The synthesis of semipermeable membrane microcapsules using in situ cyanoacrylate ester polymerization.

A new material for the microencapsulation of biological systems was discovered and characterized with regards to the effects of reaction conditions on product yield. By using poly(cyanoacrylate ester), membrane microcapsules were produced with sufficient strength and porosity to be effective in a process environment for the immobilization and protection of encapsulated material. After synthesizing numerous monomeric cyanoacrylate esters, the n-butyl derivative was discovered to give the best results with regards to microcapsule formation. Microcapsules were prepared by a droplet technique in which an aqueous solution is sprayed into an organic solvent containing the cyanoacrylate ester monomer. By pre-treating the cyanoacrylate ester monomer with an anion exchange resin (Amberlyst A-21, Rohm and Haas, Philadelphia, USA), a significant reduction in the amount of acidic impurities which can adversely affect results was achieved. The use of polyvinylpyrrolidone as a polymerization initiator gave the best results of a variety of polymeric and non-polymeric initiators investigated. Successful encapsulations were achieved using a solvent mixture of 60% (v/v) iso-octane/40% trichloroethylene, 0.1% (w/v) polyvinylpyrrolidone initiator, pH 6.5 aqueous encapsulation solution, and 5% (v/v) methylcyanoacrylate/A-21 treated n-butylcyanoacrylate (added separately to solvent) made to a 4% (v/v) solution in solvent. Ester monomers were synthesized and used to prepare polymer membranes.

Multi-enzyme catalyzed rapid ethanol lowering in vitro.

Ethanol was oxidized to acetate by an enzyme system using yeast alcohol dehydrogenase (YADH), yeast aldehyde dehydrogenase (YALDH), and lactic dehydrogenase (LDH) recycling NAD in two model duodenal fluids and in canine duodenal aspirate in vitro. Sufficient enzyme activities were maintained to convert as much as 34% of the original ethanol to acetate with negligible acetaldehyde accumulation.

The dehydration of fermentative 2,3-butanediol into methyl ethyl ketone.

A solid acid catalyst consisted of sulfonic groups covalently bound to an inorganic matrice was developed to dehydrate 2,3-butanediol into methyl ethyl ketone. Rate constant and apparent activation energy of the dehydration reaction were determined. The decay course of the catalyst was a two-stage curve. The catalyst was deactivated more rapidly in the first stage than in the second stage. The strategy of maintaining constant degree of dehydration was employed to lengthen the lifetime of catalyst. Treatment of the 2,3-butanediol containing fermentation broth with activated carbon greatly facilitated the subsequent dehydration reaction.

Behaviors of southern red oak hemicelluloses and lignin in a mild sulfuric acid hydrolysis.

Removal and modification of southern red oak hemicelluloses and lignin in a 0.05%(w/v) sulfuric acid hydrolysis were investigated. The hydrolysis profile was to raise the reaction from room temperature to 150 degrees C for in 38 min and to extend the hydrolysis at 150 degrees C for 1 h. At the end of the hydrolysis, 25.5% of red oak components were dissolved, of which 58% was xylose and 17% lignin. As the hydrolysis proceeded from room temperature to 150 degrees C, a part of red oak xylan was removed to yield an oligomer fraction having maximal yield and average molecular weight of 3460 at 150 degrees C. This fraction and the bulk xylan extracted during the first 30 min at 150 degrees C were further degraded to give a lower molecular weight oligomer fraction, of which the yield and average molecular weight (2610) were highest at the end of the bulk removal of xylan. Red oak lignin, syringyl and guaiacyl units in particular, was increasingly removed with the progress of the hydrolysis. Lignin derivatives and a part of red oak extractives soluble in the hydrolysate were identified.

Modeling of percolation process in hemicellulose hydrolysis.

A mathematical model was developed for a percolation reactor in connection with consecutive first-order reactions. The model was designed to simulated acid-catalyzed cellulose or hemicellulose hydrolysis. The modeling process resulted in an analytically derived reactor equation, including mass-transfer effects, which was found to be useful in process desing and reactor optimization. The modedl was verified by experimental data obtained from hemicellulose hydrolysis.