MGDA 3A 40: A Versatile Chelating Agent for Modern Industry

What is MGDA 3A 40?

MGDA 3A 40 refers to a 40% aqueous solution of Methylglycine N,N-diacetic acid (MGDA) in its trisodium salt form. Also known as Trisodium MGDA or Trisodium salt of methylglycine diacetic acid, it is a powerful, biodegradable chelating agent. MGDA is part of a new generation of environmentally friendly chelators, designed to replace older compounds like EDTA, NTA, and phosphates in various formulations.

The “3A” typically refers to methylglycine diacetic acid, where “3A” alludes to its three acetic acid groups, and “40” indicates a 40% concentration in water.

Chemical Properties

• Chemical formula (trisodium salt): C₇H₇NO₆Na₃

• Molar mass: ~271.1 g/mol (trisodium salt)

• Appearance: Clear to slightly yellow liquid (in solution form)

• Solubility: Fully water-soluble

• pH (of 40% solution): Typically 10–11

Applications of MGDA 3A 40

Due to its strong chelating power and excellent biodegradability, MGDA 3A 40 finds uses across various industries:

1. Detergents and Cleaners

• Used in automatic dishwashing detergents (ADW) and laundry detergents.

• Prevents scale and soap scum by binding calcium and magnesium ions.

• Enhances cleaning efficiency, especially in hard water.

2. Cosmetics and Personal Care

• Acts as a stabilizer and improves the performance of active ingredients.

• Common in shampoos, cleansers, and skin care products.

3. Industrial Cleaning

• Ideal for metal cleaning, bottle washing, and surface cleaning applications.

• Functions as a sequestering agent to improve the effectiveness of alkaline cleaners.

4. Water Treatment

• Used in boiler water, cooling towers, and reverse osmosis systems to control scaling and corrosion.

5. Textile and Paper Industry

• Serves as a complexing agent in bleaching, dyeing, and finishing processes.

6. Agriculture

• Helps chelate micronutrients (like iron, zinc, manganese), improving their bioavailability in fertilizers.

Benefits of MGDA 3A 40

• Eco-friendly: Rapidly biodegradable under OECD 301 guidelines (>60% in 28 days).

• Highly effective: Comparable or superior to EDTA and NTA in binding metal ions like Ca²⁺, Mg²⁺, Fe³⁺.

• Safe profile: Low toxicity and not classified as a carcinogen or mutagen.

• Stable across pH range: Works in both acidic and alkaline environments.

• Compatible with many formulations: Doesn’t interfere with surfactants or enzymes.

How is MGDA 3A 40 Made?

1. Starting Material: Methylglycine (also known as sarcosine): Sarcosine is a naturally occurring amino acid derivative.

2. Reaction with Chloroacetic Acid: Sarcosine is reacted with chloroacetic acid in the presence of a base. This step introduces the acetic acid groups needed for chelation.

3. Neutralization: The resulting acid form (MGDA) is neutralized with sodium hydroxide to form the trisodium salt.

4. Dilution: Finally, the trisodium MGDA is diluted with water to achieve a 40% concentration, creating the MGDA 3A 40 solution.

This process is designed to be clean and efficient, with a focus on minimizing byproducts and environmental impact.