Hexabromobenzene
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Large scale plastic waste PBT plastic hydrolysis experiment
PBT plastic, used in electronic equipment contains about 30% glass fibre 10% brominated flame retradant and 60% PBT polymer. Brominated flame
retradant usually TBBA oligomers.
About 19 kg spent PBT plastic from electronic wastes used in this experiment. Experiment carried out in 2 part plastic about 10 kg each for use all
sodium hydroxide. Plastic was crashed with pliers.
About 3.8 kg very old(30 year) sodium hydroxide and 300 gr potassium hydroxide used for hydrolysis experiment. Alkali dissolved in 20 liters water
and 900ml ethanol was added(ethanol accelerates reaction in several times). Hydrolysis solution and 10 kg crushed plastic was added in 50l vessel
After 3 month solution was very alkaline and many sodium hydroxide remained in solution. For this reason solution was merged from solid plastic.
Plastic after 3 month hydrolysis became very soft and crushed into powder. It was mainly glassfibre and fillers. Polymer and flame retradant was
dissolved in alkaline solution
Remained solution was again placed in vessel with 10 kg plastic. Also old plastic was washed with water for extract hydrolysis remains solution and
extract was united with hydrolysis solution.
After other 5 month solution was merged from plastic and plastic was washed with water.
Hydrolysis solution after reaction was filtrated evaporated in 100 liter vessel 2000 sq sm area at open air under temperature about 22C. Summary
evaporation time 5 month
At first disodium terephtalate crystalizes as scale calcite like mass. After this crystalizes other compoud as orange crystals. It possible brominated
flame retradant. After this solution became very viscous and nothing crystalizes and brown liquid remains . It mainly very crude 1,4 butanediol with
impurties and up to 10% water. Salts is not soluble in butanediol
Summary recived about 4.8-5 kg disodium terephtalate about 2.5 liter crude BDO and 500 gr some brown crystals unknown salt possible TBBA sodium salt.
Sodium terephtalate may be used to prepare terephtalic acid, benzene and possible may be reduced to p-methylhyroxy benzoic acid
Butanediol may be converted to THF, succinic acid and hydroxy butyric acid
TBBA can be heated with lime or soda to prepare bromide for bromine syntesys.
If you want accelerate hydrolysis and evaporation you can heat solution to 50c. Hydrolysis and evaporation will take a couple of weeks not month
Slow evaporation hepls grows large crystals which easy can be separated from solution
With similar method polyamide 66 plastic from automobile can be hydrolysed. It marked as PA66 GF33(glassfibre 33%). For hydrolysis polyamides acids
such as hydrochloric and sulfuric must be used. Adipic acid and hexamethelenediamine may be prepared.
Many chemical can be obtained from plastic and other wastes.
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Boffis
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@ Hexabromobenzene; these were interesting experiments! I have carried out a fair amount of work on PET hydrolysis but I have never heard of PBT
(polybutylene terephthalate.) before reading your post. What sort of electrical bits are we talking about? The polymer sheets they make PCB out of or
the sort of plastic they make the interior of sockets and circuit breakers out of? Incidentally what does TBBA stand for?
By the way sodium terephthalate is practically insoluble in strong sodium hydroxide and carbonate solutions so as evaporation occurs the sodium
terephthalate starts to crystallise rather suddenly.
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Hexabromobenzene
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These were in the basis of the body from the spent compact flouriscent lamps, the body of computer fans, you can also use connectors from the
motherboards and PBT also uses in electric irons
TBBA- Tetra bromo bisphenol A
For extraction all sodium terephtalate large excess of water was used. Evaporation carried out without heating. After hydrolysis solution does not
content sodium hydroxide. It was excess plastic
[Edited on 23-2-2023 by Hexabromobenzene]
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