Question

2. Below are FTIR spectra for cellulose nanocrystals (CNC, blue) and cellulose nanocrystals after a surface modification by TEMPO oxidation (O-CNC, orange) a. What functional group does the peak that appears in the orange curve correspond with? b. As you increase the extent of surface modification, what will happen to the peak at approx. 1600 cm1? What will happen to the peak at approx. 1000 cm1? O-CNC CNC 800 1300 1800 Wav Transmission

Answer 1

Oxidation reactions are performed on cellulose to introducecarboxylic acid or aldehyde functionalities.he two mostcommon methodologies are nitroxyl based oxidation to producecarboxylic acids selectively at primary alcohols and periodateoxidation to produce aldehydes from vicinal diols.2,2,6,6-Tetramethylpiperidinyloxyl radical (TEMPO) oxidation of cellu-lose has become popular both as a surface modication and abulk technique.Generally, the oxidation is carried outwith a catalytic amount of TEMPO with a secondary oxidantsuch as sodium hypochlorite or sodium chlorite to recycle theTEMPO Sodium bromide is quite used toincrease the rate of oxidation through formation of sodiumhypobromite.

In by the process of surface modification, TEMPO oxidation of (CNC) - - aldehyde ? Alcohols become efter aad oxidation @ functie functional groups & Aldehyde Carboxylic and acid when we increase the extent of Surface modification the secondary oxidation will take place and Aldehyde become and oxidation -oh- on Aldehyde oxidation - Acid