Quantitative studies of the role of alkenes during the combustion of alkanes

1970 ◽  
Vol 23 (11) ◽  
pp. 2309 ◽  
Author(s):  
T Berry ◽  
CF Cullis
Keyword(s):  
Molecular Weight ◽  
Major Part ◽  
Reaction Rate ◽  
Intermediate Formation ◽  
Substantial Proportion ◽  
Lower Molecular Weight ◽  
Direct Oxidation ◽  
Quantitative Studies

Studies of the combustion of n-butane in the presence of small amounts of [1-14C]but-1-ene and [2-14C]but-2-ene have enabled the role and importance of the two alkenes in the oxidation of the alkane to be determined quantitatively. Thus at 315�, at a stage when the reaction rate has started to decline, over one-third of the n-butane which has reacted has been oxidized to butenes and nearly two-thirds of these two alkenes has reacted further to give other products. All the larger-ring oxa-heterocyclic products and the major part of the oxirans arise by a mechanism not involving the intermediate formation of C4 alkenes but a substantial proportion of the 2-ethyloxiran and 2,3-dimethyloxiran are formed by the direct oxidation of but-1-ene and but-2-ene respectively. About one-quarter of the C4 ketones and an appreciable part of the lower molecular weight aldehydes also appear to be formed by an alkenic route. The general conclusion which emerges is that at the temperature concerned butenes play an important but not overwhelming role as intermediates in the combustion of n-butane.

THE ROLE OF ADSORPTION IN CONTROLLING THE RATE OF REACTION OF CHLORAMBUCIL WITH PROTEIN

1963 ◽  
Vol 41 (4) ◽  
pp. 931-939 ◽  
Author(s):  
J. H. Linford
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
Bovine Serum Albumin ◽  
Inverse Relationship ◽  
Reaction Rate ◽  
The Other ◽  
Alkylation Reaction ◽  
Rate Of Reaction

Two proteins, haemoglobin and bovine serum albumin, have been studied with respect to their rates of alkylation by chlorambucil in vitro at 37 °C and pH 8.4. The proteins are of nearly the same molecular weight and free carboxylic acid content, but the alkylation reaction is 30 times faster with haemoglobin. On the other hand, the adsorption of chlorambucil by albumin is 20 times greater than that exhibited by haemoglobin. This inverse relationship between extent of adsorption and reaction rate suggests that adsorption protects the chlorambucil from activation in the solvent.

THE ROLE OF WATER IN THE FORMATION OF SODIUM TRIPHOSPHATE BY CALCINATION

1954 ◽  
Vol 32 (12) ◽  
pp. 1100-1111 ◽  
Author(s):  
J. D. McGilvery ◽  
A. E. Scott
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Reaction Rate ◽  
Ionic Diffusion ◽  
Fusion Point ◽  
Rapid Formation

The formation of sodium triphosphate by calcination, below the sodium triphosphate fusion point, of various phosphate mixtures of over-all composition 5Na2O.3P2O5.xH2O was investigated. Water plays an important role, decreasing the amounts of pyrophosphate and high molecular weight polyphosphate impurities and increasing the reaction rate under certain conditions. It is suggested that water catalyzes the reactions by: (1) facilitating ionic diffusion, (2) hydrolyzing —P—O—P—linkages, and (3) assisting in the crystallization of sodium triphosphate. With ortho- and pyro-phosphate mixtures temperatures of about 300 °C. and higher are necessary for the rapid formation of sodium triphosphate. With glasses of the composition 5Na2O.3P2O5 good yields may be obtained at temperatures as low as 250 °C. when water is present.

The role of elastoviscosity in the efficacy of viscosupplementation for osteoarthritis of the knee: A comparison of Hylan G-F 20 and a lower-molecular-weight hyaluronan

1999 ◽  
Vol 21 (9) ◽  
pp. 1549-1562 ◽  
Author(s):  
Manfred Wobig ◽  
Gerhard Bach ◽  
Pieter Beks ◽  
Adalbert Dickhut ◽  
Joost Runzheimer ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Lower Molecular Weight ◽  
Osteoarthritis Of The Knee

Restoration of an Oil-Contaminated St. Lawrence River Shoreline: Bioremediation and Phytoremediation

2001 ◽  
Vol 2001 (1) ◽  
pp. 303-308 ◽  
Author(s):  
Susana Garcia-Blanco ◽  
Moustafa Moteleb ◽  
Makram T. Suidan ◽  
Albert D. Venosa ◽  
Kenneth Lee ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Carbon Number ◽  
Nutrient Addition ◽  
Lower Molecular Weight ◽  
Gas Chromatography Mass Spectrometry ◽  
Oil Hydrocarbons ◽  
Polycyclic Aromatic ◽  
Upper Intertidal ◽  
St Lawrence River

ABSTRACT The purpose of this field study was to evaluate bioremediation and phytoremediation in restoring an oil-contaminated freshwater shoreline. Weathered Mesa light crude oil was released intentionally onto small plots in the upper intertidal zone of a study site located along the St. Lawrence River. Treatments were established to examine the effect of nutrient addition and the role of plants (Scirpus pungens) on the removal of oil constituents from the contaminated plots. Fertilizers under evaluation included sodium nitrate, prilled ammonium nitrate, and triple super phosphate. Composite core samples were collected after 0, 1, 2, 4, 8, 12, 16, and 21 weeks for identification of remaining oil constituents by gas chromatography-mass spectrometry (GC-MS). To account for differences because of physical washout, all oil constituents were normalized to the conservative biomarker hopane. Although bioremediation and phytoremediation treatments achieved slightly better degradation of hydrocarbons than natural attenuation, no statistically significant evidence of stimulation through addition of nutrients or biodegradation enhancement by vegetation was observed. After 21 weeks, reduction of target parent and alkyl-substituted polycyclic aromatic hydrocarbons (PAHs) averaged 32% in all treatments. Reduction of target alkanes was of similar magnitude. The pattern of disappearance of hydrocarbons was characteristic of biodegradation: namely, the lower molecular weight alkanes declined to a greater extent than the higher carbon-number alkanes, as did the lower molecular weight PAHs compared to the higher molecular weight PAHs. Since there was little evidence supporting enhancement of biodegradation by nutrient addition with and without vegetation, it was concluded that oxygen limitation most likely dominated the persistence of oil hydrocarbons on the oil-contaminated plots.

THE ROLE OF ADSORPTION IN CONTROLLING THE RATE OF REACTION OF CHLORAMBUCIL WITH PROTEIN

1963 ◽  
Vol 41 (1) ◽  
pp. 931-939
Author(s):  
J. H. Linford
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
Bovine Serum Albumin ◽  
Inverse Relationship ◽  
Reaction Rate ◽  
The Other ◽  
Alkylation Reaction ◽  
Rate Of Reaction

Two proteins, haemoglobin and bovine serum albumin, have been studied with respect to their rates of alkylation by chlorambucil in vitro at 37 °C and pH 8.4. The proteins are of nearly the same molecular weight and free carboxylic acid content, but the alkylation reaction is 30 times faster with haemoglobin. On the other hand, the adsorption of chlorambucil by albumin is 20 times greater than that exhibited by haemoglobin. This inverse relationship between extent of adsorption and reaction rate suggests that adsorption protects the chlorambucil from activation in the solvent.

LABORATORY STUDY OF GERMAN BUNA S-3 CHEMICAL RUBBER

1949 ◽  
Vol 27f (3) ◽  
pp. 119-142
Author(s):  
J. W. L. Fordham ◽  
A. N. O'Neill ◽  
H. Leverne Williams
Keyword(s):  
Molecular Weight ◽  
Laboratory Study ◽  
Reaction Rate ◽  
General Purpose ◽  
Solution Viscosity ◽  
Dilute Solution ◽  
Tire Rubber ◽  
Methods Of Analysis

The German general purpose tire rubber, Buna S-3, differed from the chemical rubber produced in Canada. The study of the polymerization recipe used for this polymer centered around the role of the regulator in the system. The German technique resulted in a system in which the dilute solution viscosity of the polymer remained relatively constant during the reaction. It was found that this system could be duplicated in the laboratory using the equivalents of the German materials. Methods of analysis for diproxid in solution and in latex were investigated. It was observed that the diproxid disappeared very rapidly from the system and the regulating index was found to be similar to that of tertiary amyl mercaptan and to lie between that of n-dodecyl and n-tetradecyl mercaptan when all were used in the Buna S-3 system. The polymers produced compared favorably with the German polymer as to molecular weight homogeneity, response to heat softening, and other data. Substitution of tertiary amyl mercaptan in the Buna S-3 system resulted in a polymer very similar to that produced using diproxid, and the reaction rate was increased nearly fivefold. The polymer prepared with diproxid and other regulators in this system seemed to be more homogeneous than those prepared by the Mutual formula.

scholarly journals Gel filtration of sialoglycoproteins

1978 ◽  
Vol 173 (1) ◽  
pp. 315-319 ◽  
Author(s):  
J A Alhadeff
Keyword(s):  
Molecular Weight ◽  
Sialic Acid ◽  
Human Liver ◽  
Gel Filtration ◽  
Lower Molecular Weight ◽  
Acid Glycoprotein ◽  
Molecular Weights ◽  
Bovine Submaxillary Mucin

The role of sialic acid in the gel-filtration behaviour of sialoglycoproteins was investigated by using the separated isoenzymes of purified human liver alpha-L-fucosidase and several other well-known sialic acid-containing glycoproteins (fetuin, alpha1-acid glycoprotein, thyroglobulin and bovine submaxillary mucin). For each glycoprotein studied, gel filtration of its desialylated derivative gave an apparent molecular weights much less than that expected just from removal of sialic acid. For the lower-molecular-weight glycoproteins (fetuin and alpha1-acid glyocprotein), gel filtration of the sialylated molecules led to apparent molecular weights much larger than the known values. The data indicate that gel filtration cannot be used for accurately determining the molecular weights of at least some sialoglycoproteins.

Soluble Fibrin Complexes and Fibrinogen Heterogeneity in Diabetes mellitus

1980 ◽  
Vol 44 (03) ◽  
pp. 130-134 ◽  
Author(s):  
E B Tsianos ◽  
N E Stathakis
Keyword(s):  
Diabetes Mellitus ◽  
Molecular Weight ◽  
Plasma Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Filtration ◽  
Lower Molecular Weight ◽  
Polyacrylamide Gels ◽  
Soluble Fibrin ◽  
Α2 Macroglobulin ◽  
Patients With Diabetes

SummaryThe presence of soluble fibrin complexes (SFC) measured by gel filtration of plasma on 4% agarose columns, fibrinogen heterogeneity on 3.5% SDS-polyacrylamide gels and the concentrations of several plasma proteins were evaluated in 39 patients with diabetes mellitus (DM) and 19 matched control subjects. A small but significant increase of SFC was found in DM (p<0.01). On individual basis 51.2% of the patients had increased SFC (>M + 2 SD of the controls). Polyacrylamide gel electrophoresis of the SFC showed no evidence of cross-linking or proteolysis. Plasma clots formed in the presence of EDTA and trasylol were analysed in SDS-polyacrylamide gels in a normal and two lower molecular weight fibrin bands (band I, II, III). The percentage of band I fibrinogen was in diabetics (65.3 ± 4.7%) lower than that of the controls (71.8 ± 4.5%) (p < 0.01). Fibrinogen levels, antithrombin III, α1-antitrypsin, α2-macroglobulin and plasminogen were significantly increased in DM. We suggest that in DM there is an enhancement of intravascular fibrin formation and accelerated fibrinogen degradation to lower molecular weight forms.

Permeability Enhancing and Chemotactic Activities of Lower Molecular Weight Degradation Products of Human Fibrinogen

1981 ◽  
Vol 45 (01) ◽  
pp. 090-094 ◽  
Author(s):  
Katsuo Sueishi ◽  
Shigeru Nanno ◽  
Kenzo Tanaka
Keyword(s):  
Molecular Weight ◽  
Degradation Products ◽  
Electron Microscopic Observation ◽  
Chemotactic Activity ◽  
Lower Molecular Weight ◽  
Electron Microscopic ◽  
Human Fibrinogen ◽  
Rabbit Skin ◽  
Molecular Weights ◽  
Active Fragments

SummaryFibrinogen degradation products were investigated for leukocyte chemotactic activity and for enhancement of vascular permeability. Both activities increased progressively with plasmin digestion of fibrinogen. Active fragments were partially purified from 24 hr-plasmin digests. Molecular weights of the permeability increasing and chemotactic activity fractions were 25,000-15,000 and 25,000 respectively. Both fractions had much higher activities than the fragment X, Y, D or E. Electron microscopic observation of the small blood vessels in rabbit skin correlated increased permeability with the formation of characteristic gaps between adjoining endothelial cells and their contraction.These findings suggest that lower molecular weight degradation products of fibrinogen may be influential in contributing to granulocytic infiltration and enhanced permeability in lesions characterized by deposits of fibrin and/or fibrinogen.

Monitoring Polymer-Assisted Mechanochemical Cocrystallisation Through in Situ X-Ray Powder Diffraction

2020 ◽  
Author(s):  
Luzia S. Germann ◽  
Sebastian T. Emmerling ◽  
Manuel Wilke ◽  
Robert E. Dinnebier ◽  
Mariarosa Moneghini ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Powder Diffraction ◽  
Reaction Rate ◽  
Polymer Additives ◽  
Time Resolved ◽  
X Ray

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the monitoring of polymer-assisted grinding reactions using <i>in situ</i> X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of used polymer additives.<br>

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