Generally, the choline chloride(CC) is produced from Trimethylamine as raw material. In China, the trimethylamine is produced in choline chloride plants, huge quantity is used on the CC from upstream line in inner plant.
But except China, many plants who plan to set up choline chloride line have no trimethylamine, this is big block for the project. How to solve it?
Because the trimethylamine digests with HCL to generate the trimethylamine hydrochloride(TMAC), users can import TMAC from us(KNMM) directly to produce choline chloride.
The following is the detailed process for the production of choline chloride using (TMAC), analyzed step by step:
### ** Process Flow Overview * *
The chemical formula of choline chloride:
* * [(CH ₃) ₃NCH₂CH₂OH] Cl * *
Its core is to form choline by trimethylamine reaction with ethylene oxide, and then combined with hydrochloric acid to form salt. If the raw material is * * trimethylamine hydrochloride ((CH ₃) ₃ NHCl) * *, trimethylamine should be released first and then react with ethylene oxide. The specific steps are described as follows:
** Production step * *
1. * * Dissociation of trimethylamine hydrochloride * *
- ** Reaction conditions * *: dissolve trimethylamine hydrochloride in water and add * * sodium hydroxide (NaOH) * * to neutralize hydrochloric acid to release free trimethylamine:
{(CH₃)₃NH⁺Cl⁻ + NaOH → (CH₃)₃N + NaCl + H₂O}
- ** Operating points * *:
-Control the pH to 10-12 to ensure full release of trimethylamine.
-Recovery free trimethylamine gas by distillation or gas absorption (note explosion-proof measures).
2. * * Addition reaction of trimethylamine and ethylene oxide * *
- ** Reaction type * *:
{(CH₃)₃N + CH₂CH₂O → (CH₃)₃N⁺CH₂CH₂O⁻}
- ** Conditions * *:
- ** Temperature * *: 40~60℃ (ethylene oxide is explosive, the temperature should be strictly controlled).
- ** Pressure * *: atmospheric pressure or micro-negative pressure (to avoid ethylene oxide leakage).
- ** Mar ratio * *: trimethylamine and ethylene oxide are fed 1:1 accurately to prevent excess ethylene oxide residue.
3. * * Hydrochloric acid neutralizes salt formation * *
-Neutralizes the choline intermediate generated by the reaction with * * hydrochloric acid (HCl) * * to generate choline chloride:
{(CH₃)₃N⁺CH₂CH₂O⁻ + HCl → [(CH₃)₃NCH₂CH₂OH]⁺Cl⁻}
- ** Operating points * *:
-Control the pH value to 6 to 7 to ensure full neutralization.
-Reheat heat, cooling and maintain temperature below 50℃.
4. * * Concentration and crystallization * *
- ** Concentration * *: Remove water by vacuum evaporation to increase the solution concentration.
- ** Crystallization * *: cool to 20~30 crystals of choline chloride ℃.
- ** Centrifugation * *: separate the crystal and the mother liquid by centrifuge, the mother liquid can be recycled.
5. * * Drying and Packaging * *
- ** Dry * *: The fluidized bed dryer dries the crystal at 60~80℃ to 1% water content.
- ** Sieve * *: Get uniform particles through screening.
- ** Packaging * *: sealed and moisture-proof, to avoid moisture-absorbing agglomeration.
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** Key control point * *
1. * * Safety control * *:
-Ethylene oxide is flammable and explosive, requiring inert gas (such as nitrogen) protection and anti-static equipment.
-The trimethylamine gas is toxic and requires closed operation and exhaust gas absorption system (such as pickling tower).
2. * * Purity control * *:
-Test for free trimethylamine residue (0.1% required).
-Control the complete reaction of ethylene oxide to avoid byproducts (e. g., polyethylene glycol).
3. * * Energy consumption optimization * *:
-Using multieffect evaporation
