What are the chemical components of PCA?

PCA (Phosphonocarboxylic Acid or Phosphino Carboxylic Acid) is a class of hybrid water treatment chemicals that combine phosphonic acid (–PO₃H₂) and carboxylic acid (–COOH) functional groups in a single molecule. The exact chemical components depend on the specific type of PCA, but here’s a breakdown of the most common variants:

1. Common PCA Types & Their Chemical Structures

(1) PBTCA (2-Phosphonobutane-1,2,4-Tricarboxylic Acid)

Chemical Formula: C₇H₁₁O₉P

Structure:

HOOC-CH₂-C-CH₂-COOH

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PO₃H₂

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CH₂-COOH

Key Components:

1 phosphonate group (–PO₃H₂) for h3 metal ion chelation.

3 carboxylate groups (–COOH) for dispersing suspended particles.

(2) HPA (Hydroxyphosphonoacetic Acid)

Chemical Formula: C₂H₅O₆P

Structure:

HOOC-CH(OH)-P