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Mercaptobenzothiazole
2-Mercaptobenzothiazole is an organosulfur compound with the formula . It is used in the sulfur vulcanization of rubber. Structure The molecule is planar with a C=S double bond, so the name ''mercapto''benzothiazole is a misnomer. It is not a thiol, but instead is a thioamide, in the solid state, gas-phase, and in solution. A more appropriate name is benzothiazoline-2-thione. Solution measurements by NMR spectroscopy reveal no evidence for the thiol tautomer. Theory also indicates that the thiol tautomer is about 39 kJ/mol higher in energy than the thioamide. Synthesis and reactions The compound has been produced by many methods. The industrial route entails the high temperature reaction of aniline and carbon disulfide in the presence of sulfur, which proceeds by this idealized equation: : The traditional route is the reaction of 2-aminothiophenol and carbon disulfide: : This method was developed by the discoverer of the compound, A. W. Hoffmann. Other routes developed by Hof ... [...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 and electronic properties. Many products are made with vulcanized rubber, including tires, shoe soles, hoses, and conveyor belts. The term is derived from 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 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 gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzothiazole
Benzothiazole is an aromatic heterocyclic compound with the chemical formula . It is colorless, slightly viscous liquid. Although the parent compound, benzothiazole is not widely used, many of its derivatives are found in commercial products or in nature. Firefly luciferin can be considered a derivative of benzothiazole. Structure and preparation Benzothiazoles consist of a 5-membered 1,3-thiazole ring fused to a benzene ring. The nine atoms of the bicycle and the attached substituents are coplanar. Benzothiazoles are prepared by treatment of 2-mercaptoaniline with acid chlorides: :C6H4(NH2)SH + RC(O)Cl → C6H4(NH)SCR + HCl + H2O Uses Benzothiazole occurs naturally in some foods but is also used as a food additive. It has a sulfurous odor and meaty flavor. The European Food Safety Authority assessment had "no safety concern at estimated levels of intake as a flavouring substance". The heterocyclic core of the molecule is readily substituted at the unique methy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-Aminothiophenol
2-Aminothiophenol is an organosulfur compound with the formula C6H4(SH)(NH2). It is a colorless oily solid, although impure samples can be deeply colored. It is soluble in organic solvents and in basic water. It is a precursor to benzothiazoles, some of which are bioactive or are dyes. Isomers of aminothiophenols include 3-aminothiophenol and 4-aminothiophenol. 2-Aminothiophenol can prepared in two steps, starting with the reaction of aniline with carbon disulfide followed by hydrolysis of the resulting mercaptobenzothiazole 2-Mercaptobenzothiazole is an organosulfur compound with the formula . It is used in the sulfur vulcanization of rubber. Structure The molecule is planar with a C=S double bond, so the name ''mercapto''benzothiazole is a misnomer. It is not a t ....Chedekel, Miles R.; Sharp, Dale E.; Jeffery, Gary A. "Synthesis of o-aminothiophenols" Synthetic Communications 1980, volume 10, pp. 167-73. It can also obtained by zinc reduction of 2-nitrobenzene sulfonyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antifreeze
An antifreeze is an additive which lowers the freezing point of a water-based liquid. An antifreeze mixture is used to achieve freezing-point depression for cold environments. Common antifreezes also increase the boiling point of the liquid, allowing higher coolant temperature. However, all common antifreeze additives also have lower heat capacities than water, and do reduce water's ability to act as a coolant when added to it. Because water has good properties as a coolant, water plus antifreeze is used in internal combustion engines and other heat transfer applications, such as HVAC chillers and solar water heaters. The purpose of antifreeze is to prevent a rigid enclosure from bursting due to expansion when water freezes. Commercially, both the ''additive'' (pure concentrate) and the ''mixture'' (diluted solution) are called antifreeze, depending on the context. Careful selection of an antifreeze can enable a wide temperature range in which the mixture remains in the liq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cutting Fluid
Cutting fluid is a type of coolant and lubricant designed specifically for metalworking processes, such as machining and stamping. There are various kinds of cutting fluids, which include oils, oil-water emulsions, pastes, gels, aerosols (mists), and air or other gases. Cutting fluids are made from petroleum distillates, animal fats, plant oils, water and air, or other raw ingredients. Depending on context and on which type of cutting fluid is being considered, it may be referred to as cutting fluid, cutting oil, cutting compound, coolant, or lubricant. Most metalworking and machining processes can benefit from the use of cutting fluid, depending on workpiece material. Common exceptions to this are cast iron and brass, which may be machined dry (though this is not true of all brasses, and any machining of brass will likely benefit from the presence of a cutting fluid). The properties that are sought after in a good cutting fluid are the ability to: * Keep the workpiece at a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corrosion Inhibitor
In chemistry, a corrosion inhibitor or anti-corrosive is a chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a material, typically a metal or an alloy, that comes into contact with the fluid. The effectiveness of a corrosion inhibitor depends on fluid composition, quantity of water, and flow regime. Corrosion inhibitors are common in industry, and also found in over-the-counter products, typically in spray form in combination with a lubricant and sometimes a penetrating oil. They may be added to water to prevent leaching of lead or copper from pipes. A common mechanism for inhibiting corrosion involves formation of a coating, often a passivation layer, which prevents access of the corrosive substance to the metal. Permanent treatments such as chrome plating are not generally considered inhibitors, however: corrosion inhibitors are additives to the fluids that surround the metal or related object. Types The nature of the corrosive inhibitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in a directly usable metallic form (native metals). This led to very early human use in several regions, from circa 8000 BC. Thousands of years later, it was the first metal to be smelted from sulfide ores, circa 5000 BC; the first metal to be cast into a shape in a mold, c. 4000 BC; and the first metal to be purposely alloyed with another metal, tin, to create br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organosulfur Compound
Organosulfur compounds are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature abounds with organosulfur compounds—sulfur is vital for life. Of the 20 common amino acids, two (cysteine and methionine) are organosulfur compounds, and the antibiotics penicillin and sulfa drugs both contain sulfur. While sulfur-containing antibiotics save many lives, sulfur mustard is a deadly chemical warfare agent. Fossil fuels, coal, petroleum, and natural gas, which are derived from ancient organisms, necessarily contain organosulfur compounds, the removal of which is a major focus of oil refineries. Sulfur shares the chalcogen group with oxygen, selenium, and tellurium, and it is expected that organosulfur compounds have similarities with carbon–oxygen, carbon–selenium, and carbon–tellurium compounds. A classical chemical test for the detection of sulfur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper Alloys
Copper alloys are metal alloys that have copper as their principal component. They have high resistance against corrosion. The best known traditional types are bronze, where tin is a significant addition, and brass, using zinc instead. Both of these are imprecise terms, having both been commonly referred to as lattens in the past. Today the term ''copper alloy'' tends to be substituted, especially by museums. Composition The similarity in external appearance of the various alloys, along with the different combinations of elements used when making each alloy, can lead to confusion when categorizing the different compositions. There are as many as 400 different copper and copper alloy compositions loosely grouped into the categories: copper, high copper alloy, brasses, bronzes, copper nickels, copper–nickel–zinc (nickel silver), leaded copper, and special alloys. The following table lists the principal alloying element for four of the more common types used in mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat-transfer Oil
An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated lipids that are liquid at room temperature. The general definition of oil includes classes of chemical compounds that may be otherwise unrelated in structure, properties, and uses. Oils may be animal, vegetable, or petrochemical in origin, and may be volatile or non-volatile. They are used for food (e.g., olive oil), fuel (e.g., heating oil), medical purposes (e.g., mineral oil), lubrication (e.g. motor oil), and the manufacture of many types of paints, plastics, and other materials. Specially prepared oils are used in some religious ceremonies and rituals as purifying agents. Etymology First attested in English 1176, the word ''oil'' comes from Old French ''oile'', from Latin ''oleum'', which in turn comes from the Greek (''elaion'') ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electroplating
Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the redox, reduction of cations of that metal by means of a direct current, direct electric current. The part to be coated acts as the cathode (negative electrode) of an electrolytic cell; the electrolyte is a solution (chemistry), solution of a salt (chemistry), salt of the metal to be coated; and the anode (positive electrode) is usually either a block of that metal, or of some inert electrical conductor, conductive material. The current is provided by an external power supply. Electroplating is widely used in industry and decorative arts to improve the surface qualities of objects—such as resistance to abrasion (mechanical), abrasion and corrosion, lubrication, lubricity, reflectivity, electrical conductivity, or appearance. It is used to build up thickness on undersized or worn-out parts, or to manufacture metal plates with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
