The difference between Aluminum hypophosphite and aluminum diethyl hypophosphite

Aluminum hypophosphite and aluminum diethyl hypophosphite are two different organic phosphorus compounds, their differences are mainly reflected in the chemical structure, properties and applications. The following is a detailed comparison:

1. Chemical structure

Aluminum hypophosphite

-Chemical formula: Al (H₂PO₂)₃

-Structure: composed of aluminum ions (Al³⁺) and hypophosphite ions (H₂PO₂⁻), the phosphorus atom in hypophosphite is directly connected to two hydrogen atoms and one oxygen atom (P-H bond exists).

-Features: inorganic salt, no organic group.

Aluminium diethyl phosphate

-Chemical formula: Al[O₂P (CH₂CH₃)₂]₃

-Structure: the aluminum ion is combined with the diethyl hypophosphite, and the phosphorus atom connects two ethyl groups (-C₂H₅) and two oxygen atoms (P-C bond exists).

-Characteristics: organophosphorus compounds, containing ethyl organic groups.

2. Physical and chemical properties

3. Application

-Aluminum hypophosphite

-Flame retardant: used in plastics, rubber and other polymer materials, through decomposition to release phosphoric acid to promote carbon formation.

-Disadvantages: strong hygroscopicity, which may affect the performance of materials.

-Aluminum diethyl hypophosphite

-Efficient flame retardant: especially suitable for engineering plastics (such as PA, PBT), epoxy resin, etc., with both gas phase and condensed phase flame retardant mechanism.

-Advantages: good thermal stability, high compatibility with polymers, and low smoke and low toxicity.

4. Flame retardant mechanism difference

-Aluminum hypophosphite:

The heat absorption decomposition generates aluminum phosphate and phosphine (PH₃), which covers the surface of the substrate to isolate oxygen.

-Aluminum diethyl hypophosphite:

The aluminum phosphate carbon layer is decomposed and the ethyl free radical is released to capture the active free radicals in the combustion chain reaction (gas phase flame retardant).

5. Other distinctions

-Toxicity: Aluminum diethyl hypophosphite is usually less toxic and more environmentally friendly (such as halogen-free flame retardant trend).

-Cost: The synthesis process of aluminum diethyl hypophosphite is complex and the price is high.

Sum up

Both are phosphorus-based flame retardants, but aluminum diethyl hypophosphite is better in terms of heat resistance, compatibility and environmental protection due to the introduction of organic groups, suitable for high-end applications; aluminum hypophosphite is low cost and suitable for conventional flame retardant requirements. The choice should be based on material system and performance requirements.