Chem321:Acme processes

This summarizes the main processes operated at Acme.

(Note that these products are real compounds, and the processes are plausible, but they are fictitious.)

2-Thiopheneacetyl chloride (TAC)

Stage 1

Thiophene is heated with glycolide in the presence of an aqueous cerium chloride catalyst, to produce 2-thiopheneacetic acid (TAA). The TAA is extracted out of the water using the solvent ethyl acetate. It is purified by adding base, extracting out impurities, then adding acid to reform the 2-thiopheneacetic acid. The aqueous cerium chloride is recycled for the next batch, as is 80% of the ethyl acetate.

Stage 2

2-Thiopheneacetic acid is treated with thionyl chloride to produce TAC, which is then purified by distillation.

Hazards

• Thiophene is smelly and flammable, but not especially toxic.
• Ethyl acetate is flammable, but non-toxic.
• Glycolide and 2-thiopheneacetic acid may cause minor burns
• 2-Thiopheneacetyl chloride (TAC) and thionyl chloride are highly corrosive and will cause serious skin burns. They both react with moisture (thionyl chloride can react explosively) to produce corrosive acidic gases (hydrogen chloride and TAA or sulfur dioxide).

Waste

• 20% of the ethyl acetate, around 500 kg per day, is left containing extracted impurities from the TAA preparation. This is sent for incineration at Albany Incineration, Inc.
• Waste aqueous alkaline layers (comprising about 2.5 tonnes per day) are produced. These are neutralized with acetic acid, then sent out for disposal by Environmental Services, Inc.

2-Methylthiazoline

Cysteamine hydrochloride in toluene is treated with excess sodium hydroxide and toluene to produce a solution of cysteamine in toluene. The mixture is then treated with acetic anhydride to produce a solution of the product. After separation of the aqueous layer, the non-aqueous portion is then separated via fractional distillation to give pure 2-methylthiazoline and recovered toluene.

Hazards

• Cysteamine hydrochloride and cysteamine are mildly corrosive, and especially corrosive towards nickel and stainless steel.
• Sodium hydroxide is highly alkaline and corrosive
• Acetic anhydride is acidic and corrosive.
• 2-Methylthiazoline is flammable and smelly, but not especially toxic.

Waste

• Aqueous alkaline waste is neutralized with acetic acid to produce a solution of sodium acetate. This aqueous waste is then sent out for disposal by Environmental Services, Inc. (Around 3 tonnes per year)
• Distillation residues ("still bottoms") contain 2-methylthiazoline and tarry by-products. Flammable, smelly and toxic, this mixture is sent out for incineration by Albany Incineration, Inc.

More processes may be added in due course.