Selective toxicity of alkanolamines.

Area of Science:

• Microbiology
• Biochemistry
• Industrial Chemistry

Background:

• Alkaline environments can influence the efficacy of antimicrobial agents.
• Metalworking fluids require effective antimicrobial protection to prevent microbial contamination and degradation.
• Understanding the mechanism of antimicrobial action is crucial for developing targeted solutions.

Purpose of the Study:

• To investigate the antimicrobial effects of diethanolamine, dimethylamino-methyl-propanol, and butylethanolamine.
• To determine the influence of pH on the antimicrobial activity of these compounds.
• To elucidate the mechanism underlying their antimicrobial action and assess their suitability for metalworking fluids.

Main Methods:

• Assessing antimicrobial activity of diethanolamine, dimethylamino-methyl-propanol, and butylethanolamine across a range of pH conditions.
• Correlating antimicrobial efficacy with the proportion of uncharged forms of the compounds.
• Evaluating the potential for diffusion across cell membranes as a rate-limiting step.

Main Results:

• Antimicrobial effects of the studied compounds are significantly enhanced at high pH.
• A strong correlation exists between antimicrobial activity and the uncharged state of the molecules.
• Cell membrane diffusion is identified as the rate-limiting factor for antimicrobial action.

Conclusions:

• Diethanolamine, dimethylamino-methyl-propanol, and butylethanolamine exhibit enhanced antimicrobial properties in alkaline conditions.
• The mechanism of action involves diffusion of the uncharged forms through microbial cell membranes.
• These compounds are effective and appropriate antimicrobial agents for use in alkaline metalworking fluid formulations.