Polymerization ferf-butylcatechol

Butadiene is stored in a cool and well-ventilated location separated from combustible and oxidizing substances. Small amounts of stabilizers, such as o-dihydr-oxybenzene, j)-ferf-butylcatechol, or aliphatic mercaptans, are added to prevent its polymerization or peroxides formation. The cylinders are stored vertically and protected against physical damage. 

Synonyms PTBC 4-ferf-butylcatechol 4-tert-butylpyrocatechol TBC 4-(i,i-dimethylethyl)-i,2-benzenediol tertiary-butylcatechol Uses antioxidant in polyester resins polymerization inhibitor in PVC antioxidant in oil A... 

Ziegler-Natta solution polymerization processes are very sensitive to impurities. Both the monomer and solvent streams must be well purified. Carbonyl and acetylenic impurities, common in crude monomer streams, must be removed along with the common polymerization inhibitor ferf-butylcatechol. Molecular weight control is often accomplished by the addition of chain-transfer agents in certain Ziegler-Natta systems. 

The use of phenols such as ferf-butylcatechol as free-radical scavengers is based on the fact that phenolic hydrogens are readily abstracted by radicals, producing relatively stable phenoxyl radicals that interrupt chain processes of oxidation and polymerization. Alcohols such as cyclohexanol, on the other hand, do not function as radical scavengers. Explain why the two types of molecules differ in their abilities to donate a hydrogen atom to a radical, R. ... 

SCHEME 24.8 Polymerization of epoxides with ZnEt2/l-phenoxy-2-propanol/4-ferf-butylcatechol. 

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