CHE 233 FINAL UKY QUESTIONS WITH COMPLETE SOLUTION

What is biodiesel correct answer: a fuel comprising long-chain fatty acid methyl esters (FAMEs) derived from vegetable oils or animal fats, designated B100 and meeting standard requirements. What methods can be used to make fatty acid methyl esters (FAME's)? correct answer: -Base-catalyzed transesterification -Acid-catalyzed esterification -Saponification of the oil to yield free fatty acids, followed by acid catalyzed esterification What are fatty acids? correct answer: carboxylic acids (R-COH) whose unbranched non-polar hydrocarbon R-group is 8-18 carbon atoms long. What are unsaturated fatty acids? correct answer: fatty acids with one or more double bonds in the chains What are saturated fatty acids? correct answer: fatty acids with NO double bonds in the chains How are triglycerides produced ? correct answer: Biosynthesized by phosphorylated glycerol and enzyme functionalized fatty acid esters. ENZYMATIC TRANSESTERIFICATION What is transesterification correct answer: transformation of an ester into another ester through interchange of the alkoxy group. Why is base-catalyzed transesterification usually preferable ? correct answer: Relatively low reaction temperature, Rapid and efficient conversion (98%) with minimal side reactions, No need for exotic starting materials, Faster than acid-catalyzed. Bases typically used are less corrosive than the acids required for acid catalyzed production. What base catalyst can be used in transesterification ? correct answer: Alkaline metal hydroxides (e.g. KOH and NaOH) OR Non-ionic (organic) bases What is an advantage to using metal hydroxides like KOH over non-ionic organic bases like NaOMe? correct answer: Metal hydroxides are cheaper than non-ionic organic bases and give higher conversions.