Is the production process of HEDP•Na4 complex?

Yes, the production process of HEDP•Na₄ (Tetrasodium hydroxyethylidene diphosphonate) is indeed a multi-step chemical process that typically follows the synthesis of HEDP acid, involving neutralization, purification, and crystallization. Below is a detailed breakdown of the production process, key steps, and technical considerations.

1. Overview: From HEDP Acid to HEDP•Na₄

HEDP•Na₄ is the tetrasodium salt of HEDP acid. Its production generally consists of two main stages:

Synthesis of HEDP acid (the active acidic form).

Neutralization and purification to obtain the high-purity sodium salt.

2. Detailed Production Process

Stage 1: Synthesis of HEDP Acid

The most common industrial method is the phosphonation reaction using phosphorus trichloride (PCl₃) and acetic acid/water or phosphorous acid (H₃PO₃) routes.

Main Reaction (using PCl₃ and acetic acid):

PCl₃ + 3CH₃COOH + H₂O

→