NITRILE 1. SYNTHESIS oF VERATRALDEHYDE oxiME Review From previous lab procedures
ID: 498422 • Letter: N
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NITRILE 1. SYNTHESIS oF VERATRALDEHYDE oxiME Review From previous lab procedures: suction filtration, recrystallization From organic chemistry text: sections 18.15, 18.16 Introduction oximes are usually prepared as derivatives of aldehydes and ketones, and they are used as a means of characterizing them and them. However, be reduced to amines or dehydrated to yield nitriles. Thus, they are also useful intermediates for the conversion of aldehydes or ketones to amines and nitriles. OCH, Although you learned about another dehydration reaction that also leads to nirtiles ion of amides by Paolo (Wade, p.985), today's experiment requires less stringent reaction conditions (lower temperature, simpler reaction set-up, less energy use, etc) and therefore, it is more suitable for an introductory organic chemistry laboratory experiment. PARTI. Synthesis of veratraldehyde oxime N OH H2NOH Safety observe the general safery precautions outlined in the section SAFETY in the ORGANIC LAB. In addition to the general safety measures, the special safery precautions for this specific experiment are as follows: ne hydrochloride is toxic and corrosive. Avoid contact with skin, Sodium hydroxide is castic. Avoid contact with skin and clothing. Hydrochloric acid is corrosive. Avoid contact with skin and clothing Prepare a solution of 4.0 g of varetraldehyde in 10 mL of warm ethanol in a 50-mL round-bottomed flask equipped with a condenser. In a test tube dissolve hydroxylamine hydrochloride in 5 mL of water. Add the hydroxylamine solution to the aldehyde solution and mix the contents, In another test tube. dissolve 1.5 sodium hydroxide in 2 mL of water. Cautiously add the sodium hydroxide solution to the round-bottomed flask. Using a Thermowell, heat the RB flask to a gentle boil for 30 minutes. After the reaction time is up, prepare an ice-Hcl mixture by placing about 2 inches of ice in a 150-mL beaker and add 0,5 ml of concentrated HCI to the ice. Carefully swirl the contents. Remove from the R.B. allow the contents to cool for 3.4 minutes heat mixture. Stir the contents and then pour the mixture over the well. Copyright 2015Explanation / Answer
Questions : Before Lab
BL1 : the conversion of aldehyde to oxime can be monitored with IR spectroscopy.
In IR, a strong streching frequency corresponding to C=O group is seen at about 1710 cm-1 which vanishes when oxime is formed in the reaction.
BL2 : NaOH is added to neutralize HCl present in NH2OH.HCl reagent.
theoretical yield of varetraldehyde oxime
= (4 g/166.18 g/mol) x 181.191
= 4.36 g
This is If all of varetraldehyde is converted into xime derrivative
Percent yield for the reaction = (actual yield from reaction/theoretical yield) x 100
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