Question

account for the use of the different solvents in the purification of 2. hint. think about how solvent polarity and solubility are related

flask In a 100-ml round bottom three-necked flask with 14/20 joints is placed 1.4 g of boric acid and 3 ml. of triethanolamine (p1.124 g ml.") together with a magnetic stirring bar. Toluene (40 ml) is then added and the two side necks are closed with 14/20 glass stoppers (or rubber septa). In the central neck is placed a three-way adapter head connected to a West condenser, a receiver adapter, and a receiver flask. Close the three-way head with a ground glass joint thermometer and heat the mixture to the boiling point with an electric heating mantle while stirring with a magnetic stirrer. Initially set the Variac to ca. 50. The first liquid to be distilled is the toluene-water azeotrope (constant boiling mixture) as the toluene is used to remove the water produced in the reaction. This liquid will separate into water and toluene phases as it cools in the condenser and receiver. When the temperature rises to 105 °C and no further separation of water is observed the reaction is complete. Stop the distillation, replace the three-way head with a stopcock (or rubber septa) and allow the Mask to cool. After cooling, remove and filter the product, and wash with 20 mL of dry toluene. When dry, grind to a rough powder using a mortar and pestle. Dissolve the residue in CHCl and gravity filter. Addition of hexane will precipitate the product (2), which can be collected via vacuum filtration. • Obtain the IR spectrum of 2 as a cast film (CH2Cl). Be sure to annotate any significant peaks. Obtain the 'H and C NMR spectra of 2 (CDC) solution).

Answer 1

1. The chemical reaction of formation of compound 2

PASS NO DATE Chami Cal reaeticn NENEN ONSBlOHs Taluane Pacinet 2 Trietheardamine torate

2. IR analysis of compound 2:

The compound 2 is triethanolamine borate,

The IR values in cm-1: Th e peak at 1372cm-1，1345 cm-1,1261 cm-1are characteristic absorption peaks of B-O, a typical absorption of –CH2 at 2853cm-1 was observed, C-O and C-N are corresponding with the IR absorption peak at 1083cm-1, 1028cm-1

3. 1HNMR（400MHz，CDCl3），δ=3.078（t，J=6.0Hz，2H，OCH2CH2N），δ=3.952（t，J=5.6Hz ，2H，OCH2CH2N）

The peak at 3.078 is triplet duet o -OCH2 and the peak at 3.952 is triplet due to -NCH2

4. 13CNMR（400MHz，CDCl3） showed characteristic peaks at

δ=59.27（OCH2CH2N) peak due to 3 carbon from -CH2N,

δ=61.94（OCH2CH2N） peak due to 3 carbon from -OCH2