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Catalytic converter. A catalytic converter is an exhaust emission control device which converts toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction. Catalytic converters are usually used with internal combustion engines fueled by gasoline or diesel, including ...
Catalysis. An air filter that uses a low-temperature oxidation catalyst to convert carbon monoxide to less toxic carbon dioxide at room temperature. It can also remove formaldehyde from the air. Catalysis (/ kəˈtæləsɪs /) is the increase in rate of a chemical reaction due to an added substance known as a catalyst[1][2] (/ ˈkætəlɪst /).
Acid catalysis. In acid-catalyzed Fischer esterification, the proton binds to oxygens and functions as a Lewis acid to activate the ester carbonyl (top row) as an electrophile, and converts the hydroxyl into the good leaving group water (bottom left). Both lower the kinetic barrier and speed up the attainment of chemical equilibrium.
In chemistry, a catalytic cycle is a multistep reaction mechanism that involves a catalyst. [1] The catalytic cycle is the main method for describing the role of catalysts in biochemistry, organometallic chemistry, bioinorganic chemistry, materials science, etc. Since catalysts are regenerated, catalytic cycles are usually written as a sequence ...
Turnover number. In chemistry, the term " turnover number " has two distinct meanings. In enzymology, the turnover number (kcat) is defined as the limiting number of chemical conversions of substrate molecules per second that a single active site will execute for a given enzyme concentration [ET] for enzymes with two or more active sites. [1 ...
Lewis acid catalysis. In Lewis acid catalysis of organic reactions, a metal-based Lewis acid acts as an electron pair acceptor to increase the reactivity of a substrate. Common Lewis acid catalysts are based on main group metals such as aluminum, boron, silicon, and tin, as well as many early (titanium, zirconium) and late (iron, copper, zinc ...
Selective catalytic reduction. CATALYTIC REDUCTION. Selective catalytic reduction (SCR) means of converting nitrogen oxides, also referred to as NO. x with the aid of a catalyst into diatomic nitrogen (N. 2), and water (H. 2O). A reductant, typically anhydrous ammonia (NH. 3), aqueous ammonia (NH. 4OH), or a urea (CO (NH.
Transesterification is the process of exchanging the organic functional group R″ of an ester with the organic group R' of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst. [1] Strong acids catalyze the reaction by donating a proton to the carbonyl group, thus making it a more potent electrophile.