to give thiuram sulfides 2NC(S)sub>2S. With methanethiolate, it gives methyl dimethyldithiocarbamate Methyl dimethyldithiocarbamate is the organosulfur compound with the formula . It is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dithiocarbamate
In organic chemistry, a dithiocarbamate is a chemical compound with the general formula . It contains the functional group with the Chemical structure, structure . It is the analog of a carbamate in which both oxygen atoms are replaced by sulfur atoms (when only one oxygen is replaced the result is thiocarbamate). Dithiocarbamate also refers to the dithiocarbamate ion and its salts. A common example is sodium diethyldithiocarbamate . Dithiocarbamates and their derivatives are widely used in the vulcanization of rubber. Formation Many secondary amines react with carbon disulfide and sodium hydroxide to form dithiocarbamate salts: : Ammonia reacts with carbon disulfide, similarly, to give ammonium dithiocarbamate: : Dithiocarbamate salts are pale colored solids that are soluble in water and Solvent, polar organic solvents. Dithiocarbamic acid A primary amine and carbon disulfide react to give a dithiocarbamic acid: : In the presence of diimides or pyridine, these acids convert t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patch Test
A patch test is a diagnostic method used to determine which specific substances cause allergic inflammation of a patient's skin. Patch testing helps identify which substances may be causing a delayed-type allergic reaction in a patient and may identify allergens not identified by blood testing or skin prick testing. It is intended to produce a local allergic reaction on a small area of the patient's back, where the diluted chemicals were planted. The chemicals included in the patch test kit are the offenders in approximately 85–90 percent of contact allergic eczema and include chemicals present in metals (''e.g.'', nickel), rubber, leather, formaldehyde, lanolin, fragrance, toiletries, hair dyes, medicine, pharmaceutical items, food, drink, preservative, and other additives. Mechanism A patch test relies on the principle of a type IV hypersensitivity reaction. The first step in becoming allergic is sensitization. When skin is exposed to an allergen, the antigen-pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiram
Thiram is the simplest thiuram disulfide and the oxidized dimer of dimethyldithiocarbamate. It is used as a fungicide, ectoparasiticide to prevent fungal diseases in seed and crops and similarly as an animal repellent to protect fruit trees and ornamentals from damage by rabbits, rodents and deer. It is effective against Stem gall of coriander, damping off, smut of millet, neck rot of onion, etc. Thiram has been used in the treatment of human scabies, as a sun screen and as a bactericide applied directly to the skin or incorporated into soap. Thiram is also used as a sulfur source and secondary accelerator the sulfur vulcanization Sulfur vulcanization is a chemical process for converting natural rubber or related polymers into materials of varying hardness, elasticity, and mechanical durability by heating them with sulfur or sulfur-containing compounds. Sulfur forms cros ... of rubbers. Usage Thiram was traditionally used in apple and wine farming. Since 2010 most thira ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Diethyldithiocarbamate
Sodium diethyldithiocarbamate is the organosulfur compound with the formula . It is a pale yellow, water soluble salt. Preparation Sodium diethyldithiocarbamate typically crystallizes from water as the trihydrate . The anhydrous salt and the trihydrate are often used interchangeably. Sodium diethyldithiocarbamate is obtained by treating carbon disulfide with diethylamine in the presence of sodium hydroxide: :CS2 + HN(C2H5)2 + NaOH → NaS2CN(C2H5)2 + H2O Other dithiocarbamates can be prepared similarly from secondary amines and carbon disulfide. They are used as chelating agents for transition metal ions and as precursors to herbicides and vulcanization reagents. Reactions Oxidation of sodium diethyldithiocarbamate gives the disulfide, also called a thiuram disulfide (Et = ethyl): : Dithiocarbamates are nucleophiles and thus can be alkylated. Even dichloromethane suffices: : Diethyldithiocarbamate reacts with many metal salts to give transition metal dithiocar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcoholism
Alcoholism is the continued drinking of alcohol despite it causing problems. Some definitions require evidence of dependence and withdrawal. Problematic use of alcohol has been mentioned in the earliest historical records. The World Health Organization (WHO) estimated there were 283 million people with alcohol use disorders worldwide . The term ''alcoholism'' was first coined in 1852, but ''alcoholism'' and ''alcoholic'' are considered stigmatizing and likely to discourage seeking treatment, so diagnostic terms such as ''alcohol use disorder'' and ''alcohol dependence'' are often used instead in a clinical context. Alcohol is addictive, and heavy long-term alcohol use results in many negative health and social consequences. It can damage all the organ systems, but especially affects the brain, heart, liver, pancreas, and immune system. Heavy alcohol usage can result in trouble sleeping, and severe cognitive issues like dementia, brain damage, or Wernicke–Kors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triphenylphosphine
Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is versatile compound that is widely used as a reagent in organic synthesis and as a ligand for transition metal complexes, including ones that serve as catalysts in organometallic chemistry. PPh3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether. Preparation and structure Triphenylphosphine can be prepared in the laboratory by treatment of phosphorus trichloride with phenylmagnesium bromide or phenyllithium. The industrial synthesis involves the reaction between phosphorus trichloride, chlorobenzene, and sodium: :PCl3 + 3 PhCl + 6 Na → PPh3 + 6 NaCl Triphenylphosphine crystallizes in triclinic and monoclinic modification. In both cases, the molecule adopts a pyramidal structure with propeller-like arrangement of the thre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetaldehyde
Acetaldehyde (IUPAC systematic name ethanal) is an organic compound, organic chemical compound with the chemical formula, formula , sometimes abbreviated as . It is a colorless liquid or gas, boiling near room temperature. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale in industry. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants. It is also produced by the partial oxidation of ethanol by the liver enzyme alcohol dehydrogenase and is a contributing cause of hangover after alcohol (drug), alcohol consumption. Pathways of exposure include air, water, land, or groundwater, as well as drink and smoke. Consumption of disulfiram inhibits acetaldehyde dehydrogenase, the enzyme responsible for the metabolism of acetaldehyde, thereby causing it to build up in the body. International Agency for Research on Cancer, The International Agency for Research on Cancer (IARC) has listed acetaldehyde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
