Copper chromite is an

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

with the formula Cu₂Cr₂O₅. It is a black solid that is used to catalyze reactions in

organic synthesis Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...

History

The material was first described in 1908. The catalyst was developed in North America by

Homer Burton Adkins Homer Burton Adkins (16 January 1892 – 10 August 1949) was an American chemist who studied the hydrogenation of organic compounds. Adkins was regarded as top in his field and a world authority on the hydrogenation of organic compounds. Adki ...

and Wilbur Arthur Lazier, partly based on interrogation of

German German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...

chemists after

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

in relation to the

Fischer–Tropsch process The Fischer–Tropsch process is a collection of chemical reactions that converts a mixture of carbon monoxide and hydrogen, known as syngas, into liquid hydrocarbons. These reactions occur in the presence of metal catalysts, typically at temperat ...

. For this reason it is sometimes referred to as the Adkins catalyst or the Lazier catalyst.

Chemical structure

The compound adopts a

spinel Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , which means ''spine'' in reference to its pointed crystals. Properties S ...

structure. The

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

s for the constituent metals are Cu(II) and Cr(III). A variety of compositions are recognized for the substance, including Cu₂CrO₄·CuO·BaCrO₄ ( CAS# 99328-50-4) and Cu₂Cr₂O₅ (CAS# 12053-18-8). Commercial samples often contain barium oxide and other components.

Production

Copper chromite is produced by

thermal decomposition Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is req ...

of one of three substances. The traditional method is by the

ignition Ignition may refer to: Science and technology * Firelighting, the human act of creating a fire for warmth, cooking and other uses * Combustion, an exothermic chemical reaction between a fuel and an oxidant * Fusion ignition, the point at which a ...

of copper chromate: : 2 → 2 + Copper barium ammonium chromate is the most commonly used substance for production of copper chromite. The resulting copper chromite mixture produced by this method can only be used in procedures that contain materials inert to

barium Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Th ...

, as barium is a product of the decomposition of copper barium ammonium chromate, and is thus present in the resulting mixture. The by-product

copper oxide Copper oxide is a compound from the two elements copper and oxygen. Copper oxide may refer to: * Copper(I) oxide (cuprous oxide, Cu2O) * Copper(II) oxide Copper(II) oxide or cupric oxide is an inorganic compound with the formula CuO. A black so ...

is removed using an

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component ...

extraction, consisting of washing with the acid,

decantation Decantation is a process for the separation of mixtures of immiscible liquids or of a liquid and a solid mixture such as a suspension. The layer closer to the top of the container—the less dense of the two liquids, or the liquid from which th ...

and then heat drying of the remaining solid to yield isolated copper chromite. Copper chromite is produced by the exposure of copper barium ammonium chromate to temperatures of 350-450 °C, generally by a

muffle furnace A muffle furnace or muffle oven (sometimes retort furnace in historical usage) is a furnace in which the subject material is isolated from the fuel and all of the products of combustion, including gases and flying ash. After the development of ...

: : → + CuO + 2 Ba + 4 + 4 Cr + + 6 Copper ammonium chromate is also used for production of copper chromite. It is generally utilized as an alternative to the route of barium ammonium chromate for usage in chemicals reactive with barium. This can also be washed with acetic acid and dried to remove impurities. Copper chromite is produced through the exposure of copper ammonium chromate to temperatures of 350-450 °C: : → + CrO + 4 + An active copper chromite catalyst which includes

in its structure can be prepared from a solution containing

barium nitrate Barium nitrate is the inorganic compound with the chemical formula Ba( NO3)2. It, like most barium salts, is colorless, toxic, and water-soluble. It burns with a green flame and is an oxidizer; the compound is commonly used in pyrotechnics. Man ...

copper(II) nitrate Copper(II) nitrate describes any member of the family of inorganic compounds with the formula Cu( NO3)2(H2O)x. The hydrates are blue solids. Anhydrous copper nitrate forms blue-green crystals and sublimes in a vacuum at 150-200 °C. Common hy ...

, and ammonium chromate. When these compounds are mixed a resulting precipitate is formed. This solid product is then

calcine Calcination refers to thermal treatment of a solid chemical compound (e.g. mixed carbonate ores) whereby the compound is raised to high temperature without melting under restricted supply of ambient oxygen (i.e. gaseous O2 fraction of air), gener ...

d at 350–400 °C to yield the catalyst: : Cu(NO₃)₂ + Ba(NO₃)₂ + (NH₄)₂CrO₄ → CuCr₂O₄·BaCr₂O₄

Illustrative reactions

Hydrogenolysis Hydrogenolysis is a chemical reaction whereby a carbon–carbon or carbon–heteroatom single bond is cleaved or undergoes lysis (breakdown) by hydrogen.Ralph Connor, Homer Adkins. Hydrogenolysis Of Oxygenated Organic Compounds. J. Am. Chem. Soc. ...

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

compounds to the corresponding

alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...

s, and carbon–carbon and carbon–oxygen double bonds to single bonds. For example, sebacoin, derived from the

acyloin condensation Acyloin condensation is a reductive coupling of two carboxylic esters using metallic sodium to yield an α-hydroxyketone, also known as an acyloin. The reaction is most successful when ''R'' is aliphatic and saturated. The reaction is performe ...

of dimethyl sebacate, is hydrogenated to 1,2-cyclodecanediol by this catalyst.

Phenanthrene Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) with formula C14H10, consisting of three fused benzene rings. It is a colorless, crystal-like solid, but can also appear yellow. Phenanthrene is used to make dyes, plastics and pesticides, e ...

is also reduced, at the 9,10 position. *

tetrahydrofurfuryl alcohol Tetrahydrofurfuryl alcohol (THFA) is an organic compound with the formula HOCH2C4H7O. In terms of its structure, it consists of a tetrahydrofuran ring substituted in the 2-position with a hydroxymethyl group. It is a colorless liquid that is use ...

to 1,5-pentanediol at 250–300 °C under 3300-6000 psi of H₂. *

Decarboxylation Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is t ...

of α-phenylcinnamic acid to ''cis''-

stilbene Stilbene may refer to one of the two stereoisomers of 1,2-diphenylethene: * (''E'')-Stilbene (''trans'' isomer) * (''Z'')-Stilbene (''cis'' isomer) See also * Stilbenoids, a class of molecules found in plants * 1,1-Diphenylethylene 1,1-Diphenyl ...

. Reactions involving hydrogen are conducted at relatively high gas pressure (135 atm) and high temperatures (150–300 °C) in a so-called hydrogenation bomb. More active catalysts, such as W-6 grade Raney nickel, also catalyze hydrogenations such as

ester reduction In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

s. The latter catalyst benefits from requiring less vigorous conditions (i.e., it works at room temperature under similar hydrogenation pressures) but requires the chemist to use a higher ratio of catalyst to

reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

References

External links

* CAS registry 440-47-3& 317-38-0 {{Organic reactions Reagents for organic chemistry Copper(II) compounds Hydrogenation catalysts Chromium(III) compounds Chromium–oxygen compounds Substances discovered in the 1900s