It can be chemically synthesized by the reaction between benzoic acid with sodium bicarbonate, sodium carbonate, or sodium hydroxide.
Here is the brief manufacturing process came up by the China top manufacturer Tianjin Dongda (1):
Obtaining crude sodium benzoate by the neutral reaction between benzoic acid and sodium hydroxide at pH 7.5-8.0
Decolorizing, filtering, palletizing and drying
Here is the reaction equation:
C6H5COOH + NaOH = C6H5COONa + H2O
By the way, benzoic acid can be produced by the reaction between sodium benzoate and hydrochloric.
Powder and Granular
Powder and granular are two common forms of sodium benzoate, but the powdered form is easy to caking in storage and transportation due to its hygroscopicity and poor fluidity.