Pentanal (also called valeraldehyde) is the

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

is an

alkyl In organic chemistry, an alkyl group is an alkane missing one hydrogen. The term ''alkyl'' is intentionally unspecific to include many possible substitutions. An acyclic alkyl has the general formula of . A cycloalkyl is derived from a cycloa ...

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 gro ...

, molecular formula C₅H₁₀O. It is used in flavorings, resin chemistry, and rubber accelerators. Its smell is described as fermented, bready, fruity, nutty, berry.

Production

Pentanal is obtained by

hydroformylation Hydroformylation, also known as oxo synthesis or oxo process, is an industrial process for the production of aldehydes from alkenes. This chemical reaction entails the net addition of a formyl group (CHO) and a hydrogen atom to a carbon-carbon ...

butene Butene, also known as butylene, is an alkene with the formula . The word ''butene'' may refer to any of the individual compounds. They are colourless gases that are present in crude oil as a minor constituent in quantities that are too small for ...

. Also C4 mixtures can be used as starting material like the so-called raffinate II, which is produced by

steam cracking Steam cracking is a petrochemical process in which saturated hydrocarbons are broken down into smaller, often unsaturated, hydrocarbons. It is the principal industrial method for producing the lighter alkenes (or commonly olefins), including et ...

and contains (''Z'')- and (''E'')-2-butene,

1-butene 1-Butene (or 1-Butylene) is the organic compound with the formula CH3CH2CH=CH2. It is a colorless gas that is easily condensed to give a colorless liquid. It is classified as a linear alpha-olefin. It is one of the isomers of butene (butylene). ...

butane Butane () or ''n''-butane is an alkane with the formula C4H10. Butane is a gas at room temperature and atmospheric pressure. Butane is a highly flammable, colorless, easily liquefied gas that quickly vaporizes at room temperature. The name but ...

and

isobutane Isobutane, also known as ''i''-butane, 2-methylpropane or methylpropane, is a chemical compound with molecular formula HC(CH3)3. It is an isomer of butane. Isobutane is a colourless, odourless gas. It is the simplest alkane with a tertiary carbo ...

. The conversion to the product is accomplished with

synthesis gas Syngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide, in various ratios. The gas often contains some carbon dioxide and methane. It is principly used for producing ammonia or methanol. Syngas is combustible and can be used ...

in the presence of a

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

consisting of a rhodium-bisphosphite complex and a

sterically hindered Steric effects arise from the spatial arrangement of atoms. When atoms come close together there is a rise in the energy of the molecule. Steric effects are nonbonding interactions that influence the shape ( conformation) and reactivity of ions ...

secondary amine with a selectivity toward pentanal of at least 90%.Patent WO 2009/146985 der Evonik Oxeno GmbH

Use

Pentanal is used in diverse flavors (e. g. fruit flavors) and as a

vulcanization Vulcanization (British: Vulcanisation) is a range of processes for hardening rubbers. The term originally referred exclusively to the treatment of natural rubber with sulfur, which remains the most common practice. It has also grown to includ ...

accelerator. 2-Propyl-2-heptenal is obtained from pentanal by aldol condensation, which is

hydrogenated Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic ...

to the saturated branched 2-propylheptanol. This alcohol serves as a starting material for the PVC

plasticizer A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture. Plasticiz ...

di-2-propylheptyl phthalate (DPHP). Valeraldehyde is oxidized to give

valeric acid Valeric acid or pentanoic acid is a straight-chain alkyl carboxylic acid with the chemical formula . Like other low-molecular-weight carboxylic acids, it has an unpleasant odor. It is found in the perennial flowering plant ''Valeriana officin ...

.{{Ullmann, first1=Wilhelm, last1=Riemenschneider, title=Carboxylic Acids, Aliphatic, year=2002, doi=10.1002/14356007.a05_235

References

Alkanals