Pages in category "Corrosion inhibitors"
The following 25 pages are in this category, out of 25 total. This list may not reflect recent changes (learn more).
The following 25 pages are in this category, out of 25 total. This list may not reflect recent changes (learn more).
1. Corrosion inhibitor – A corrosion inhibitor 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. The effectiveness of a corrosion inhibitor depends on composition, quantity of water. A common mechanism for inhibiting corrosion involves formation of a coating, often a passivation layer, permanent treatments such as chrome plating are not generally considered inhibitors, however. Instead corrosion inhibitors are additives to the fluids that surround the metal or related object, the nature of the corrosive inhibitor depends on the material being protected, which are most commonly metal objects, and on the corrosive agent to be neutralized. The corrosive agents are oxygen, hydrogen sulfide, and carbon dioxide. Related inhibitors of oxygen corrosion are hexamine, phenylenediamine, and dimethylethanolamine, antioxidants such as sulfite and ascorbic acid are sometimes used. Some corrosion inhibitors form a coating on the surface by chemisorption. Benzotriazole is one such species used to protect copper, for lubrication, zinc dithiophosphates are common - they deposit sulfide on surfaces. The suitability of any given chemical for a task in hand depends on many factors, volatile amines are used in boilers to minimize the effects of acid. In some cases, the form a protective film on the steel surface and, at the same time. An inhibitor that acts both in a cathodic and anodic manner is termed a mixed inhibitor, benzotriazole inhibits the corrosion and staining of copper surfaces. Corrosion inhibitors are added to paints. A pigment with anticorrosive properties is zinc phosphate, compounds derived from tannic acid or zinc salts of organonitrogens can be used together with anticorrosive pigments. Other corrosion inhibitors are Anticor 70, Albaex, Ferrophos, antiseptics are used to counter microbial corrosion. Benzalkonium chloride is used in oil field industry. In oil refineries, hydrogen sulfide can corrode steels so it is removed often using air, corrosion inhibitors are commonly added to coolants, fuels, hydraulic fluids, boiler water, engine oil, and many other fluids used in industry. For fuels, various corrosion inhibitors can be used, dCI-4A, widely used in commercial and military jet fuels, acts also as a lubricity additive. Can be also used for gasolines and other distillate fuels, dCI-6A, for motor gasoline and distillate fuels, and for U. S
2. Barium borate – Barium borate is an inorganic compound, a borate of barium with a chemical formula BaB2O4 or Ba2. It is available as a hydrate or dehydrated form, as powder or colorless crystals. The crystals exist in the high-temperature α phase and low-temperature β phase, abbreviated as BBO, barium borate exists in two major crystalline forms, alpha and beta. The low-temperature beta phase converts into the alpha phase upon heating to 925 °C, β-Barium borate differs from the α form by the positions of the barium ions within the crystal. Both phases are birefringent, however the α phase possesses centric symmetry, alpha barium borate, α-BaB2O4 is an optical material with a very wide optical transmission window from about 190 nm to 3500 nm. It has good properties and is a suitable material for high-power ultraviolet polarization optics. It can replace calcite, titanium dioxide or lithium niobate in Glan–Taylor prisms, Glan–Thompson prisms, walk-off beam splitters and it has low hygroscopicity, and its Mohs hardness is 4.5. Its damage threshold is 1 GW/cm2 at 1064 nm and 500 MW/cm2 at 355 nm, beta barium borate, β-BaB2O4, is a nonlinear optical material transparent in the range ~190–3300 nm. It can be used for spontaneous parametric down-conversion and its Mohs hardness is also 4.5. Barium borate has strong negative uniaxial birefringence and can be phase-matched for type I second-harmonic generation from 409.6 to 3500 nm, the temperature sensitivity of the indices of refraction is low, leading to an unusually large temperature phase-matching bandwidth. Barium borate can be prepared by reaction of a solution of boric acid with barium hydroxide. The prepared γ-barium borate contains water of crystallization that can not be removed by drying at 120 °C. Dehydrated γ-barium borate can be prepared by heating to 300–400 °C, calcination at about 600–800 °C causes complete conversion to the β form. BBO prepared by this method does not contain trace amounts of BaB2O2 BBO crystals for nonlinear optics can be grown from fluxed melt of barium borate, sodium oxide, thin films of barium borate can be prepared by MOCVD from barium hydro-triborate. Different phases can be obtained depending on deposition temperatures, thin films of beta-barium borate can be prepared by sol-gel synthesis. Barium borate monohydrate is prepared from the solution of barium sulfide and it is used as an additive to e. g. paints as flame retardant, mold inhibitor, and corrosion inhibitor. It is also used as a white pigment, barium borate dihydrate is prepared from the solution of sodium metaborate and barium chloride at 90–95 °C. After cooling to room temperature, white powder is precipitated, barium borate dihydrate loses water at above 140 °C
3. Benzotriazole – Benzotriazole is a heterocyclic compound containing three nitrogen atoms, with the chemical formula C6H5N3. This aromatic compound is colorless and polar and can be used in various fields and its five-membered ring can exist in tautomers A and B, and the derivatives of both tautomers, structures C and D also can be produced. Various structural analyses with UV, IR and 1H-NMR spectra indicated that isomer A is predominantly present at room temperature, the bond between positions 1 and 2 and the one between positions 2 and 3 have proved to have the same bond properties. Moreover, the proton does not tightly bind to any of the nitrogen atoms, therefore, the BTA can lose a proton to act as a weak acid or accept a proton using the lone pair electrons located on its nitrogen atoms as a very weak Bronsted base. Not only can it act either as an acid or base, it can bind to other species. Applying this property, the BTA can form a coordination compound on a copper surface. A synthesis of the BTA involves the reaction of o-phenylenediamine, sodium nitrite, the conversion proceeds via diazotization of one of the amine groups. The synthesis can be improved when the reaction is carried out at low temperatures, typical batch purity is 98. 5% or greater Benzotriazole has been known for its great versatility. It has already used as a restrainer in photographic emulsions. More importantly, it has extensively used as a corrosion inhibitor in the atmosphere. Also, its derivatives and their effectiveness as drug precursors have been drawing attention, besides all the application mentioned above, the BTA can be used as antifreezes, heating and cooling systems, hydraulic fluids and vapor phase inhibitors as well. Benzotriazole is a corrosion inhibitor for copper and its alloys by preventing undesirable surface reactions. It is known that a layer, consisting of a complex between copper and benzotriazole, is formed when copper is immersed in a solution containing benzotriazole. The passive layer is insoluble in aqueous and many organic solutions, there is a positive correlation between the thickness of the passive layer and the efficiency of preventing corrosion. BTA is used in conservation, notably for the treatment of bronze disease, the exact structure of the copper-BTA complex is controversial and many proposals have been suggested. Benzotriazole derivatives have chemical and biological properties that are versatile in the pharmaceutical industry, Benzotriazole derivatives act as agonists for many proteins. The methodology is not only limited to heterocyclization but was successful for polynuclear hydrocarbons of small carbocyclic systems. Trazolopride & Tribendilol are other examples of drugs
4. Bis(triethoxysilylpropyl)tetrasulfide – Bistetrasulfide is an organosulfur compound with the formula S42. The molecule consists of two trialkoxysilyl propyl groups linked with a polysulfide and it is often sold as a mixture with the trisulfide. The compound is a viscous liquid that is soluble in ordinary organic solvents such as toluene. The compound is added to rubber compositions that contain silica filler, the tetrasulfide group is a polysulfide, which means that it consists of a chain of sulfur atoms. S-S bonds are susceptible to reduction, attachment to metals, the triethoxysilyl groups are susceptible to hydrolysis, resulting in cross-linking via sol-gel condensation. In the usual application of chemical, the hydrolyzed siloxy groups attach to silica particles
5. Cinnamaldehyde – Cinnamaldehyde is an organic compound with the formula C6H5CH=CHCHO. Occurring naturally as predominately the trans isomer, it gives cinnamon its flavor and odor and it is a flavonoid that is naturally synthesized by the shikimate pathway. This pale yellow, viscous liquid occurs in the bark of cinnamon trees, the essential oil of cinnamon bark is about 50% cinnamaldehyde. Cinnamaldehyde was isolated from cinnamon essential oil in 1834 by Dumas and Péligot, the molecule consists of a benzene ring attached to an unsaturated aldehyde. As such, the molecule can be viewed as a derivative of acrolein and its color is due to the π → π* transition, increased conjugation in comparison with acrolein shifts this band towards the visible. The biosynthesis of cinnamaldehyde begins with deamination of L-phenylalalanine into cinnamic acid by the action of phenylalanine ammonia lyase, PAL catalyzes this reaction by a non-oxidative deamination. This deamination relies on the MIO prosthetic group of PAL, PAL gives rise to trans-cinnamic acid. In the second step, 4-coumarate, CoA ligase converts cinnamic acid to cinnamoyl-CoA by an acid-thiol ligation, 4CL uses ATP to catalyze the formation of cinnamoyl-CoA. 4CL effects this reaction in two steps, 4CL forms a hydroxycinnamate-AMP anhydride, followed by a nucleophile attack on the carbonyl of the acyl adenylate. Cinnamoyl-CoA is reduced by NADPH catalyzed by CCR to form cinnamaldehyde, several methods of laboratory synthesis exist, but cinnamaldehyde is most economically obtained from the steam distillation of the oil of cinnamon bark. The compound can be prepared from related compounds such as cinnamyl alcohol, cinnamaldehyde occurs widely, and closely related compounds give rise to lignin. All such compounds are biosynthesized starting from phenylalanine, which undergoes conversion, cinnamoyl-CoA reductase is an enzyme responsible for the production of cinnamoyl-CoA from cinnamaldehyde. The most obvious application for cinnamaldehyde is as flavoring in chewing gum, ice cream, candy and it is also used in some perfumes of natural, sweet, or fruity scents. Almond, apricot, butterscotch, and other aromas may partially employ the compound for their pleasant smells, cinnamaldehyde can be used as a food adulterant, powdered beechnut husk aromatized with cinnamaldehyde can be marketed as powdered cinnamon. Some breakfast cereals contain as much as 187 ppm cinnamaldehyde, cinnamaldehyde is also used as a fungicide. Proven effective on over 40 different crops, cinnamaldehyde is typically applied to the systems of plants. Its low toxicity and well-known properties make it ideal for agriculture, cinnamaldehyde is an effective insecticide, and its scent is also known to repel animals, such as cats and dogs. It has been tested as a safe and effective insecticide against mosquito larvae, a concentration of 29 ppm of cinnamaldehyde kills half of Aedes aegypti mosquito larvae in 24 hours