scholarly journals Catalytic conversion of methanol to low molecular weight hydrocarbons. [Dissertation]

1979 ◽  
Author(s):  
B.B. Singh
Keyword(s):  
Molecular Weight ◽  
Catalytic Conversion ◽  
Low Molecular Weight

scholarly journals Polyethylene upcycling to long-chain alkylaromatics by tandem hydrogenolysis/aromatization

Science ◽  
2020 ◽  
Vol 370 (6515) ◽  
pp. 437-441 ◽  
Author(s):  
Fan Zhang ◽  
Manhao Zeng ◽  
Ryan D. Yappert ◽  
Jiakai Sun ◽  
Yu-Hsuan Lee ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Waste Disposal ◽  
Reaction Temperature ◽  
Molecular Hydrogen ◽  
Catalytic Conversion ◽  
Weight Percent ◽  
Low Molecular Weight ◽  
Moderate Reaction ◽  
High Yields ◽  
Long Chain

The current scale of plastics production and the accompanying waste disposal problems represent a largely untapped opportunity for chemical upcycling. Tandem catalytic conversion by platinum supported on γ-alumina converts various polyethylene grades in high yields (up to 80 weight percent) to low-molecular-weight liquid/wax products, in the absence of added solvent or molecular hydrogen, with little production of light gases. The major components are valuable long-chain alkylaromatics and alkylnaphthenes (average ~C30, dispersity Ð = 1.1). Coupling exothermic hydrogenolysis with endothermic aromatization renders the overall transformation thermodynamically accessible despite the moderate reaction temperature of 280°C. This approach demonstrates how waste polyolefins can be a viable feedstock for the generation of molecular hydrocarbon products.

CATALYTIC CONVERSION OF METHANOL TO LOW MOLECULAR WEIGHT OLEFINS

1980 ◽  
Vol 4 (6) ◽  
pp. 749-758 ◽  
Author(s):  
B.B. SINGH ◽  
F.N. LIN ◽  
R.G. ANTHONY
Keyword(s):  
Molecular Weight ◽  
Catalytic Conversion ◽  
Low Molecular Weight

A high-performance oil-free backing pump for electron microscopes

1978 ◽  
Vol 36 (1) ◽  
pp. 110-111
Author(s):  
G.K.W. Balkau ◽  
E. Bez ◽  
J.L. Farrant
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Hot Spots ◽  
High Performance ◽  
Carbonaceous Material ◽  
Contamination Rate ◽  
Low Molecular Weight ◽  
Principal Source ◽  
Rotary Pumps ◽  
Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Low-molecular-weight heparin in the prevention and treatment of thromboembolic disorders

1998 ◽  
Vol 1 (5) ◽  
pp. 166-174 ◽  
Author(s):  
Evelyn R Hermes De Santis ◽  
Betsy S Laumeister ◽  
Vidhu Bansal ◽  
Vandana Kataria ◽  
Preeti Loomba ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Low Molecular Weight ◽  
Prevention And Treatment
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