Selection guide for pesticide intermediates:

1. Environmental friendliness

The general law of the relationship between biodegradability and its molecular structure is as follows: the hydrophobic base has a high linearity and is easy to degrade; the length of the hydrophobic chain has an impact on the degradability; the ethoxy chain is short and easy to degrade; Benzene sulfonate is easily degraded. For anionic emulsifiers, alkyl sulfates (AS) Z are easily degradable. Linear alkyl benzene sulfonate (LAS) chain length is easily degradable in C6-C12Z. Alkyl chains are branched and the closer they are to the main chain, the more difficult it is to degrade. For non-ionic emulsifiers, short-chain alkyl groups, straight-chain alkyl groups, no phenolic groups in the molecule, less PO and EO units are easy to degrade, and EO chains of the same length are easier to degrade than PO chains.

2. Security

The toxicity of anionic emulsifiers is relatively low, for AS, the carbon number less than 8 or more than 14 is less toxic than its homologues. Most non-ionic emulsifiers have lower toxicity than anionic ones. The lowest ones are polyethylene glycols (PEG), followed by sugar esters, fatty alcohol polyoxyethylene ethers (AEO) and sorbitan fats. Acid esters and their adducts with ethylene oxide (Span, Tween). For EO type nonionic emulsifiers, generally ester type (Tween of sorbitan polyoxyethylene compound) is less toxic than ether type (AEO and alkylphenol polyoxyethylene ether APEO). Polyol types such as sorbitan esters, glycerides, etc. are expected to be substantially nontoxic.

3. Mildness

The order of skin irritation of some anionic emulsifiers: ABS ( L AS ) > AS > AOS (α-alkenyl sulfonate) > AES (fatty alcohol polyoxyethylene ether sulfate). Comparing the skin irritation intensity of AS, LAS and AOS with different chain lengths, in general, the emulsifier of C10-14 is more irritating to the skin, and the chain length of C12 is the most irritating. Tween in EO type nonionic emulsifier is less irritating than AEO; the homologues of various EO type emulsifiers are less irritating as the number of added ethylene oxide increases. The introduction of polyethylene glycol (PEG) groups into the molecule can greatly reduce the irritation of the emulsifier.