2-Phenylacetamide (phenylacetamide, CAS 103-81-1) is an important pharmaceutical intermediate and organic synthesis raw material, widely used in the production of antibiotics, analgesics, pesticides and other fields.
1. Basic properties of 2-Phenylacetamide
(1) Physical and chemical properties
| Item | Parameters |
| Molecular formula | C₈H₉NO |
| Molecular weight | 135.16 g/mol |
| Appearance | White to off-white crystalline powder |
| Melting point | 156-158°C |
| Solubility | Slightly soluble in water, easily soluble in ethanol, acetone, chloroform |
| Stability | Stable at room temperature, avoid strong acids, strong bases, oxidants |
(2) Main application areas
● Pharmaceutical intermediates: used to synthesize penicillin antibiotics (such as amoxicillin) and analgesics (such as phenacetin).
● Pesticide synthesis: used as an intermediate for certain insecticides and herbicides.
● Organic synthesis: used to prepare derivatives such as phenylacetic acid and phenylacetonitrile.
2. Common problems and solutions
(1) Purity problem: high impurity content
Possible causes:
● Side reactions during the synthesis process (such as incomplete acylation).
● Improper storage leads to moisture absorption or oxidation.
Solution:
● Optimize the synthesis process (such as controlling the reaction temperature and improving the purity of the raw materials).
● Use recrystallization for purification (common solvent: ethanol/water mixed system).
● Strictly seal during storage and fill with inert gas (such as nitrogen).
(2) Agglomeration or discoloration
Possible causes:
● Moisture absorption leads to particle agglomeration.
● Light or high temperature triggers oxidation (yellow color).
Solution:
● Use moisture-proof packaging (such as aluminum foil bag + desiccant).
● Store in a cool and dark place (recommended temperature ≤25°C).
● Periodic testing (such as sampling every 6 months to check appearance and purity).
(3) Poor solubility, affecting reaction efficiency
Possible causes:
● Crystal morphology affects dissolution rate. Improper solvent selection (e.g. low solubility in water).
Solutions:
● Heat to dissolve (60°C in ethanol or DMF improves solubility).
● Use ultrasound to assist dissolution (suitable for small-scale experiments).
● Use polar solvents (e.g. acetone, DMSO).
