ART
BEAUTY & WELLNESS
CRAFT
CULTURE & HISTORY
ENTERTAINMENT
ENVIRONMENT
FOOD & DRINKS
REVERSE ENGINEERING
SCIENCES
SPORTS
TECHNOLOGY
WEARABLES
Terephthalic Acid: Para-Xylene Oxidised by Air with Manganese and Bromide
Terephthalic acid is the acid half of PET. Both methyl groups of para-xylene are burnt to acid groups by air under pressure in hot acetic acid, with a little manganese salt and bromide as catalyst: the Mid-Century process of Saffer and Barker (US 2,833,816, 1958). The acid does not dissolve, so it is simply filtered off. Example 24 of the patent, all parts by weight.
The picture: our diagram of the reactor.
Advanced
1 day
Instructions
1
1
Charge the reactor
Charge the reactor
Into a corrosion-resistant pressure reactor with a water-cooled condenser on top, put 75 parts para-xylene, 150 parts acetic acid, 1 part manganese acetate (tetrahydrate) and 0.75 part ammonium bromide.
Materials for this step:
Para-Xylene75 partsTools needed:
Acetic Acid (Glacial)
Manganese Acetate
Ammonium Bromide
Balance Scale
Pressure Reactor
Condenser Coil
Chemical Splash Goggles
Chemical-Resistant Gloves2
2
Pressurise with air and heat to 385 °F
Pressurise with air and heat to 385 °F
Raise the pressure to 400 psig with air, blown in near the bottom. Set the vent so gas leaves at 3,000 volumes per hour per volume of liquid. Heat to 385 °F (196 °C), then switch the heat off: the reaction heats itself.
Tools needed:
Pressure Reactor
Industrial Air CompressorCondenser Coil
Thermometer - Lab3
3
Hold at 385–400 °F
Hold at 385–400 °F
Once the first rush is over, heat as needed to hold 385–400 °F (196–204 °C), 1.5 hours in all. It is finished when the exit gas is back to 20–21 % oxygen (Orsat analysis).
Tools needed:
Pressure ReactorThermometer - Lab
Orsat Gas Analyser4
4
Cool, empty and filter
Cool, empty and filter
Cool to 185 °F (85 °C) and let the pressure off. Push the liquid out at 150–200 °F with nitrogen pressure, scrape out the solid, and filter everything together.
Tools needed:
Nitrogen Gas Cylinder
Glass Funnel - Stemmed
Filter PaperChemical-Resistant Gloves5
5
Wash and dry
Wash and dry
Wash the terephthalic acid twice with hot acetic acid (75 ml each in the example) and dry it. The patent got 115 parts by weight from 100 of para-xylene.
Tools needed:
Acetic Acid (Glacial)Glass Funnel - StemmedFilter Paper
Drying OvenMaterials
1- 75 partsPlaceholder
Tools Required
15- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
This blueprint makes
Related Blueprints
These blueprints share knowledge with this one — techniques, materials, or principles that connect them in the learning graph.
CC0 Public Domain
This blueprint is released under CC0. You are free to copy, modify, distribute, and use this work for any purpose, without asking permission.
Support the Maker by purchasing products through their Blueprint where they earn a Maker Commission set by Vendors, or create a new iteration of this Blueprint and include it as a connection in your own Blueprint to share revenue.