SORBIC ACID (2,4-hexadienoic acid) CH3 CH:CHCH:CHCOOH CAS:110-44-1 Properties:  White, crystalline solid; mp 134.5C; bp 228C (decomposes); 153C (50 mm); flash p (OC) 260F (126C); slightly soluble in water and many organic solvents.  Combustible. Derivation:  Trimerization of acetaldehyde and catalytic air oxidation of the resulting hexadienal.  Found in berries of mountain ash. Grade:  FCC, technical. Use:  Fungicide, food preservative (mold inhibitor), alkyd resin coatings, upgrading of drying oils, cold rubber additive, intermediate for plasticizers and lubricants.