36 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Ethers"  
Results: 1 - 24 next
open access

Pentamethylcyclopentadienyl and bis(trimethylsilyl)amido complexes of the di- and trivalent lanthanides

Description: The reaction of the divalent iodides YbI/sub 2/ and EuI/sub 2/ with NaN(SiMe/sub 3/)/sub 2/ has provided pentane-soluble, monomeric derivatives of the divalent lanthanides. These compounds are isolated as the solvated species Eu(N(SiMe/sub 3/)/sub 2/)/sub 2/L/sub 2/ (L = thf or 1,2-dme), Yb(N(SiMe/sub 3/)/sub 2/)/sub 2/(thf)/sub 1/ /sub 5/ and Yb(N(SiMe/sub 3/)/sub 2/)/sub 2/L/sub 2/ (L = 1,2-dme or OEt/sub 2/), or as the sodium salts NaM(N(SiMe/sub 3/)/sub 2/)/sub 3/ (M = Eu or Yb). The pentam… more
Date: March 1, 1982
Creator: Tilley, T. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Facile reaction/extraction of coal with supercritical fluids. Quarterly technical progress report, January 1-March 31, 1984

Description: Arylmethyl phenyl ethers undergo competing reactions when treated with Lewis acids in benzene solvent. Apparently, benzene is insufficiently reactive to compete with intramolecular (intrapolymer) nucleophiles and, consequently, no increase in solubility accompanies the cleavages of ether links upon addition of benzene. When better nucleophiles, naphthalene and phenanthene, are provided, carbonium ions generated from ether cleavages are capped and the product is lower in molecular weight and mor… more
Date: April 20, 1984
Creator: Venier, C. G. & Squires, T. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Energies of organic compounds. Technical progress report. [Ketals, orthoesters, norbonyl ketals]

Description: Two automated reaction calorimetry systems were built and tested. The first made use of a quartz thermometer probe as the temperature measuring element. The second was constructed using a thermister which was part of a Wheatstone bridge. The off-balance voltage from the bridge was measured using the 6 1/2 digit digital voltmeter, and transferred to the microprocessor. The one disadvantage of the first system is the relatively large size of the quartz sensor. The calorimeter systems were used to… more
Date: February 19, 1981
Creator: Wiberg, K. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Energies of organic compounds. [Polyoxygenated methanes, ketals, orthoesters, cyclopropane derivatives]

Description: Automatic reaction calorimeters were developed. Enthalpies of hydration or hydrolysis were determined for polyoxygenated methanes, ketals, acetals, orthoesters, and alkenes. Trifluoroacetolysis of alkenes was carried out. Enthalpies of acetolysis and combustion of cyclopropane derivatives were also determined. Molecular mechanics calculations were carried out for ketones and ketals. Charge distribution in organic compounds were studied. 31 references. (DLC)
Date: July 1, 1980
Creator: Wiberg, K. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Deploymerization of coal by direct solvent attack. Semi-annual report, April 1, 1983-August 31, 1983

Description: The depolymerization of Illinois No. 6 coal by a series of solvents having different basecities (pK/sub a/) and nucleophilicities (Swain-Scott nu values) showed no dependence on either the basicity of nucleophilicity of the solvents. As expected, the conversion decreases as the temperature of the reaction is reduced, but the lower the reaction temperature, the higher the percentage of amine incorporation becomes in the products. 5 tables.
Date: September 15, 1983
Creator: Larsen, J. W. & Mohammadi, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Exploratory study of coal conversion chemistry. Quarterly report No. 2, August 19, 1981-November 18, 1981. [Hydroxydipnenylmethanes, triphenylmethane, diphenylether]

Description: This report describes work accomplished under two tasks: Task A, mechanisms of donor-solvent coal liquefaction, and Task B, CO/H/sub 2/O conversion systems. Under Task A, we describe additional evidence relating to the question of the mechanism of the iron oxide catalyzed cleavage of hydroxydiphenylmethanes. o-Hydroxydiphenylmethane is relatively more sensitive to catalysis by Fe/sub 3/O/sub 4/, a possible one electron oxidant, and triphenylmethane is relatively more sensitive to catalyzed clea… more
Date: January 29, 1982
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Facile reaction/extraction of coal with supercritical fluids. Quarterly technical progress report, April 1, 1983-June 30, 1983. [In Benzene]

Description: In summary, model studies have provided the following information. An aprotic solvent will be required for both transalkylation and ionic hydrogenation; a non-nucleophilic solvent will be required for ionic hydrogenation; intromolecular reaction will occur in the reactions of phenyl ethers; and in an aromatic solvent, arylation (transalkylation) occurs in preference to ionic hydrogenation. Model studies of the ionic hydrogenation were continued using a copolymer of 1,4-bis(bromomethyl)naphthale… more
Date: September 1, 1983
Creator: Venier, C. G. & Squires, T. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Studies of the effect of selected nondonor solvents on coal liquefaction yields

Description: The objective of this research program was to evaluate the effectiveness of selected nondonor solvents (i.e., solvents that are not generally considered to have hydrogen available for hydrogenolysis reactions) for the solubilization of coals. Principal criteria for selection of candidate solvents were that the compound should be representative of a major chemical class, should be present in reasonable concentration in coal liquid products, and should have the potential to participate in hydroge… more
Date: September 1, 1983
Creator: Jolley, R. L.; Rodgers, B. R.; Benjamin, B. M.; Poutsma, M. L.; Douglas, E. C. & McWhirter, D. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Solvent extraction of phenols from water

Description: Methyl isobutyl ketone (MIBK) and diisopropyl ether (DIPE) have been evaluated as solvents for extraction of phenols, at high dilution, from water. Equilibrium distribution coefficients (K/sub D/) have been measured for phenol, dihydroxybenzenes and trihydroxybenzenes in both solvents as a function of pH. Particularly for the multihydric phenols, MIBK gives substantially higher values of K/sub D/ than does DIPE. The effect of pH can be described quantitatively through a simple ionization model,… more
Date: February 1, 1980
Creator: Greminger, D. C.; Burns, G. P.; Lynn, S.; Hanson, D. H. & King, C. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Gas Phase Radiolysis and Vacuum Ultraviolet Photolysis of Heterocyclic Organic Compounds. Progress Report, Feburary 1, 1979-February 1, 1980

Description: The long-range objective of our research group is to gain a better understanding of the processes by which complex organic molecules react when they absorb large amounts of energy. This progress report describes the results of our recent work in three areas: diradicals derived from heterocyclic compounds; trimethylene diradicals from various sources; and ion-molecule reactions.
Date: January 1, 1980
Creator: Scala, A. A.; Nguyen, D.; Rourke, W. & Caputo, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Methyltrihydroborate complexes of the lanthanides and actinides

Description: Reaction of MC1/sub 4/ (M = Zr, Hf, U, Th, Np) with LiBH/sub 3/CH/sub 3/ in chlorobenzene produces volatile, hexane-soluble M(BH/sub 3/CH/sub 3/)/sub 4/. Crystal structures are monomeric, tetrahedral species. Lewis base adducts prepared include U(BH/sub 3/CH/sub 3/)/sub 4/.THT, Th(BH/sub 3/CH/sub 3/)/sub 4/.L (L = THF (tetrahydrofuran), THT (tetrahydrothiophene), SMe/sub 2/, OMe/sub 2/), U(BH/sub 3/CH/sub 3/)/sub 4/.2L (L = THF, pyridine, NH/sub 3/), Th(BH/sub 3/CH/sub 3/)/sub 4/.2L (L = THF, T… more
Date: November 1, 1984
Creator: Shinomoto, R.S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The Mark III vertex chamber and prototype test results

Description: A vertex chamber has been constructed for use in the Mark III experiment. The chamber is positioned inside the current main drift chamber and will be used to trigger data collection, to aid in vertex reconstruction, and to improve the momentum resolution. This paper discusses the chamber's construction and performance and tests of the prototype.
Date: July 1, 1987
Creator: Grab, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Chemistry and structure of coal derived asphaltenes and preasphaltenes. Quarterly progress report, October-December 1980. [Methyl-o-xylene; methyl anthracene; methyl naphthalene; methyl pyrene; methyl phenyl ether]

Description: Six model compounds of low molecular weight polymers or oligomers of benzene, o-xylene, anthracene, naphthalene, pyrene, and diphenyl ether were synthesized to study the separate effects of ring number, aliphatic substitution and ether oxygen on pyrolysis yield and microstructure. The results of the experiments on the model compounds were not as expected and hard to explain. The polyphenyl and methyl-o-xylene formed fine and coarse mesophases respectively. Methyl naphthalene and methyl anthrace… more
Date: January 1, 1980
Creator: Yen, T.F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Dimethylether: a low velocity, low diffusion drift chamber gas

Description: There are two main motivations to look for a low electron mobility gas: the first is that a low drift velocity relaxes the need to measure drift times with nanosecond (or even subnanosecond) precision; the second is that (in an ideal drift geometry), the capability of resolving two closely spaced tracks depends upon the ratio of electron mobility to ion mobility ..mu../sub e//..mu../sub i/. Since ..mu../sub i/ is rather constant, the way to separate two tracks is to slow down the electrons. Man… more
Date: January 1, 1983
Creator: Villa, F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Enzymatic desulfurization of coal

Description: Our current efforts to develop clean coal technology emphasize the advantages of enzymatic desulfurization techniques and have specifically addressed the potential of using partially-purified extracellular microbial enzymes or commercially available enzymes. Our work is focused on the treatment of model'' organic sulfur compounds such as dibenzothiophene (DBT) and ethylphenylsulfide (EPS). Furthermore, we are designing experiments to facilitate the enzymatic process by means of a hydrated organ… more
Date: December 15, 1988
Creator: Marquis, J.K. (Boston Univ., MA (United States). School of Medicine) & Kitchell, J.P. (Holometrix, Inc., Cambridge, MA (United States))
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Identification and separation of the organic compounds in coal-gasification condensate waters. [5,5 dimethyl hydantoin, dihydroxy benzenes, acetonitrile]

Description: A substantial fraction of the organic solutes in condensate waters from low-temperature coal-gasification processes are not identified by commonly employed analytical techniques, have low distriution coefficients (K/sub C/) into diisopropyl ether (DIPE) or methyl isobutyl ketone (MIBK), and are resistant to biological oxidation. These compounds represent an important wastewater-treatment problem. Analytical techniques were developed to detect these polar compounds, and the liquid-liquid phase e… more
Date: August 1, 1983
Creator: Mohr, D. H. Jr. & King, C. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Assessment of ether and alcohol fuels from coal. Volume 2. Technical report

Description: A unique route for the indirect liquefaction of coal to produce transportation fuel has been evaluated. The resultant fuel includes alkyl tertiary alkyl ethers and higher alcohols, all in the gasoline boiling range. When blended into gasoline, the ether fuel provides several advantages over the lower alcohols: (1) lower chemical oxygen content, (2) less-severe water-separation problems, and (3) reduced front-end volatility effects. The ether fuel also has high-octane quality. Further, it can be… more
Date: March 1, 1983
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The Mark III vertex chamber: Studies using DME

Description: Studies have been performed using a prototype of a pressurized wire vertex chamber with 8 mm diameter straw geometry. A 35 ..mu..m spatial resolution using dimethyl ether (DME) at 1 bar and 30 ..mu..m using argon ethane (50/50 mixture) at 4 bar was obtained. Preliminary studies show the DME to adversely affect such materials as aluminized Mylar and Delrin.
Date: April 1, 1987
Creator: Pitman, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Mark III Vertex Chamber

Description: The design and construction of the new Mark III vertex chamber is described. Initial tests with cosmic rays prove the ability of track reconstruction and yield triplet resolutions below 50 ..mu..m at 3 atm using argon/ethane (50:50). Also performed are studies using a prototype of a pressurized wire vertex chamber with 8 mm diameter straw geometry. Spatial resolution of 35mm was obtained using dimethyl ether (DME) at 1 atm and 30 ..mu..m using argon/ethane (50/50 mixture) at 4 atm. Preliminary … more
Date: July 1, 1987
Creator: Adler, J.; Bolton, T.; Bunnell, K.; Cassell, R.; Cheu, E.; Freese, T. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Enzymatic desulfurization of coal

Description: Our experimental approach focuses on the use of enzymes which catalyze the addition of oxygen to organic compounds. In tailoring the application of these enzymes to coal processing, we are particularly interested in ensuring that oxidation occurs at sulfur and not at carbon-carbon bonds. Previous studies with DBT have shown that the reaction most frequently observed in microbial oxidative pathways is one in which DBT is oxidized at ring carbons. These reactions, as we have said, are accompanied… more
Date: November 7, 1989
Creator: Boyer, Y.N.; Crooker, S.C.; Kitchell, J.P.; Nochur, S.V. (DynaGen, Inc., Cambridge, MA (United States)) & Marquis, J.K. (Boston Univ., MA (United States). School of Medicine)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Unimolecular decay dynamics of internal energy selected molecules. Technical progress report. [Tetramethyldioxetane]

Description: Direct excitation of overtone vibrations in combination with time-resolved spectroscopic detection probes unimolecular processes in new detail. Observing product luminescence produced by the decay of tetramethyldioxetane excited to v = 3, 4, or 5 of the CH stretching vibration yields the unimolecular decay rate directly, provides overtone vibration spectra on a low pressure gas phase molecule, and reveals a new feature to the chemiluminescence kinetics. Laser induced fluorescence experiments to… more
Date: January 1, 1980
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Synthetic fuel combustion: pollutant formation. Soot initiation mechanisms in burning aromatics. Second quarterly report, 1 January 1981-31 March 1981

Description: This is the second Quarterly Technical Report in a research program to study soot formation in the combustion of aromatic hydrocarbons. Experiments will be carried out in a shock tube at 1300 to 2500/sup 0/K, using a variety of optical diagnostics to study the kinetic behavior of reactants, radical intermediates, and products. The data will be interpreted using a computer model of the kinetics and dynamics of the reacting system. In this report, the performance of the vacuum and data collection… more
Date: April 1, 1981
Creator: Tanzawa, T.; Krech, R. H. & Rawlins, W. T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Coal anion structure and chemistry of coal alkylation. Final report, March 1, 1979-February 29, 1980

Description: In accord with Task 1, some ether cleavage reactions were carried out in two different media - potassium/naphthalene/tetrahydrofuran and potassium/ ammonia - so that the merits and demerits of the two methods could be compared. Preliminary results suggest that both systems yield the same products, and that the ammonia medium is more convenient to work with, because of the absence of by-products such as reduced naphthalenes and tetralin. Dialkyl ethers were found to be least reactive compounds w… more
Date: January 1, 1980
Creator: Stock, L.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Synthetic fuel combustion: pollutant formation. Soot initiation mechanisms in burning aromatics. First quarterly report, 19 September-31 December 1980

Description: Although considerable progress has been made in recent years in understanding the phenomenology of soot formation in the combustion of hydrocarbon fuels, relatively little attention has been focused upon aromatic fuels of the types commonly found in coal liquids. In particular, the effects of gas-phase free radicals, formed during combustion, on the kinetics of formation of incipient soot particles have not been characterized. Accordingly, an experimental investigation of the detailed kinetics … more
Date: January 1, 1981
Creator: Rawlins, W. T. & Tanzawa, T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen