Acetophenone oxime preparation

Objective

to obtain and characterize an oxime (acetophenone oxime) by reacting acetophenone with hydroxylamine hydrochloride in the presence of sodium acetate and ethanol.

Acetophenone oxime preparation
Acetophenone oxime preparation

Background

Oximes are organic compounds that contain the functional group -C=N-OH. They are synthesized by the reaction of a carbonyl compound (>C=O) with hydroxylamine NH2OH or its derivatives. The resulting product is an addition product, which undergoes dehydration to form the oxime.

Acetophenone oxime is one of the commonly synthesized oximes in chemical laboratories. It is synthesized by reacting acetophenone with hydroxylamine hydrochloride in the presence of a base (NaOAc) and ethanol.

Experimental procedure

To prepare the oxime, first, dissolve the acetophenone (1.2 g, 10 mmol) in 20 mL of EtOH in a 50 mL round‐bottom flask. Then, add the hydroxylamine hydrochloride NH2OH·HCl (1.18 g, 17 mmol) and sodium acetate trihydrate (0.82 g, 10 mmol), which should already be dissolved in 15 mL of warm water, to the flask.

Heat the mixture under reflux on a water bath for 20 minutes. After that, quickly filter the hot solution through a fluted filter paper. To collect the crystalline oxime (a white crystalline solid), cool the filtrate in an ice bath and filter it under vacuum. Wash the crystals with a small volume of cold 50 % EtOH and dry them on the filter with suction. Finally, record the yield and melting point of the product.

Physico-chemical properties

This table collects data for the molecular weight (Mw), melting point (M.p.) boiling point (B.p.) and density of the reactives and compounds used in this laboratory experiment.

Name Mw (g/mol) M.p. (ºC) B.p. (ºC) Density (g/ml)
Acetophenone 120.15 19-20 202 1.03
Hydroxylamine hydrochloride 69.49 155-157 - 1.670
Sodium acetate trihydrate 136.08 - - -
EtOH 46.07 -114.1 78.5 0.790
Acetophenone oxime 135.16 55-60 118-120 1.110

GHS pictograms

Hazard pictograms form part of the international Globally Harmonized System of Classification and Labelling of Chemicals (GHS) and are collected in the followinf Table for the chemical compounds used in this experiment.

Name GHS
Acetophenone ghs08  Danger Warning Systemic health hazards pictogram
Hydroxylamine hydrochloride ghs08  Danger Warning Systemic health hazards pictogram ghs05  Danger Warning Corrosive cat. 1 pictogram ghs07  Warning Toxic cat. 4 Irritant cat. 2 or 3 Lower systemic health hazards pictogram ghs09  Warning (for cat. 1) (for cat. 2 no signal word) Environmental hazard pictogram
Sodium acetate trihydrate Non-hazardous
EtOH ghs02  Danger Warning Flammable pictogram
Acetophenone oxime ghs05  Danger Warning Corrosive cat. 1 pictogram ghs07  Warning Toxic cat. 4 Irritant cat. 2 or 3 Lower systemic health hazards pictogram

International Chemical Identifier

The IUPAC InChI key identifiers for the main compounds used in this experiment are provided to facilitate the nomenclature and formulation of chemical compounds and the search for information on the Internet for these compounds.

Acetophenone KWOLFJPFCHCOCG-UHFFFAOYSA-N
Hydroxylamine hydrochloride WTDHULULXKLSOZ-UHFFFAOYSA-N
Sodium acetate trihydrate AYRVGWHSXIMRAB-UHFFFAOYSA-M
EtOH LFQSCWFLJHTTHZ-UHFFFAOYSA-N
Acetophenone oxime JHNRZXQVBKRYKN-VQHVLOKHSA-N

References

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