CHE 233 Final| 65 Questions | With Complete Solutions

What are saturated vs unsaturated fatty acids? correct answer: •Saturated fatty acids have no C=C bonds (their C's have max # of Hs) •Unsaturated fatty acids have one or more C=C bonds (monosaturated = one double bond) (polyunsaturated = more than 1 double bond) •Z (cis) are naturally occurring double bonds; E (trans) are artificial double bonds How is biodiesel produced commercially? Which method is predominant? correct answer: ***1) Base catalyzed transesterification of oil with alcohol 2) Acid catalyzed esterification of the oil with methanol 3) Saponification of the oil to yield free fatty acids, followed by acid catalyzed esterification Transesterification correct answer: conversion of one ester into another through a substitution reaction with an alcohol (alkoxy group) reaction transesterification correct answer: ester 1 + alcohol--> ester 2 Making Biodiesel FAMEs correct answer: Triglyceride --> in CH3OH & catalytic CH3O- Na+--> FAMEs What does FAME and NMR stand for? correct answer: •FAME: Fatty acid methyl esters •NMR: Nuclear Magnetic Resonance In biodiesel lab, what is the limiting reagent? Which reagent is in excess and why is it required in excess? correct answer: •L.R. is triglyceride •Methanol is the reagent required in excess so equilibrium can be shifted to the right to produce more product In biodiesel lab, what is the effect of water on sodium methoxide? correct answer: NaOMe + H2O -> MeOH + NaOH In biodiesel lab, how will the product be characterized? correct answer: •H-NMR •Prominent peak due to -OCH3; singlet at 4.1 ppm •Lack of glyceryl hydrogens; lack of multiplet at 4.0 - 4.4 ppm In biodiesel lab, how is waste disposed? correct answer: •Organic liquid hazardous waste container NMR Peaks correct answer: In biodiesel lab, how is Le-Chatelier's principle applicable to the transesterification reaction in the preparation of FAMEs? correct