3031-15-0

Poly(3-hydroxybutyrate) or PHB is an energy storage material of microbial organisms and can be reformed into hydrocarbon oils rich with aromatic compounds. This work investigated the main reaction routes from PHB to the key intermediates and final hydrocarbons. The main sequential reactions under catalysis of phosphoric acid at moderate temperatures (200-230 °C) consist of: (1) decomposition of PHB into crotonic acid, a major monomeric intermediate, (2) deoxygenation of crotonic acid, and (3) combination of the deoxygenated molecules. The oxygen in PHB is removed as CO2 and H2O in stage (2), involving decarboxylation and ketonization of crotonic acid. The main aromatic compounds are formed in stage (3) from propylene and 2,3-dimethyl-2-cyclopenten-1-one as two key intermediates, the former from decarboxylation and the latter from ketonization of crotonic acid. The reaction routes reveal that the formation of aromatics is affected to a great extent by the concentrations of phosphoric acid and water in the reaction, which can be used to control the composition of hydrocarbon oil.

Cycloreversion of arene endoperoxides 1-4 can be induced by photoexcitation of their electron donor-acceptor complexes with tetracyanoethylene.

The title compound (2) was prepared by condensing a bis(silole) 1 with benzyne.Thermolysis of 2 in the presence of anthracene, 9,10-dimethylanthracene (DMA), 2,3-dimethylbutadiene, and two acetylenes is described in detail.X-ray structures for the anthrac

Chloromethyl derivatives synthesized by the chloromethylation of naphthalene and methylnaphthalenes were converted into the corresponding triphenylphosphonium salts.Alkaline hydrolysis of the latter gave 1-methylnaphthalene and some di-, tri-, and tetramethylnaphthalenes. 9-Methylphenanthrene was obtained similarly from phenanthrene.The corresponding diarylethenes were synthesized from the phosphonium salts by the Wittig reaction.

Synthesis as well as the thermal and photochemical behaviour of compounds with ring skeletons 1 and 3 are described.Whereas the former are accessible by standard procedures the approach to the bicyclobutane derivatives is based on the isomerization of diester 1b into valence isomer 3b which can be achieved in good yield by SiO2 or Al2O3.There are only minor differences in the cleavage of the pairs 1/3 provoked by heating or photochemical excitation.This is even true for irradiations in argon at 10 K.Under those conditions anhydrides 1a and 3a form the samecharge transfer complex 28a between tetramethylcyclobutadiene and phthalic anhydride.A direct detection of tetramethyltetrahedrane using these means is not possible.