Rosenmund reduction
   HOME

TheInfoList



OR:

The Rosenmund reduction is a
hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a Catalysis, catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or S ...
process in which an
acyl chloride In organic chemistry, an acyl chloride (or acid chloride) is an organic compound with the functional group . Their formula is usually written , where R is a side chain. They are reactive derivatives of carboxylic acids (). A specific example o ...
is selectively reduced to an
aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...
. The reaction was named after
Karl Wilhelm Rosenmund Karl Wilhelm Louis Rosenmund (15 December 1884 – 8 February 1965) was a German chemist. He was born in Berlin and died in Kiel. Rosenmund studied chemistry and received his Ph.D. 1906 from University of Berlin for his work with Otto Diels. He ...
, who first reported it in 1918. The reaction, a
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. ...
, is catalysed by
palladium Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself na ...
on
barium sulfate Barium sulfate (or sulphate) is the inorganic compound with the chemical formula Ba SO4. It is a white crystalline solid that is odorless and insoluble in water. It occurs as the mineral barite, which is the main commercial source of barium an ...
, which is sometimes called the Rosenmund catalyst. Barium sulfate has a low surface area which reduces the activity of the palladium, preventing over-reduction. However, for certain reactive acyl chlorides the activity must be reduced further, by the addition of a
poison Poison is a chemical substance that has a detrimental effect to life. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figuratively, with a broa ...
. Originally this was
thioquinanthrene Thioquinanthrene, also known as thiochinathren, is an aromatic organic chemical compound. It has the chemical formula C18H10N2S2 and reacts with alcoholates or alkoxides. One of the key uses is to act as a catalyst poison in the Rosenmund reduct ...
although
thiourea Thiourea () is an organosulfur compound with the formula and the structure . It is structurally similar to urea (), except that the oxygen atom is replaced by a sulfur atom (as implied by the ''thio-'' prefix); however, the properties of urea ...
has also been used. Deactivation is required because the system must reduce the acyl chloride but not the subsequent aldehyde. If further reduction does take place it will create a primary alcohol which would then react with the remaining acyl chloride to form an
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 ...
. Rosenmund catalyst can be prepared by reduction of palladium(II) chloride solution in the presence of BaSO4. Typical reducing agent is formaldehyde. While Rosenmund reduction method can be used to prepare several aldehydes, formaldehyde cannot be prepared, as formyl chloride is unstable at room temperatures.


See also

*
Lindlar catalyst A Lindlar catalyst is a heterogeneous catalyst that consists of palladium deposited on calcium carbonate or barium sulfate which is then poisoned with various forms of lead or sulfur. It is used for the hydrogenation of alkynes to alkenes (i.e. ...
- Palladium on calcium carbonate with added catalytic poison, similar to the Rosenmund catalyst *
Grundmann aldehyde synthesis The Grundmann aldehyde synthesis is a chemical reaction that produces an aldehyde from an acyl halide.Grundmann, C. ''Ann.'' 1936, ''524'', 31. Because of the Rosenmund reduction and DIBAL-H accomplish similar transformations, this reaction sequ ...
- Also reduces an acyl halide to an aldehyde, via the use of diazomethane *
Diisobutylaluminium hydride Diisobutylaluminium hydride (DIBALH, DIBAL, DIBAL-H or DIBAH) is a reducing agent with the formula (''i''-Bu2AlH)2, where ''i''-Bu represents isobutyl (-CH2CH(CH3)2). This organoaluminium compound is a reagent in organic synthesis. Properties Like ...
(DIBALH) can also reduce acid chlorides to aldehydes. *
Stephen aldehyde synthesis Stephen aldehyde synthesis, a named reaction in chemistry, was invented by Henry Stephen ( OBE/MBE). This reaction involves the preparation of aldehydes (R-CHO) from nitriles (R-CN) using tin(II) chloride (SnCl2), hydrochloric acid (HCl) and que ...
- Nitriles to aldehydes via reduction


References


Further reading

* * {{cite journal , author = Saytzeff, M. , title = Ueber die Einwirkung des vom Palladium absorbirten Wasserstoffes auf einige organische Verbindungen , year = 1873 , journal = Journal für Praktische Chemie , volume = 6 , issue = 1 , pages = 128–135 , doi = 10.1002/prac.18730060111, url = https://zenodo.org/record/1427856 Organic redox reactions Name reactions