We report a means for efficient and selective extraction of carbon dioxide (CO(2)) at low to medium concentration from mixed gas streams. CO(2) capture was accomplished by use of a novel enzyme-based, facilitated transport contained liquid membrane (EBCLM) reactor. The parametric studies we report explore both structural and operational parameters of this design. The structural parameters include carbonic anhydrase (CA) concentration, buffer concentration and pH, and liquid membrane thickness. The operational parameters are temperature, humidity of the inlet gas stream, and CO(2) concentration in the feed stream. The data show that this system effectively captures CO(2) over the range 400 ppm to at least 100,000 ppm, at or around ambient temperature and pressure. In a single pass across this homogeneous catalyst design, given a feed of 0.1% CO(2), the selectivity of CO(2) versus N(2) is 1,090 : 1 and CO(2) versus O(2) is 790 :1. CO(2) permeance is 4.71 x 10(-8) molm(-2) Pa(-1) sec(-1). The CLM design results in a system that is very stable even in the presence of dry feed and sweep gases.

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The low resolution mass spectra of 5,6‐monoepoxyretinoic acid, 5,8‐monoepoxyretinoic acid, 5,6‐monoepoxyretinyl acetate, 5,8‐monoepoxyretinyl acetate, 5,8‐monoepoxyretinal, trimethylsilyl‐5,6‐monoepoxyretinoate, trimethylsilyl‐5,8‐monoepoxyretinoate, methyl‐5,6‐monoepoxyretinoate, methyl‐5,8‐monoepoxyretinoate, β‐C19‐retinal and β‐C19‐retinyl acetate‐analogs of vitamin A—are presented. Characteristic features of the spectra are discussed. In addition, high resolution mass measurements are presented for six fragment ions of all‐trans‐retinoic acid and eleven fragment ions of methyl‐5,6‐monoepoxyretinoate.

Benzoylferrocene steroid but was clearly neither 5anor 5/3-cholestane.24 The infrared spectrum indicated the absence of any functional groups such as OH or carbonyl. The molecular weight of the material was 372 by mass spectrometry.Reduction of cis,cis,irans-Perhydro-9b-phenalenol (15) by Hydride Transfer.-Alcohol 15 (1.94 g, 10 mmol) was dissolved in 40 ml of methylene-chloride along with 2.99 g (11.5 mmol) of triphenylsilane and 7.3 ml (11.2 mg, 100 mmol) of trifluoroacetic acid. After 48 hr the solution was poured in 250 ml of saturated sodium bicarbonate, the layers separated, and the aqueous layer was extracted with 50 ml of methylene chloride. The combined organic extracts were washed with 50 ml of saturated sodium bicarbonate, dried over magnesium sulfate, concentrated, and chromatographed on 40 g of silica gel (Woelm). Elution with 120 ml of pentane yielded 1.63 g (92%) of 18. The reaction product was identical with respect to ir, nmr, and retention time