摘要:
Method for quantitatively analyzing substances containing elements other than carbon, hydrogen and oxygen by (1) adsorbing such substances on a particulate, substantially dust and contaminant free carbonized product prepared by (A) first partially dehydrochlorinating a normally crystalline vinylidene chloride polymer at temperatures below the melting point of such polymer to an extent of at least about 5 percent of theoretical HCl loss, then (B) completing the dehydrochlorination of such material, in the substantial absence of oxygen, by heating the material to carbonizing temperatures of from about 600.degree.C to about 1200.degree.C; then (2) analyzing the substance adsorbed on such carbonized product.
摘要:
An improved process for the hydration of acrylonitrile to acrylamide where nitrile and water are contacted with a heterogeneous hydration catalyst and the process is improved by utilizing as feed acrylonitrile and water which are substantially free of oxazole. Acrylamide monomer of enhanced stability against premature polymerization is obtained.
摘要:
An on-line multidimensional system which includes a liquid chromatograph having an on-line connection to a pyrolysis probe, which in turn has on-line connection to a gas chromatograph. Preferred applications use a size-exclusion chromatograph coupled to a pyrolysis probe coupled to a gas chromatograph to simultaneously produce composition as a function of molecular weight/size information for polymeric materials.
摘要:
A fiber-optic probe, useful for light scattering and luminescence measurements, which comprises at least one optical fiber for transmitting light into a sample and at least two optical fibers for collecting light from the sample. The probe may further comprise a shield surrounding the fibers and having an optical window at one end to protect the fibers from hostile environments. When used in conjunction with a laser as a light source, the probe is particularly suited for Raman spectroscopy.
摘要:
An on-line multidimensional system which includes a liquid chromatograph having an on-line connection to a pyrolysis probe, which in turn has on-line connection to a gas chromatograph. Preferred applications use a size-exclusion chromatograph coupled to a pyrolysis probe coupled to a gas chromatograph to simultaneously produce composition as a function of molecular weight/size information for polymeric materials.
摘要:
Packing tube membranes or membrane channels for Ion Chromatography with inert or charged ion exchange beads greatly increases overall suppressor efficiency. The length of membrane required is reduced, e.g. from 20 feet to 5 feet and bandspreading is reduced from 870 .mu.l to 200 .mu.l. This significant increase in efficiency is attributed to the mixing action of the packing on the flow stream which results in convective radial transport much more rapid than the diffusion controlled transport observed in unpacked membranes. The technique is also described for developing more efficient liquid chromatographic post-column reactors for adding reagent to the column effluent to increase detection sensitivity.