Aldol condensation of the inferior aldehydes over dealuminated clinoptilolite

The catalytic performances of dealuminated clinoptilolite in the vapour-phase condensation of acetaldehyde and formaldehyde were investigated. The activity of dealuminated clinoptilolite in terms of the overall conversion of the acetaldehyde is comparable with that of the cation-exchanged forms (Na+, Ni2+, Fe3+). The dealumination process of clinoptilolite exhibits a favourable effect on the catalytic selectivity toward crotonaldehyde formation.

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The construction of a series of hierarchical MWW-type zeolites and their catalytic performances for bulky aldol condensation

Microporous and Mesoporous Materials ◽

10.1016/j.micromeso.2018.04.017 ◽

2018 ◽

Vol 268 ◽

pp. 117-124 ◽

Cited By ~ 2

Author(s):

Xin Du ◽

Yanquan Yang ◽

Dier Shi ◽

Cong Lin ◽

Yaming Qiu ◽

...

Keyword(s):

Aldol Condensation ◽

Catalytic Performances

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Characterization of Chemical Impurities in Glutaraldehyde

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100116723 ◽

1975 ◽

Vol 33 ◽

pp. 620-621

Author(s):

B. J. Grenon ◽

A. J. Tousimis

Keyword(s):

Glutaric Acid ◽

Spectroscopic Analysis ◽

Aldol Condensation ◽

Condensation Product ◽

Amorphous Solid ◽

Water Soluble ◽

Impurity Component ◽

Chemical Impurities ◽

Soluble Liquid

Ever since the introduction of glutaraldehyde as a fixative in electron microscopy of biological specimens, the identification of impurities and consequently their effects on biologic ultrastructure have been under investigation. Several reports postulate that the impurities of glutaraldehyde, used as a fixative, are glutaric acid, glutaraldehyde polymer, acrolein and glutaraldoxime.Analysis of commercially available biological or technical grade glutaraldehyde revealed two major impurity components, none of which has been reported. The first compound is a colorless, water-soluble liquid with a boiling point of 42°C at 16 mm. Utilizing Nuclear Magnetic Resonance (NMR) spectroscopic analysis, this compound has been identified to be — dihydro-2-ethoxy 2H-pyran. This impurity component of the glutaraldehyde biological or technical grades has an UV absorption peak at 235nm. The second compound is a white amorphous solid which is insoluble in water and has a melting point of 80-82°C. Initial chemical analysis indicates that this compound is an aldol condensation product(s) of glutaraldehyde.

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Characterization of GaAs/AlGaAs quantum wells and quantum wires by chemical lattice imaging

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100171419 ◽

1994 ◽

Vol 52 ◽

pp. 736-737

Author(s):

A. Carlsson ◽

J.-O. Malm ◽

A. Gustafsson

Keyword(s):

Quantum Well ◽

Quantum Wells ◽

Quantum Wires ◽

Vapour Phase ◽

Quantitative Information ◽

Lattice Imaging ◽

Vapour Phase Epitaxy ◽

Metalorganic Vapour Phase Epitaxy ◽

High Resolution Images

In this study a quantum well/quantum wire (QW/QWR) structure grown on a grating of V-grooves has been characterized by a technique related to chemical lattice imaging. This technique makes it possible to extract quantitative information from high resolution images.The QW/QWR structure was grown on a GaAs substrate patterned with a grating of V-grooves. The growth rate was approximately three monolayers per second without growth interruption at the interfaces. On this substrate a barrier of nominally Al0.35 Ga0.65 As was deposited to a thickness of approximately 300 nm using metalorganic vapour phase epitaxy . On top of the Al0.35Ga0.65As barrier a 3.5 nm GaAs quantum well was deposited and to conclude the structure an additional approximate 300 nm Al0.35Ga0.65 As was deposited. The GaAs QW deposited in this manner turns out to be significantly thicker at the bottom of the grooves giving a QWR running along the grooves. During the growth of the barriers an approximately 30 nm wide Ga-rich region is formed at the bottom of the grooves giving a Ga-rich stripe extending from the bottom of each groove to the surface.

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