Thioquinanthrene, also known as thiochinathren, is an aromatic organic chemical compound. It has the chemical formula C₁₈H₁₀N₂S₂ and reacts with

alcoholate Originally, an alcoholate was the crystalline form of a salt in which alcohol took the place of water of crystallization, such as nCl3(OC2H5)·C2H5OHsub>2 and C8H6N4O5·CH3OH. However this denomination should not be used anymore for the ending -a ...

s or alkoxides. One of the key uses is to act as a catalyst poison in the

Rosenmund reduction The Rosenmund reduction is a hydrogenation process in which an acyl chloride is selectively reduced to an aldehyde. The reaction was named after Karl Wilhelm Rosenmund, who first reported it in 1918. The reaction, a hydrogenolysis, is catalys ...

. It has the

IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...

name of 2,13-dithia-10,21-diazapentacyclo 2.8.0.0^3,12.0^4,9.0^15,20ocosa-1(14),3(12),4,6,8,10,15,17,19,21-decaene.

Rosenmund catalyst poison

In the Rosenmeund reaction, an

acid 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 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 group ...

. Continuing the reduction produces an

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 ...

. This further reaction is undesirable as the alcohol will now react with the acyl chloride to produce the unwanted

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 ...

product. For this reaction (over reduction) to be prevented, the catalyst needs to be poisoned. Thioquinanthrene was used initially, although other materials have been used since.

References

{{reflist Aromatic compounds Catalysis