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Encyclopedia > Catalysis

In chemistry and biology, catalysis is the acceleration (increase in rate) of a chemical reaction by means of a substance called a catalyst, which is itself not consumed by the overall reaction. More generally, one may at times call anything that accelerates a process, a "catalyst" (for example, a "catalyst for political change"). The word is derived from the Greek noun κατάλυσις, related to the verb καταλύειν, meaning to annul or to untie or to pick up. Look up catalyst in Wiktionary, the free dictionary. ... For other uses, see Chemistry (disambiguation). ... For the song by Girls Aloud see Biology (song) Biology studies the variety of life (clockwise from top-left) E. coli, tree fern, gazelle, Goliath beetle Biology (from Greek: βίος, bio, life; and λόγος, logos, speech lit. ... Iron rusting - a chemical reaction with a slow reaction rate. ... For other uses, see Chemical reaction (disambiguation). ... In linguistics, a noun or noun substantive is a lexical category which is defined in terms of how its members combine with other grammatical kinds of expressions. ... It has been suggested that Verbal agreement be merged into this article or section. ...


A catalyst provides an alternative route to products, the catalytic route being subject to lower activation energy than in the uncatalyzed reaction. A lowered activation energy increases the reaction rate. Catalysts change in the course of a reaction but are regenerated. The sparks generated by striking steel against a flint provide the activation energy to initiate combustion in this Bunsen burner. ... Iron rusting - a chemical reaction with a slow reaction rate. ...


A good example of a catalyst is in the disproportionation of hydrogen peroxide to give water and oxygen: Disproportionation is a concept in chemistry and is a redox reaction where a reactant is both oxidised and reduced in the same chemical reaction. ... R-phrases , , , , S-phrases , , , ,, , , , Flash point Non-flammable Related Compounds Related compounds Water Ozone Hydrazine Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ...

2 H2O2 → 2 H2O + O2

This reaction is slow (hence one can buy solutions of hydrogen peroxide). Upon the addition of manganese dioxide to hydrogen peroxide, the reaction occurs rapidly as signaled by effervescence of oxygen. In demonstrations, the evolved oxygen is detectable by its effect on a glowing splint. The manganese dioxide may be recovered, and re-used indefinitely, thus it is a catalyst — it is not consumed by the reaction. (The H2O2 sold as a sterilizing agent in drugstores is too dilute for this to work dramatically.) Manganese(IV) oxide (MnO2) is a chemical compound also known as manganese dioxide or manganese oxide. ... Effervesence from soda. ...


A promoter chemically modifies a catalyst but is not itself a catalyst. An inhibitor reduces the effectiveness of (or slows down the effect of) a catalyst. A reaction inhibitor is a substance that prevents or decreases the rate of a chemical reaction. ...

Contents

History

The phrase catalysis was coined by Jöns Jakob Berzelius who in 1835 was the first to note that certain chemicals speed up a reaction. Other early chemists involved in catalysis were Alexander Mitscherlich who in 1831[citation needed] referred to contact processes and Johann Wolfgang Döbereiner who spoke of contact action and whose lighter based on hydrogen and a platinum sponge became a huge commercial success in the 1820’s. In the 1880s, Wilhelm Ostwald at Leipzig University started a series of systematic investigations into reactions that were catylized by the presence of acids and bases, and found both that chemical reactions occur at finite rates, and that these rates can be used to determine the strengths of acids and bases. For this work, Ostwald was awarded the 1909 Nobel Prize in Chemistry. Friherre Jöns Jakob Berzelius (August 20, 1779 – August 7, 1848) was a Swedish chemist. ... Alexander Mitscherlich (b. ... Johann Wolfgang Döbereiner Johann Wolfgang Döbereiner (December 13, 1780 – March 24, 1849) was a German chemist. ... A metal naphtha lighter A lighter is a device used to create fire with the intent to ignite another substance such as a cigarette, smoking pipe, or charcoal in a grill. ... This article is about the chemistry of hydrogen. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... Friedrich Wilhelm Ostwald (commonly just Wilhelm Ostwald) (September 2, 1853 - April 4, 1932) was a German chemist. ... The University of Leipzig is one of the oldest universities in Europe. ... For alternative meanings see acid (disambiguation). ... This is a list of Nobel Prize laureates in Chemistry from 1901 to 2006. ...


Definitions

Catalysts generally react with one or more reactants to form an intermediate that subsequently give the final reaction product, in the process regenerating the catalyst. The following is a typical reaction scheme, where C represents the catalyst, A and B are reactants, and D is the product of the reaction of A and B:

A + C → AC (1)
B + AC → ABC (2)
ABC → CD (3)
CD → C + D (4)

Although the catalyst (C) is consumed by reaction 1, it is subsequently produced by reaction 4, so for the overall reaction:

A + B → D

Catalytic cycles

Main article: catalytic cycle

A catalytic cycle is another term for mechanism. Catalytic cycles are central to any discussion of catalysis, be it in biochemistry, organometallic chemistry, or solid state chemistry. A catalytic cycle in chemistry is a concept that appreciates the notion that in a chemical reaction a catalyst is often first consumed and then regenerated in the course of a catalytic reaction sequence thereby elaborating on the classical view that of a catalyst not taking part in the reaction... Biochemistry (from Greek: , bios, life and Egyptian kēme, earth[1]) is the study of the chemical processes in living organisms. ... n-butyllithium, an organometallic compound. ...


Often, a so-called sacrificial catalyst is also part of the reaction system with the purpose of regenerating the true catalyst in each cycle. As the name implies the sacrificial catalyst is not regenerated and is instead irreversibly consumed. This sacrificial compound is also known as a stoichiometric catalyst when added in stoichiometric quantities compared to the main reactant. Usually the true catalyst is an expensive and complex molecule and added in quantities as small as possible. The stoichiometric catalyst on the other hand should be cheap and abundant. In chemistry, stoichiometry is the study of the combination of elements in chemical reactions. ...


Catalysts and reaction energetics

Generic potential energy diagram showing the effect of a catalyst in an hypothetical exothermic chemical reaction. The presence of the catalyst opens a different reaction pathway (shown in red) with a lower activation energy. The final result and the overall thermodynamics are the same.

Catalysts work by providing an (alternative) mechanism involving a different transition state and lower activation energy. The effect of this is that more molecular collisions have the energy needed to reach the transition state. Hence, catalysts can perform reactions that, albeit thermodynamically feasible, would not run without the presence of a catalyst, or perform them much faster, more specific, or at lower temperatures. This can be observed on a Boltzmann distribution and energy profile diagram. This means that catalysts reduce the amount of energy needed to start a chemical reaction. Image File history File links Catalyst_effect. ... Image File history File links Catalyst_effect. ... The sparks generated by striking steel against a flint provide the activation energy to initiate combustion in this Bunsen burner. ... In physics, the Boltzmann distribution predicts the distribution function for the fractional number of particles Ni / N occupying a set of states i which each has energy Ei: where is the Boltzmann constant, T is temperature (assumed to be a sharply well-defined quantity), is the degeneracy, or number of...


Catalysts cannot make energetically unfavorable reactions possible — they have no effect on the chemical equilibrium of a reaction because the rate of both the forward and the reverse reaction are equally affected (see also thermodynamics). The net free energy change of a reaction is the same whether a catalyst is used or not; the catalyst just makes it easier to activate. A burette, an apparatus for carrying out acid-base titration, is an important part of equilibrium chemistry. ... Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dynamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ...


The SI derived unit for measuring the catalytic activity of a catalyst is the katal, which is moles per second. The degree of activity of a catalyst can also be described by the turn over number (or TON) and the catalytic efficiency by the turn over frequency (TOF). The biochemical equivalent is the enzyme unit. SI derived units are part of the SI system of measurement units and are derived from the seven SI base units. ... Katal is the SI derived unit for catalytic activity. ... Turnover Frequency (TOF) Rate of conversion is given as the number of moles converted or produced per unit weight and unit time. ... An enzyme unit is the amount of enzyme that catalyzes the transformation of 1 micromole of substance per minute at 30°C. It is commonly used to measure the specific activity of an enzyme. ...


For more information on the efficiency of enzymatic catalysis see the Enzyme#Kinetics section. Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ...


Autocatalysis

In autocatalysis, a reaction produces catalysts. A single chemical reaction is said to have undergone autocatalysis, or be autocatalytic, if the reaction product is itself the catalyst for that reaction. ...


Types of catalysts

Catalysts can be either heterogeneous or homogeneous. Biocatalysts are often seen as a separate group. Look up Heterogeneous in Wiktionary, the free dictionary. ... ...


Heterogeneous catalysts are present in different phases from the reactants (for example, a solid catalyst in a liquid reaction mixture), whereas homogeneous catalysts are in the same phase (for example, a dissolved catalyst in a liquid reaction mixture). In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... In chemistry, the reactants are the substances that exist at the start of a chemical reaction. ... This box:      For other uses, see Solid (disambiguation). ... For other uses, see Liquid (disambiguation). ... Vapours of hydrogen chloride in a beaker and ammonia in a test tube meet to form a cloud of a new substance, ammonium chloride A chemical reaction is a process that results in the interconversion of chemical substances. ... Solvation is the attraction and association of molecules of a solvent with molecules or ions of a solute. ...


Heterogeneous catalysts

A simple model for heterogeneous catalysis involves the catalyst providing a surface on which the reactants (or substrates) temporarily become adsorbed. Bonds in the substrate become weakened sufficiently for new bonds to be created. The bonds between the products and the catalyst are weaker, so the products are released. Different possible mechanisms for reactions on surfaces are known, depending on how the adsorption takes place (Langmuir-Hinshelwood and Eley-Rideal). Heterogeneous catalysis is a chemistry term which describes catalysis where the catalyst is in a different phase (ie. ... Look up Heterogeneous in Wiktionary, the free dictionary. ... An open surface with X-, Y-, and Z-contours shown. ... For other uses, see Substrate. ... Adsorption is a process that occurs when a gas or liquid solute accumulates on the surface of a solid or, more rarely, a liquid (adsorbent), forming a molecular or atomic film (the adsorbate). ... A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds. ... By reactions on surfaces it is understood reactions in which at least one of the steps of the reaction mechanism is the adsorption of one or more reactants. ... By reactions on surfaces it is understood reactions in which at least one of the steps of the reaction mechanism is the adsorption of one or more reactants. ... By reactions on surfaces it is understood reactions in which at least one of the steps of the reaction mechanism is the adsorption of one or more reactants. ...


For example, in the Haber process to manufacture ammonia, finely divided iron acts as a heterogeneous catalyst. Active sites on the metal allow partial weak bonding to the reactant gases, which are adsorbed onto the metal surface. As a result, the bond within the molecule of a reactant is weakened and the reactant molecules are held in close proximity to each other. In this way the particularly strong triple bond in nitrogen is weakened and the hydrogen and nitrogen molecules are brought closer together than would be the case in the gas phase, so the rate of reaction increases. The Haber Process (also known as Haber–Bosch process) is the reaction of nitrogen and hydrogen to produce ammonia. ... For other uses, see Ammonia (disambiguation). ... For other uses, see Iron (disambiguation). ... Gas phase particles (atoms, molecules, or ions) move around freely Gas is one of the four major states of matter, consisting of freely moving atoms or molecules without a definite shape and without a definite volume. ... In chemistry, a molecule is adsorbed onto a surface when temporary bonds are formed between the surface and the molecule. ... Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons between atoms, in order to produce a mutual attraction, which holds the resultant molecule together. ...


Other heterogeneous catalysts include vanadium(V) oxide in the contact process, nickel in the manufacture of margarine, alumina and silica in the cracking of alkanes and platinum rhodium palladium in catalytic converters. Mesoporous silicates have found utility in heterogeneous reaction catalysis because their large accessible surface area allows for high catalyst loading. Vanadium(V) oxide (V2O5), commonly known as vanadium pentoxide, is the most important compound of vanadium. ... This article or section does not cite its references or sources. ... For other uses, see Nickel (disambiguation). ... Margarine in a tub Margarine (pronunciation: ), as a generic term, can indicate any of a wide range of butter substitutes. ... Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... Cracking-divides a group’s voters into other districts, where they will be ineffective minorities; and kidnapping places two incumbents from the same party in the same district. ... An alkane in organic chemistry is a type of hydrocarbon in which the molecule has the maximum possible number of hydrogen atoms and so has no double bonds (they are saturated). ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... General Name, Symbol, Number rhodium, Rh, 45 Chemical series transition metals Group, Period, Block 9, 5, d Appearance silvery white metallic Standard atomic weight 102. ... For other uses, see Palladium (disambiguation). ... In an automobiles exhaust system, a catalytic converter provides an environment for a chemical reaction where unburned hydrocarbons completely combust. ... There are very few or no other articles that link to this one. ...


In car engines, incomplete combustion of the fuel produces carbon monoxide, which is toxic. The electric spark and high temperatures also allow oxygen and nitrogen to react and form nitrogen monoxide and nitrogen dioxide, which are responsible for photochemical smog and acid rain. Catalytic converters reduce such emissions by adsorbing CO and NO onto catalytic surface, where the gases undergo a redox reaction. Carbon dioxide and nitrogen are desorbed from the surface and emitted as relatively harmless gases: This article is about the chemical reaction combustion. ... For other uses, see Fuel (disambiguation). ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... The chemical compound nitric oxide is a gas with chemical formula NO. It is an important signaling molecule in the body of mammals including humans, one of the few gaseous signaling molecules known. ... [1] R-phrases , S-phrases , , , , , Supplementary data page Structure and properties n, εr, etc. ... It has been suggested that Haze be merged into this article or section. ... The term acid rain is commonly used to mean the deposition of acidic components in rain, snow, fog, dew, or dry particles. ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... R-phrases , , , , S-phrases , , , Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Nitric oxide or Nitrogen monoxide is a chemical compound with chemical formula NO. This gas is an important signaling molecule in the body of... The most fundamental reactions in chemistry are the redox processes. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...

2CO + 2NO → 2CO2 + N2

Many catalysts used in refineries and in petrochemical applications are regenerated and reused multiple times to save costs and energy and to reduce environmental impact from recycling or disposal of spent catalysts.


Homogeneous catalysts

Main article: Homogeneous catalysis

Homogeneous catalysts are in the same phase as the reactants. Homogeneous catalysis is a chemistry term which describes catalysis where the catalyst is in the same phase (ie. ...


In homogeneous catalysis the catalyst is a molecule which facilitates the reaction. The reactant(s) coordinate to the catalyst (or vice versa), are transformed to product(s), which are then released from the catalyst. 3D (left and center) and 2D (right) representations of the terpenoid molecule atisane. ... See Cartesian coordinate system or Coordinates (elementary mathematics) for a more elementary introduction to this topic. ...


Examples of homogeneous catalysts are H+(aq) which acts as a catalyst in esterification, and chlorine free radicals in the break down of ozone. Chlorine free radicals are formed by the action of ultraviolet radiation on chlorofluorocarbons (CFCs). They react with ozone forming oxygen molecules and regenerating chlorine free radicals which then in turn destroys the thin layer that is the ozone. This article is about the chemistry of hydrogen. ... Esterification is the general name for a chemical reaction in which two chemicals (typically an alcohol and an acid) form an ester as the reaction product. ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... In chemistry free radicals are uncharged atomic or molecular species with unpaired electrons or an otherwise open shell configuration. ... For other uses, see Ozone (disambiguation). ... For other uses, see Ultraviolet (disambiguation). ... For other uses, see Radiation (disambiguation). ... For other uses, see CFC (disambiguation). ...

Cl· + O3 → ClO· + O2
ClO· + O· → Cl· + O2

Biocatalysts

Main article: Biocatalysis

In nature enzymes are catalysts in the metabolic pathway. In biochemistry catalysis is also observed with abzymes, ribozymes and deoxyribozymes. Biocatalysts can be thought of as a mixture of a homogenous and heterogeneous catalyst. This is because the enzyme is in solution itself, but the reaction takes place on the enzyme surface. Biocatalysis can be defined as the utilization of natural catalysts, called enzymes, to perform chemical transformations on organic compounds. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... In biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell. ... Biochemistry (from Greek: , bios, life and Egyptian kēme, earth[1]) is the study of the chemical processes in living organisms. ... An abzyme (from antibody and enzyme), also called catmab (from catalytic monoclonal antibody), is a monoclonal antibody with catalytic activity. ... // A ribozyme (from ribonucleic acid enzyme, also called RNA enzyme or catalytic RNA) is an RNA molecule that catalyzes a chemical reaction. ... Deoxyribozymes or DNA enzymes or catalytic DNA, or DNAzymes are DNA molecules with catalytic action. ...


Electrocatalysts

In the context of electrochemistry, specifically in fuel cell engineering, various metal-rich catalysts are used to promote the efficiency of a half reaction that occurs within the fuel cell. One common type of fuel cell electrocatalyst is based upon tiny nanoparticles of platinum which adorn slightly larger carbon particles. When this type of platinum electrocatalyst is in contact with one of the electrodes in a fuel cell, it increases the rate of the redox half reaction in which oxygen gas is reduced to water (or hydroxide or hydrogen peroxide). English chemists John Daniell (left) and Michael Faraday (right), both credited to be founders of electrochemistry as known today. ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... A half reaction is either the oxidation or reduction reaction component of a redox reaction. ... Very Basic Description A nanoparticle is a microscopic particle whose size is measured in nanometers. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... For other uses, see Carbon (disambiguation). ... Alternative meanings: There is also an Electric-type Pokémon named Electrode. ... ed|other uses|reduction}} Illustration of a redox reaction Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... A half reaction is either the oxidation or reduction reaction component of a redox reaction. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Hydroxide is a polyatomic ion consisting of oxygen and hydrogen: OH− It has a charge of −1. ... R-phrases , , , , S-phrases , , , ,, , , , Flash point Non-flammable Related Compounds Related compounds Water Ozone Hydrazine Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in...


Significance

Catalysis is of paramount importance in the chemical industry. The production of most industrially important chemicals involves catalysis. The earliest commercial processes are the Haber process for ammonia synthesis and the Fischer-Tropsch synthesis. Research into catalysis is a major field in applied science, and involves many fields of chemistry, notably in organometallic chemistry, and physics. Catalysis is important in many aspects of environmental science, from the catalytic converter in automobiles to the causes of the ozone hole. Catalytic, rather than stoichiometric reactions are preferred in environmentally friendly green chemistry due to the reduced amount of waste generated. The Haber Process (also known as Haber–Bosch process) is the reaction of nitrogen and hydrogen to produce ammonia. ... For other uses, see Ammonia (disambiguation). ... Comparison between a clean Fischer-Tropsch diesel fuel (flask with clear liquid) and conventional No. ... n-butyllithium, an organometallic compound. ... Environmental science is the study of the interactions among the physical, chemical and biological components of the environment; with a focus on pollution and degradation of the environment related to human activities; and the impact on biodiversity and sustainability from local and global development. ... Catalytic converter on a Dodge Ram Van. ... Image of the largest antarctic ozone hole ever recorded in September 2000. ... In chemistry, stoichiometry is the study of the combination of elements in chemical reactions. ... Green chemistry is a chemical philosophy encouraging the design of products and processes that reduce or eliminate the use and generation of hazardous substances. ...


Notable examples

Estimates are that 90% of all commercially produced chemical products involve catalysts at some stage in the process of their manufacture.[1]


Manganese dioxide is used in the laboratory to prepare oxygen by the decomposition of hydrogen peroxide to oxygen and water. Manganese(IV) oxide (MnO2) is a chemical compound also known as manganese dioxide or manganese oxide. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... R-phrases , , , , S-phrases , , , ,, , , , Flash point Non-flammable Related Compounds Related compounds Water Ozone Hydrazine Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ...


Well-known applications of synthetic catalysts are:

Examples of catalysts that perform specific transformations on functional groups: Catalytic converter on a Dodge Ram Van. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... The Haber Process (also known as Haber–Bosch process) is the reaction of nitrogen and hydrogen to produce ammonia. ... For other uses, see Ammonia (disambiguation). ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... This article is about the chemistry of hydrogen. ... For other uses, see Iron (disambiguation). ...

These given examples show that different catalysts perform other transformations on the same functional groups, where the reaction would not proceed, proceed very slowly, or proceed in an unselective manner without the presence of the catalyst. A synonym for the more widely accepted term, alkene. ... A Ziegler-Natta catalyst is a reagent used in the production of unbranched, stereoregular vinyl polymers. ... This article does not cite any references or sources. ... Polypropylene lid of a Tic Tacs box, with a living hinge and the resin identification code under its flap Micrograph of polypropylene Polypropylene or polypropene (PP) is a thermoplastic polymer, made by the chemical industry and used in a wide variety of applications, including food packaging, ropes, textiles, stationery, plastic... Grubbs Catalyst is a transition metal carbene complex named after the chemist by whom it was first synthesized, Robert H. Grubbs. ... Olefin metathesis or transalkylidenation (in some literature, a disproportionation) is an organic reaction which involves redistribution of olefinic (alkene) bonds. ... A major route to Acetic acid is the rhodium-catalysed Monsanto process. ... The Wacker process or the Hoechst-Wacker process (named after the chemical companies of the same name) originally referred to the oxidation of ethylene to acetaldehyde by oxygen in the presence of a palladium(II) chloride catalyst. ... In organic chemistry, the Heck reaction or the Mizoroki-Heck reaction couples an unsaturated halide or triflate with an alkene in a basic solution. ...


The most common catalyst is the proton. Many transition metals and transition metal complexes are used in catalysis as well. In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... Synthesis of copper(II)-tetraphenylporphine, a metal complex, from tetraphenylporphine and copper(II) acetate monohydrate. ...


New directions - organocatalysis

While transition metal catalysts are well established, a new trend is toward organocatalysis which use comparatively simple organic molecules as catalysts. While typically, catalyst loading is much higher than transition metal-based catalysts, the catalysts are usually commercially available in bulk, helping to reduce costs drastically. Organocatalysts of the "new generation" are competitive to traditional metal-containing catalysts and are owing to low product inhibition applicable in substoichiometric quantities. The chemical character of organocatalysts offers new and attractive perspectives and advantages to synthetically working chemists. Nov. ... Justus von Liebigs synthesis of oxamide from dicyan and water represents the first organocatalytic reaction, with acetaldehyde further identified as the first discovered pure organocatalyst, which act similarly to the then-named ferments, now known as enzymes. ...


Catalytic processes

It has been suggested that this article or section be merged with Acid catalysis. ... Catalytic converter on a Dodge Ram Van. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... General Name, Symbol, Number rhodium, Rh, 45 Chemical series transition metals Group, Period, Block 9, 5, d Appearance silvery white metallic Standard atomic weight 102. ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... Comparison between a clean Fischer-Tropsch diesel fuel (flask with clear liquid) and conventional No. ... The Haber Process (also known as Haber–Bosch process) is the reaction of nitrogen and hydrogen to produce ammonia. ... For other uses, see Ammonia (disambiguation). ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... This article is about the chemistry of hydrogen. ... For other uses, see Iron (disambiguation). ... Hydrogenation is a class of chemical reactions which result an addition of hydrogen (H2) usually to unsaturated organic compounds. ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol (ethyl alcohol). ... The chemical compound nitric acid (HNO3), also known as aqua fortis and spirit of nitre, is an aqueous solution of hydrogen nitrate (anhydrous nitric acid). ... Petro redirects here. ... Alkylation is the transfer of an alkyl group from one molecule to another. ... In petroleum geology and chemistry, cracking is the process whereby complex organic molecules (e. ... Naphtha (CAS No. ... Steam reforming, hydrogen reforming or catalytic oxidation, is a method of producing hydrogen from hydrocarbons. ... In chemistry, a hydrocarbon is a cleaning solution consisting only of carbon (C) and hydrogen (H). ... Syngas (from synthesis gas) is the name given to gasses of varying composition that are generated in coal gasification and some types of waste-to-energy facilities. ... R-phrases S-phrases , , , Flash point Non-flammable Related Compounds Related strong acids Selenic acid Hydrochloric acid Nitric acid Related compounds Hydrogen sulfide Sulfurous acid Peroxymonosulfuric acid Sulfur trioxide Oleum Supplementary data page Structure and properties n, εr, etc. ... In organic chemistry, transesterification is the process of exchanging the alkoxy group of an ester compound by another alcohol. ... A Ziegler-Natta catalyst is a reagent used in the production of unbranched, stereoregular vinyl polymers. ...

See also

Catalysts and Catalysed Reactions (CCR) is a fully searchable online, text and graphical database that is updated weekly with the latest developments in catalysis. ... A single chemical reaction is said to have undergone autocatalysis, or be autocatalytic, if the reaction product is itself the catalyst for that reaction. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Enzyme catalysis is the catalysis of chemical reactions by enzyme molecules. ... // It had been a firmly established belief in biology that catalysis is reserved for proteins. ... Phase Boundary Catalysis (PBC) in chemistry is a type of heterogeneous catalytic system which facilitates the chemical reaction of a particular chemical component in immiscible phase react in an catalytic active site located at phase boundary. ... SUMO enzymatic cascade, designed and donated by Abgent. ...

References

  1. ^ "Recognizing the Best in Innovation: Breakthrough Catalyst". R&D Magazine, September 2005, pg 20.

External links

Look up Catalysis in
Wiktionary, the free dictionary.

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