**Aldicarb (also called 2,2-dichloro-1,3-bis(4‑tert‑butylphenyl)imidazolidin-4‑one)** is a carbamate insecticide that was introduced in the early 1990s and has been used mainly on tropical crops such as sweet potatoes, cassava, and certain fruits. Below is a concise, practical guide covering its mechanism of action, safety profile, handling procedures, and recommended personal protective equipment (PPE).
| **Section** | **Key Points** | |-------------|----------------| | **1. Mechanism of Action** | • Inhibits acetylcholinesterase (AChE) in insects. • Carbamate group binds reversibly to the serine residue at AChE active site, preventing breakdown of acetylcholine. • Leads to accumulation of acetylcholine → overstimulation of cholinergic receptors → paralysis and death. | | **2. Safety Profile** | • Classified as a moderately hazardous pesticide (OECD 4). • Toxicity: - Oral LD₅₀ in rodents ~30–70 mg/kg. - Dermal exposure can cause irritation, systemic absorption possible. - Inhalation of dust may irritate respiratory tract. - **Precautions**: avoid ingestion/eye contact; wash hands after handling. | | **3. Handling & Storage** | • Store in tightly sealed container, away from heat, light, and incompatible substances (acids, oxidizers). • Keep out of reach of children and pets. • Use only in well‑ventilated areas or under fume hood. | | **4. First‑Aid Measures** | • **Skin contact**: Wash with soap & water; seek medical attention if irritation persists. • **Eye contact**: Flush eyes with water for at least 15 min, then seek care. • **Ingestion or inhalation**: Do not induce vomiting; call poison control. | | **5. Disposal** | • Contact local environmental agency for guidance on hazardous waste disposal. • Do not pour down the drain or onto the ground. |
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## 3. Summary of Key Points
| Item | Recommendation | |------|----------------| | **Use of 2‑Methyl-1‑propanol (tert‑butyl alcohol)** | • Can be used in place of isopropanol for esterification, but will give a different product; not ideal for standard methyl acetate synthesis. • If you must use it, adjust the stoichiometry: 2 mol of tert‑butyl alcohol per 1 mol of acetic acid to form methyl 2‑methylpropanoate (tert‑butyl ester). | | **Esterification with Acetyl Chloride** | • Reaction is faster and more efficient than using acetic acid. • Requires careful handling due to corrosive, lachrymatory properties. • Follow the safety protocol: PPE, fume hood, emergency eyewash. | | **Safety Precautions** | • Wear goggles, gloves, lab coat; avoid skin contact with acetyl chloride. • Keep away from moisture; store in sealed containers under dry conditions. • Use a fume hood; have an eyewash station and fire extinguisher nearby. |
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## 7. Summary Table
| **Reaction** | **Reactants** | **Conditions** | **Product (Yield)** | **Notes** | |--------------|---------------|-----------------|---------------------|-----------| | **A** | 1‑Butanol + Acetyl chloride | Dry conditions, 0–25 °C | Butyl acetate (~70–80 %) | Requires anhydrous environment; can be performed in a sealed tube or Schlenk line. | | **B** | 1‑Butanol + Acetyl chloride (excess) | Dry conditions, 0–25 °C | Diacetylbutane (~60–70 %) | Higher stoichiometry needed; product may decompose if heated excessively. |
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### Practical Notes
- Perform the reactions in a sealed tube or under nitrogen to avoid moisture. - Use freshly distilled acetyl chloride or anhydrous conditions to maximize yield. - If you wish to isolate the diacetyl butane (reaction B) selectively, use a higher stoichiometric ratio of acetyl chloride and keep the temperature below 25 °C. - Monitor reaction progress by thin‑layer chromatography (TLC) or gas chromatography (GC).
Feel free to adjust quantities depending on the scale you need. Happy experimenting!
