PBTC | 2-Phosphonobutane-1,2,4,-tricarboxylic acid

2-Phosphonobutane-1,2,4,-tricarboxylic acid Or briefly PBTC is available in two powdery solid and liquid form, the liquid is being clear and pale yellow. In the below table you can see some of the chemical and physical properties of PBTC:

Chemical and physical properties:

Molecular Formula Molecular Weight Physical Description Density (20°C) g/cm3  Solubility
C7H11O9P 270.13 g/mol Dry Powder


1.27 to 1.30 Completely miscible with water

The most common use of  PBTC is to act as a scale inhibitor and corrosion inhibitor in water treatment. The water witch used in cooling systems or industrial applications generally has some impurities like calcium carbonate and metal ions. These impurities can cause a lot of problems, creating deposits in the pipes and paths, as well as causing corrosion in the equipment.

For example, in water cooling systems, water will move without interruptions in a cycle and it experiences different temperature and pressure conditions. The changes in temperature and pressure cause deposits of calcium and other ions to form, which can cause a lot of damage to the system.

Generally, scale control phosphonates are preferred to other materials, due to their excellent properties for dispersing metals and clay, as well as scale inhabitation.

AMP & HEDP have shown their high capabilities, but they also have two major problems: the limited solubility of their salts and their low resistance to oxidizing agents. PBTC is a very strong scale & corrosion inhibitor and is used in many industries. Due to its higher performance, it is very cost effective than standard phosphates such as HEDP/ATMP.

This material is required to control calcium carbonate and disperse iron and sludge. By blocking the reaction of metallic ions, phosphonates prevent them from reacting unwantedly and produce stable mixtures of water with multiple metal ions. PBTC can be used in environments with high hardness, high temperature, and high alkalinity.

In addition to the use of PBTC in the treatment of water, it can be used as fertilizer and pesticide in agriculture.

Applications of PBTC

Industrial water treatment / Cooling system waters

As previously mentioned, in systems which water plays a role as cooling fluid, or in boilers, the presence of substances such as calcium ions causes the formation of sediments inside the equipment, this can close the water path and cause fractures and many issues in the process. To solve this problem, the use of PTBC is common and effective.

PBTC in watre treatment

Industrial detergent

One of the most important uses of sulfonate compounds, such as PBTC, is the use of detergent production, the advantages of which include the following:

  • Reduce hardness and prevent ion deposition
  • Suspend the pollutants and prevent their re-sedimentation

Secondary oil recovery

In the process of oil extraction, oil is extracted from the well in the early stages by the pressure in its reservoir. But after a while, the pressure drops and they have to use some fluids to make enough pressure.

In offshore drilling, they use seawater to provide the required pressure. The water entering the well has high ion concentrations, which can be deposited after a while and cause clogging in the well, sediment inhibitors such as PBTC to prevent minerals such as calcium carbonate, calcium sulfate, barium sulfate, and strontium sulfate when drilling and in the production line, they are very efficient.

Some of the other applications of 2-Phosphonobutane-1,2,4,-tricarboxylic acid are: Antiseptics, Rust inhibitor in steel, As an inhibitor in concrete


  • This substance can cause serious eye problems.
  • In case of inhalation, it can cause respiratory irritation and coughing.
  • Causes skin irritation.
  • In case of swallowing, it will cause irritation and pain.