Amine-Based pH Regulation for Metalworking Fluids: A Monoethanolamine (CAS 141-43-5) Approach

Monoethanolamine (CAS No. 141-43-5), with the molecular formula C2H7NO, is a compound belonging to the class of aliphatic alcohol amines. At room temperature, it appears as a colorless, viscous liquid that is miscible with water and most organic solvents, such as ethanol. Chemically stable, it exhibits alkalinity, emulsifying properties, and reactivity. As a core raw material in the metalworking fluid and cutting fluid sector, it is widely utilized across various global industries, offering targeted solutions to formulation challenges in fields like mechanical manufacturing and fine chemicals.

In the development of metalworking and cutting fluids, the primary objectives are achieving corrosion inhibition, lubrication, and pH stability to ensure processing efficiency and product quality. Traditional formulations often rely on blends of conventional amines and ester additives. The advantage of these approaches lies in the ready availability of raw materials and lower costs, enabling basic anticorrosion and lubricating functions suitable for low-end product development. However, they present notable drawbacks: limited anticorrosion efficacy, susceptibility to microbial contamination leading to system degradation; inconsistent lubricity that fails to balance cooling and protection needs; pH fluctuations that compromise stability; and poor compatibility with other components, often resulting in stratification or functional failure.

Monoethanolamine addresses these challenges effectively. Its inherent alkalinity allows for precise pH adjustment, maintaining system stability and inhibiting microbial growth to prevent fluid deterioration. The synergistic action of its hydroxyl and amino groups facilitates the formation of stable emulsions with lubricating components, enhancing lubricity, reducing friction between metal parts and tools, and aiding in heat dissipation to ensure machining precision. Furthermore, it demonstrates excellent compatibility with surfactants, rust inhibitors, and other additives, preventing phase separation and extending the product's service life.

Beyond its critical role in metalworking and cutting fluids, monoethanolamine serves as an intermediate in the synthesis of surfactants for applications in daily chemicals and textile auxiliaries. It is also employed as a gas purifying agent to remove acidic impurities from industrial gases and as a pH adjuster in cosmetics, pharmaceuticals, and food processing. This multifunctionality underpins its widespread application across global industrial systems.

As global industries increasingly prioritize precision and regulatory compliance, demand for monoethanolamine remains consistently robust due to its stable performance and strong adaptability. Potential challenges include the need for precise dosage control to prevent equipment corrosion due to its strong alkalinity and, in some advanced applications, the necessity to compound it with other alcohol amines, which adds complexity to formulation development. Looking ahead, ongoing process advancements are expected to further enhance its compatibility, solidifying its core position in metal processing and related industrial fields.

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