Why does THPS have an odor?

THPS stands for tetramethylolphosphine sulfate. Its specific gravity is approximately 1.4, and it is miscible with water in any proportion. At room temperature, its solubility is 300g/100ml of water. Our customers have reported a slightly pungent odor during use. Why does THPS have an odor? How is this odor generated? Is it harmful to humans or microorganisms? We will explain from several aspects below.

This product contains four hydroxymethyl groups. Hydroxymethyl groups are in dynamic equilibrium with formaldehyde in aqueous solution. Therefore, under normal circumstances, a small amount of formaldehyde will be present in THPS aqueous solution. In certain high-temperature environments, the volatilization and release of formaldehyde will increase. Additionally, if certain compound bactericides and water treatment agents are neutral or alkaline, the formaldehyde content in the environment will increase exponentially. Therefore, the odor is due to the small amount of formaldehyde in the product itself and the increased formaldehyde due to the alkaline environment during use.

Furthermore, since tetramethylolphosphine sulfate is an organic compound, it is a quaternary phosphorus salt. It naturally has a slight odor, which is not harmful to humans and is classified as a low-VOC product. Numerous European and American users, based on their stringent testing standards, have found that the odor is harmless to the environment.

However, it is important to note that a small number of our oilfield users have observed that, during the use of THPS, those with a stronger odor seem to have better slime-removing and bactericidal effects than those with a weaker odor. What is the reason for this? Currently, there is no unified explanation within the industry. We speculate that it may be due to a higher formaldehyde content in the stronger odor version, and formaldehyde itself is a bactericide. Could this indicate a synergistic bactericidal effect between tetramethylolpropionate (THPS) and formaldehyde during oilfield use? This viewpoint requires further verification.