salicylic acid

Topics: Carboxylic acid, Salicylic acid, Acetic acid Pages: 3 (824 words) Published: October 14, 2013

Synthesis of Salicylic Acid

Experimental Data:
1. Mass of methyl salicylate used: 0.232 g
2. Theoretical yield of salicylic acid: 0.211 g
3. Volume H2SO4 added, with units (drops or mL): 3mL
4. Mass of crude salicylic acid obtained: 0.250 g
5. Volume of water used as recrystallizing solvent: 2 mL
6. Mass of purified salicylic acid: 0.134 g
7. Percent yield of purified salicylic acid from reaction: 63.5% 8. Melting point of purified product: 158-160 oC
9. Name of NMR solvent used and its chemical shifts: Acetone-d6, the chemical shifts are 29.9 and 206.7 for 13C

Questions:

1.

2. The phenol group of methyl salicylate is a weak acid, therefore it reacts very swiftly with a strong base, in this case NaOH, to form a sodium salt. Which removes the H from the phenol group. During hydrolysis the ester group of methyl salicylate is broken apart by the addition of a molecule of water. From which a molecule of alcohol and a molecule of carboxylic acid are obtained. The strong basic reaction mixture causes the carboxylic acid to react very quickly, which causes the formation of the carboxylate anion, in this case a dianion. From this process it can be said that the product can exist as a dianion before the addition sulfuric acid. .

3. a.
.250g × 100mL = 25g/mL 13.9mL ÷100mL =.139 .2502g - .03197g= .2182g 25g/mL ÷1.8 g = 13.9 mL .139 ×0.23 g = .03197 g (.2182 ÷ .2502) × 100 = 87.2% 13.9mL ÷ 100 mL= .139

.139×1.8g = .2502 g

b.
.250g × 100mL = 25g/mL 6.8mL ÷ 100mL =.068.2516g ­ .01564g = .2360g 25g/mL ÷ 3.7g = 6.8mL .068 × .23g = .01564 g(.2360 ÷ .2516)× 100 =93.8% 6.8mL ÷ 100mL = .068

.068 × 3.7g = .2516g

c.
.250g × 100mL = 25g/mL 6.8mL ÷ 100mL =.068.2516g - .00884g = .2427g
25g/mL ÷ 3.7g =6.8mL .068 × .13g =...
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