Chemistry

21. Two-step synthesis

  • 01:00 What forms when the temperature is above 10oC? 
  • 01:10 Why the need to wash the product with ethanol?
  • 01:14 Why the need to use a minimum volume of hot methanol?
  • 02:09 What’s the reason for adding acid at this stage?
  • 02:23 Why use only a minimum volume of HCl?
  • 02:31 How do you know how pure your sample is?
  • 02:37 What affects percentage yield?

  • cold de-ionised water

  • digital balance (pref. 3-d.p but minimum 2-d.p.)

  • access to ice

  • spatula

  • weighing-boat

  • 2 x 100 cm3 conical flask

  • 25 cm3 measuring cylinder

  • ice-bath

  • glass Pasteur pipette with rubber teat

  • glass stirring rod

  • 250 cm3 beaker

  • buchner funnel + suction apparatus

  • filter paper

  • 10 cm3 measuring cylinder

  • hot water-bath

  • round-bottomed flask or pear-shaped flask

  • reflux condenser

  • thermometer

  • sample vial

  • labels / fine-tipped permanent marker

  • anti-bumping granules

  • heating mantle / Bunsen burner with water-bath

  • clamp-stand, clamp, boss

  • melting-point apparatus / Thiele tube

  • capillary tube

Hazard Risk Control measure

Conc. H2SO4 solution – corrosive.

Contact with eyes & skin

Eye: flood with tap-water (10min). See doctor.

Skin: remove excess with dry towel. Drench with water

Methylbenzenecarboxylate (C6H5COOCH3) – irritant.

Ignite close to flame.

Extinguish using fire-blanket

Conc. HNO3 solution- corrosive

Contact with eyes & skin.

Eye: flood with tap-water
(10min). See doctor. Skin:
remove excess with dry
towel. Drench with water.

Methanol (CH3OH) – flammable, acute toxicity, serious health hazard.

Ignite close to flame. Contact with skin/eyes or swallowed.

Extinguish using fire-blanket.
Skin: wash area with water.
Eye: flood with tap-water
(10min). See doctor.
Swallow: wash mouth with
water. Don’t induce
vomitting. Sips of water help
cool throat. See doctor.

Solid sodium hydroxide – corrosive.

Contact with skin & eyes.

Eye: flood with tap water
(20min). See doctor and
continue washing eye during
journey in ambulance.

Skin: drench with water

Conc. HCl solution – corrosive

Contact with skin & eyes

Skin: remove excess with dry towel. Drench with water. Eye: flood with tap water (10min). See doctor

0.1 mol dm-3 HCl solution – no hazard.

Contact with skin & eyes.

Skin: drench with water.

Eye: flood with tap water (10min).