4-Chlorobenzaldehyde

Chinese alias: 4-Chlorobenzaldehyde
English name: 4-Chlorobenzaldehyde
CAS: 104-88-1
MDL number: MFCD00003379
EINECS number: 203-247-4
RTECS number: CU5076000
BRN number: 385858
PubChem number: 24854064
Molecular formula: C7H5ClO
Molecular weight: 140.57
Physical property data
Appearance: Colorless to light yellow flaky crystals or powder. Density (g/mL, 25°C): 1.196 Relative density (25°C, 4°C): 1.19661 Melting point (°C): 48 Boiling point (°C, atmospheric pressure): 214 Refractive index at room temperature (n25): 1.55561 Refractive index: 1.5552 Flash point (°C): 87 Standard enthalpy of formation in crystalline phase (kJ·mol⁻¹): -146.4 Autoignition or ignition temperature (°C): 395
Solubility: Easily soluble in ethanol, ether, and benzene; soluble in water and acetone. Can volatilize with water vapor.
Synthesis methods
(1) Produced by chlorination and hydrolysis of p-chlorotoluene: Add p-chlorotoluene and phosphorus trichloride to the reaction vessel, heat to 155°C under light, and introduce chlorine gas. Control the temperature at 160-170°C, and introduce chlorine until the calculated amount is reached to obtain the chlorination liquid. Stir and add it to concentrated sulfuric acid, then stir at room temperature for 5 hours. Allow to stand for phase separation, take the lower layer liquid and place it in ice water for crystallization. Cool to below 5°C and filter. Wash the filter cake with ice water to obtain the crude product. Perform vacuum distillation and collect the fraction at 108-111°C (3.33 kPa) to obtain the final product.
(2) Manganese dioxide oxidation method for p-chlorotoluene: First, add p-chlorotoluene to the reaction vessel, then add 70% sulfuric acid, and slowly add manganese dioxide below 70°C. After completion, react for 0.5 hours, then perform steam distillation. Alternatively, p-chlorobenzaldehyde can also be obtained by air oxidation of p-chlorotoluene.
Main applications: Primarily used in the production of pharmaceutical raw materials and intermediates such as the sedative drug Fenarol and aminobutyric acid. In pesticides, it is used to produce chlorocinnamaldehyde and herbicides like Shadisan.