PBTC 50 (Phosphonobutane Tricarboxylic Acid 50%) 2019-09-11T05:47:52+00:00

Project Description


PBTC; Dequest 7000; Mayoquest 2100; Bayhibit AM; Belclene 650; Codex 551; Briquest PBTC, PBTC tricarboxylic acid, 2-phosphonobutane-1 2 4-tricarboxylic acid

CAS No.:

37971-36-1, from ChemIDplus, EPA Chemicals under the TSCA, EPA DSStox, European Chemicals Agency (ECHA).

40372-66-5, from ChemIDplus, European Chemicals Agency (ECHA).

EC No.:

253-733-5, from European Chemicals Agency (ECHA).

254-894-4, from European Chemicals Agency (ECHA).

Molecular Formula:


Molecular Weight:


Structural Formula:

phosphonobutane tricarboxylic acid


Phosphonobutane tricarboxylic acid is excellent as both antiscalants and corrosion inhibitors, because of its structural feature of carboxylic acid and phosphoric acid. The PBTCA chemical is stable and high efficiency in the condition of high hardness, temperature, pH value, and indexed matter concentration.

While usually building with other organophosphates, PBTCA acid also widely works together with zinc salts whose solubility it will increase.  Phosphonobutane tricarboxylic acid can improve zinc salt solubility. PBTC also have a higher tolerance to oxidation agents like chlorine or bromine in the system.

The first reaction for PBTC 50 production is between dialkyl phosphite (usually dimethyl phosphate in China) and maleic acid dimethyl ester under basic catalyst. Tetraalkyl ester of phosphonosuccinic acid forms and immediately reacted with methyl acrylate. The following thereupon saponification yields PBTCA.


AppearanceColorless or light yellow transparent liquid
Active acid %49.0 – 51.0
Phosphorous acid (as PO33-)%0.8 max
Phosphoric acid (as PO43-)%0.5 max
pH (1% water solution)1.5 – 2.0
Fe ppm20.0 max
Chloride ppm10.0 max
Density (20℃) g/cm31.27 min


As an excellent inhibitor to both scale and corrosion, PBTC 50 is the excellent stabilizer for zinc salt. It is widely applied in the refilling system and circulated cooling system for oil fields, steel mills, and mines. PBTC 50 can be used in situations of high temperature, high hardness, high alkali, and high concentration index. Besides, PBTC is used to chelate metal ions in lavation and detergent industries as metal detergent. In pH 7-10, 5-15 mg/L is recommended if only PBTC.

PBTC 50 is usually used together with the zinc salt, copolymer, organophosphine, imidazole, and other water treatment agents. When used alone, the dosage of 5-15 mg/l is preferred.

Package and Storage:

200L plastic drum, IBC (1000L), customers’ requirement.

Storage for one year in a shady room and dry place.

Safety Protection:

Acidity, Avoid contact with eye and skin, once contacted, flush with water.

Transport Info:

Corrosive. IMO class 8, UN 3265.