Decalins

Decalins are a class of organic compounds that are saturated derivatives of naphthalene. The name "decalin" is derived from decahydronaphthalene, indicating that ten hydrogen atoms have been added to the naphthalene molecule. Structurally, decalins consist of two fused six-membered rings, where each ring contains no double bonds. This saturation gives decalins properties distinct from their aromatic precursor.

There are two principal stereoisomers of decalin: cis-decalin and trans-decalin. These isomers differ in the relative orientation of the hydrogen atoms at the bridgehead carbon atoms where the two rings are fused. In cis-decalin, the hydrogen atoms are on the same side of the fused ring system, while in trans-decalin, they are on opposite sides. This difference in stereochemistry leads to variations in their physical properties such as melting point and boiling point.

Decalins are colorless liquids with a characteristic odor. They are relatively stable compounds and are less reactive than unsaturated hydrocarbons. Due to their saturated nature and fused ring structure, decalins are nonpolar molecules and are therefore soluble in many organic solvents but insoluble in water. They are used as solvents in various applications, including as solvents for resins, fats, and oils. They can also serve as starting materials or intermediates in the synthesis of other organic compounds.