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Palladium Catalyzed Coupling Reactions: Mechanism of Reductive Elimination. Progress Report, October 1, 1979-September 30, 1980. [Ethane Elimination] (open access)

Palladium Catalyzed Coupling Reactions: Mechanism of Reductive Elimination. Progress Report, October 1, 1979-September 30, 1980. [Ethane Elimination]

The 1,1-reductive elimination of ethane from three cis-bis(phosphine)-dimethylpalladium complexes, L/sub 2/Pd(CH/sub 3/)/sub 2/ (L = PPh/sub 3/, PPh/sub 2/,CH/sub 3/ and L/sub 2/ = Ph/sub 2/PCH/sub 2/CH/sub 2/PPh/sub 2/), and three trans analogs (L = PPh/sub 3/, PPh/sub 2/CH/sub 3/ and L/sub 2/ = 2,11-bis(diphenylphosphinomethyl)benzo(c)phenanthrene (TRANSPHOS)) was carried out. The three cis complexes underwent reductive elimination in the presence of coordinating solvents (DMSO, DMF, and THF). The trans complexes which could isomerize to cis (L = PPh/sub 3/, PPh/sub 2/CH/sub 3/) did so in polar solvents and then underwent reductive elimination. TRANSPHOS dimethylpalladium would not undergo reductive elimination of ethane. The eliminations from the cis isomers were intramolecular and displayed first order kinetics. Although TRANSPHOS dimethylpalladium(II) would not undergo a 1,1-reductive elimination of ethane, the addition of CD/sub 3/I to a DMSO solution of this complex at 25/sup 0/C rapidly produced CD/sub 3/-CH/sub 3/, implicating a transient palladium(IV) intermediate. E- and Z-bromostyrylbis(diphenylmethylphosphine)palladium(0) react with methyl lithium in THF at ambient temperature to give the E- and Z- propenylbenzenes, respectively. At -78/sup 0/C, the intermediate E- and Z-styrylmethylbis(diphenylmethylphosphine)palladium(II) complexes (9a,b) can be isolated. On raising the temperature of solutions of 9a,b in THF, E- and Z-propenylbenzenes are produced. The reductive elimination …
Date: September 1, 1980
Creator: Stille, J. K.
System: The UNT Digital Library
Lead-Zinc-Silver in the Poughkeepsie District and Part of the Upper Uncompahgre and Mineral Point Districts, Ouray and San Juan Counties, Colorado (open access)

Lead-Zinc-Silver in the Poughkeepsie District and Part of the Upper Uncompahgre and Mineral Point Districts, Ouray and San Juan Counties, Colorado

Report issued by the Bureau of Mines over mining districts in Colorado. As noted in the introduction, "in this report the physical features, climate, and ore deposits of the districts are described, and a brief history of mining and production of lead, zinc, and silver is given" (p. 4). This report includes tables, illustrations, and maps.
Date: September 1949
Creator: Hazen, Scott W., Jr.
System: The UNT Digital Library
Mean and Peak Wind Load Reduction on Heliostats (open access)

Mean and Peak Wind Load Reduction on Heliostats

This report presents the results of wind-tunnel tests supported through the Solar Energy Research Institute (SERI) by the Office of Solar Thermal Technology of the US Department of Energy as part of the SERI research effort on innovative concentrators. As gravity loads on drive mechanisms are reduced through stretched-membrane technology, the wind-load contribution of the required drive capacity increases in percentage. Reduction of wind loads can provide economy in support structure and heliostat drive. Wind-tunnel tests have been directed at finding methods to reduce wind loads on heliostats. The tests investigated both mean and peak forces, and moments. A significant increase in ability to predict heliostat wind loads and their reduction within a heliostat field was achieved. In addition, a preliminary review of wind loads on parabolic dish collectors was conducted, resulting in a recommended research program for these type collectors. 42 refs., 38 figs., 1 tab.
Date: September 1, 1987
Creator: Peterka, J. A.; Tan, L.; Bienkiewcz, B. & Cermak, J. E.
System: The UNT Digital Library
Palladium Catalyzed Coupling Reactions: Mechanism of Reductive Elimination. Progress Report, June 1, 1978-September 30, 1979 (open access)

Palladium Catalyzed Coupling Reactions: Mechanism of Reductive Elimination. Progress Report, June 1, 1978-September 30, 1979

The coupling reaction of benzyl halides and organolithium, organotin, or Grignard Reagents is catalyzed by palladium. The sequence of events in the catalytic cycle is oxidative addition of the benzyl halide to palladium(0), methathesis by the organometallic reagent to give a benzyl methyl palladium(II) complex, oxidative addition of the benzyl halide to give a palladium(IV) complex, and reductive elimination of benzyl and methyl to give ethylbenzene. The reductive elimination from palladium bearing an optically active ..cap alpha..-deuteriobenzyl group takes place with retention of configuration at carbon, and is therefore concerted or nearly concerted. Since rho is positive in the catalytic reaction with substituted aryl halides, an oxidative addition, probably during the Pd(II) to Pd(IV) reaction, is the slow step in the catalytic cycle. The intermediate diorganopalladium species can be isolated when the two groups attached to palladium are both methyl or methyl and either cis or trans-..beta..-styryl. The decomposition of these species can be followed by NMR. In the case of methylstyrylpalladium(II) complexes, the reductive elimination gives propenyl benzene with stereospecific retention of double bond geometry. Cis-dimethylbis(diphenylmethylphosphine)palladium(II) does not undergo isomerization to the more stable trans isomer in an inert solvent, and is stable toward reductive elimination up to 50/sup …
Date: September 1, 1979
Creator: Stille, J. K.
System: The UNT Digital Library
Preliminary Report on the Carnotite Deposits of the Old Leyden Coal Mine, Jefferson County, Colorado (open access)

Preliminary Report on the Carnotite Deposits of the Old Leyden Coal Mine, Jefferson County, Colorado

From introduction: Mapping, sampling, and radiometric reconnaissance of the uranium-bearing deposits in the Laramie formation in the vicinity of the Old Leyden coal mine, sec. 28, T. 2 S., R. 71 W., Jefferson County, Colorado (fig. 1), was completed August 10, 1951. Topographic and geologic maps were made of areas approximately 6,000 feet by 3,000 feet (scale 1:2h00), and 1,200 feet by 800 feet (scale 1:600). Underground workings at three clay mines and at the Old Leyden mine were also mapped. With the exception of the 1:600 map, which accompanies this report, these maps will be transmitted later with a more comprehensive report.
Date: September 1951
Creator: McKeown, Frank A. & Gude, James
System: The UNT Digital Library
Geology and Mineralogy of the J.J. Mine, Jo Dandy Area, Montrose County, Colorado (open access)

Geology and Mineralogy of the J.J. Mine, Jo Dandy Area, Montrose County, Colorado

Introduction: Detailed geologic mine mapping and sampling of the J.J. mine in the Jo dandy area, Montrose County, Colo., were undertaken to study a vanadium-uranium ore body in terms of the physical relationships of ore to host rock, the paragenetic sequence of ore minerals, and the sequential development of an oxidized suite of ore minerals from unoxidized ore.
Date: September 1955
Creator: Elston, Donald Parker & Botinelly, Theodore
System: The UNT Digital Library
Large-Scale Geologic Guides to Carnotite Deposits in the Uravan and Gateway Districts, Montrose and Mesa Counties, Colorado (open access)

Large-Scale Geologic Guides to Carnotite Deposits in the Uravan and Gateway Districts, Montrose and Mesa Counties, Colorado

Abstract: Results of detailed mapping of the Salt Wash sandstone member of the Morrison formation in the Uravan and Gateway districts, Montrose and Mesa Counties, Colo., suggest that large areas containing both lenticular bedding in the ore-bearing sandstone and persistently altered mudstone beneath the sandstone are generally favorable for carnotite deposits.
Date: September 1951
Creator: McKay, E. J.
System: The UNT Digital Library
Engineering Report on Drilling in the Sand Wash Basin Intermediate Grade Project (open access)

Engineering Report on Drilling in the Sand Wash Basin Intermediate Grade Project

"This report consists of engineering details, statistics, and logistics of the 19 boreholes drilled in the project. Geophysical logs are included on microfiche in the back of this report." (from Introduction)
Date: September 1980
Creator: Callihan, Michael C.
System: The UNT Digital Library
Environmental Assessment of Remedial Action at the Slick Rock Uranium Mill Tailings Sites, Slick Rock, Colorado. Revision 1 (open access)

Environmental Assessment of Remedial Action at the Slick Rock Uranium Mill Tailings Sites, Slick Rock, Colorado. Revision 1

The Uranium Mill Tailings Radiation Control Act of 1978 (42 USC {section}7901 et seq.), hereafter referred to as the UMTRCA, authorized the US Department of Energy (DOE) to clean up two uranium mill tailings processing sites near Slick Rock, Colorado, in San Miquel County. Contaminated materials cover an estimated 63 acres of the Union Carbide (UC) processing site and 15 ac of the North Continent (NC) processing site. The sites are within 1 mile of each other and are adjacent to the Dolores River. The sites contain concrete foundations of mill buildings, tailings piles, and areas contaminated by windblown and waterborne radioactive tailings materials. The total estimated volume of contaminated materials is approximately 621,300 cubic yards (yd{sup 3}). In addition to the contamination in the two processing site areas, four VPs were found to contain contamination. As a result of the tailings being exposed to the environment, contamination associated with the UC and NC sites has leached into shallow ground water. Surface water has not been affected. The closest residence is approximately 0.3 air mi from either site. The proposed action is to remediate the UC and NC sites by removing all contaminated materials within the designing site boundaries or …
Date: September 1, 1994
Creator: unknown
System: The UNT Digital Library
Chemically Assisted in Situ Recovery of Oil Shale. [Quarterly] Report, April 1, 1993--June 30, 1993 (open access)

Chemically Assisted in Situ Recovery of Oil Shale. [Quarterly] Report, April 1, 1993--June 30, 1993

The objective of this work is to investigate, in the laboratory, the parameters associated with a chemically assisted in situ recovery procedure, using hydrogen chloride (HCI), carbon dioxide (CO{sub 2}), and steam (H{sub 2}0), to obtain data useful to develop a process more economic than existing processes and to report all findings. The technical progress of the project is reported. The project status is that the progress is being made towards being able to run meaningful experiments.
Date: September 1, 1993
Creator: Ramirez, W. F.
System: The UNT Digital Library
Direct Methane Conversion to Methanol. Quarterly Project Status Report, January 1, 1994--March 31, 1994 (open access)

Direct Methane Conversion to Methanol. Quarterly Project Status Report, January 1, 1994--March 31, 1994

We proposed to demonstrate the effectiveness of a catalytic membrane reactor (a ceramic membrane combined with a catalyst) to solely produce methanol by partial oxidation of methane. Methanol is used as a chemical feedstock, gasoline additive, and turbine fuel. Methane partial oxidation using a catalytic membrane reactor has been determined as one of the promising approaches for methanol synthesis from methane. In the original proposal the membrane was used to selectively remove methanol from the reaction zone before carbon oxides form, thus increasing the methanol yield. Methanol synthesis and separation in one step would also make methane more valuable for producing chemicals and fuels. The cooling tube inserted inside the membrane reactor has created a low temperature zone that rapidly quenches the product stream. Both ceramic and metal membranes were tested in this study and similar results were obtained. This membrane reactor system has proved effective for increasing methanol selectivity during CH{sub 4} oxidation. We are currently using this non-isothermal non-permselective membrane reactor, and evaluating modifications to further improve performance. Metal membrane was used to avoid the membrane breakage problem. A series of experiments were carried out in order to optimize the operation of the process. A methanol yield of …
Date: September 1, 1994
Creator: Noble, R. D. & Falconer, J. L.
System: The UNT Digital Library
Evaluation of Aftermarket Fuel Delivery Systems for Natural Gas and Lpg Vehicles (open access)

Evaluation of Aftermarket Fuel Delivery Systems for Natural Gas and Lpg Vehicles

This study was designed to evaluate the effectiveness of aftermarket fuel delivery systems for vehicles fueled by compressed natural gas (CNG) and liquefied petroleum gas (LPG). Most of the CNG and LPG vehicles studied were converted to the alternative fuel after purchase. There are wide variations in the quality of the conversion hardware and the installation. This leads to questions about the overall quality of the converted vehicles, in terms of emissions, safety, and performance. There is a considerable body of emissions data for converted light-duty vehicles, and a smaller amount for medium- and heavy-duty vehicles. However, very few of these data involve real world conditions, and there is growing concern about in-use emissions. This report also attempts to assess factors that could allow in-use emissions to vary from the ``best-case`` results normally reported. The study also addresses issues of fuel supply, fuel composition, performance, safety, and warranty waivers. The report is based on an extensive literature and product survey and on the author`s experience with fuel delivery systems for light-duty vehicles.
Date: September 1, 1992
Creator: Willson, B.
System: The UNT Digital Library
Uranium Hydrogeochemical and Stream Sediment Reconnaissance of the Moab NTMS Quadrangle, Utah/Colorado, Including Concentrations of Forty-Three Additional Elements (open access)

Uranium Hydrogeochemical and Stream Sediment Reconnaissance of the Moab NTMS Quadrangle, Utah/Colorado, Including Concentrations of Forty-Three Additional Elements

Partial abstract: "During the summers of 1976, 1977, and 1978, 442 water and 1755 sediment samples were collected from 1801 locations within the 19 400 km2 area of the Moab quadrangle, Utah and Colorado, by private contractors for the Los Alamos Scientific Laboratory. Water samples were collected from streams, springs, and wells; wet and dry sediment samples were collected both from stream channels and from springs. Each water sample was analyzed for 13 elements, including uranium, and each sediment sample was analyzed for 43 elements, including uranium, thorium, and vanadium. All field and analytical data are listed in the appendixes of this report" (p. 1).
Date: September 1979
Creator: Goff, Sue & Warren, Richard G.
System: The UNT Digital Library
Records of Selected Wells and Springs in the Rulison Project Area, Garfield and Mesa Counties, Colorado. (open access)

Records of Selected Wells and Springs in the Rulison Project Area, Garfield and Mesa Counties, Colorado.

None
Date: September 1969
Creator: Hurr, R. T.; Wilson, W. W.; Welder, F. A. & Emerson, R.L.
System: The UNT Digital Library
Reconnaissance Investigations for Uranium in Black Shale Deposits of the Western States during 1951 and 1952 (open access)

Reconnaissance Investigations for Uranium in Black Shale Deposits of the Western States during 1951 and 1952

Report discussing investigations seeking uranium in deposits of black shale around the geographical areas of the Western States
Date: September 1953
Creator: Duncan, Donald Cave
System: The UNT Digital Library
Geology of Uranium Deposits in Triassic Rocks of the Colorado Plateau (open access)

Geology of Uranium Deposits in Triassic Rocks of the Colorado Plateau

From introduction: The primary object of this work was to aid prospectors and mining men in finding and exploiting new deposits of uranium-bearing ores in the Colorado Plateau region, particularly of those in the Shinarump and Moss Black members of the Chinle formation.
Date: September 1956
Creator: Finch, W. I.
System: The UNT Digital Library
A Systematic Radioactivity Reconnaissance of Part of the North Gilpin County Mining District, Colorado (open access)

A Systematic Radioactivity Reconnaissance of Part of the North Gilpin County Mining District, Colorado

From introduction: The purpose of the investigation was to attempt to correlate anomalous radioactivity and mineral distribution in a metal-mining district that shows a distinct areal pattern of distribution of vein types,
Date: September 1953
Creator: Campbell, Russell H. & Schafer, Max
System: The UNT Digital Library
Carnotite Resources of San Miguel Bench, Montrose County, Colorado (open access)

Carnotite Resources of San Miguel Bench, Montrose County, Colorado

Abstract: San Miguel bench includes about 4 square miles in the southern part of T. 48 N., R. 17 W., New Mexico principal meridian, Montrose County, Colorado. Production of carnotite ore from the area has been about 15, 000 short tons having an estimated average graderof 0. 31 percent U3O8,and 1. 6 percent V2 05 Nearly all of the carnotite deposits occur in a single-continuous sandstone bed near the top of the Salt Wash member of the Jurassic Morrison formation. These deposits consist chiefly of sandstone impregnated with uranium- and vanadium-bearing minerals. They are irregular tabular-shaped masses ranging in size from a few short tons to 30, 000 short tons or more of minable carnotite ore. During the period November 27, 1951, to April 17, 1953, the U. S. Geological Survey drilled 309 holes totaling 92, 194 feet on the San Miguel bench. Reserves total about 43, 000 short tons of material 1 foot or more thick and contain 0,.10 percent or more U30 or 1. 0 percent or more V205. Of these reserves 3, 300 short tons occur in private land. These reserves are in ten deposits found by Geological Survey drilling. Potential reserves (reserves based on geologic evidence …
Date: September 1955
Creator: Alvord, Donald C.
System: The UNT Digital Library
Carnotite Resources of San Miguel Bench, Montrose County, Colorado (open access)

Carnotite Resources of San Miguel Bench, Montrose County, Colorado

Report discussing the San Miguel bench and the production of carnotite from deposits consisting of sandstone with uranium- and vanadium-bearing minerals.
Date: September 1955
Creator: Alvord, Donald C.
System: The UNT Digital Library
Conglomeratic Sandstone Strata at the Base of the Brushy Basin Member of the Morrison Formation as Related to Uranium-vanadium Deposits, Southwestern Colorado and Southeastern Utah (open access)

Conglomeratic Sandstone Strata at the Base of the Brushy Basin Member of the Morrison Formation as Related to Uranium-vanadium Deposits, Southwestern Colorado and Southeastern Utah

A report about strata of conglomeratic sandstone which is localized st the base of the Brushy Basin shale member of the Morrison formation of Jurassic Age. These strata are discrete lithologic units which contain sedimentary structures oriented in a prevailing easterly direction.
Date: September 1955
Creator: Phoenix, David A.
System: The UNT Digital Library
Notes on the Differential Leaching of Uranium, Radium, and Lead From Pitchblende in H2SO4 Solutions (open access)

Notes on the Differential Leaching of Uranium, Radium, and Lead From Pitchblende in H2SO4 Solutions

Report discussing the leaching of uranium, radium and lead from oxidized black Katanga pitchblende. Results of leaching are included.
Date: September 1952
Creator: Phair, George & Levine, Harry
System: The UNT Digital Library
Geology and Mineralogy of the J. J. Mine, Jo Dandy Area, Montrose County, Colorado (open access)

Geology and Mineralogy of the J. J. Mine, Jo Dandy Area, Montrose County, Colorado

A report vanadium-uranium ore in the J. J. mine in Montrose County, Colorado.
Date: September 1955
Creator: Elston, Donald P. & Botinelly, Theodore
System: The UNT Digital Library
Advanced NMR approaches in the characterization of coal. Final technical report, September 1, 1990--August 31, 1993 (open access)

Advanced NMR approaches in the characterization of coal. Final technical report, September 1, 1990--August 31, 1993

This project addressed two main goals and one much smaller one. The main goals were (1) to improve the significance, reliability and information content in high-resolution NMR (nuclear magnetic resonance) characterization of coal samples and (2) to develop chemically informative NMR imaging techniques for coal. The minor goal was to explore advanced features of dynamic nuclear polarization (DNP) as a technique for coal characterization; this included the development of two DNP probes and the examination of DNP characteristics of various carbonaceous samples, including coals. {sup 13}C NMR advances for coal depended on large-sample MAS devices, employing either cross-polarization (CP) or direct polarization (DP) approaches. CP and DP spin dynamics and their relationships to quantitation and spin counting were elucidated. {sup 1}H NMR studies, based on CRAMPS, dipolar dephasing and saturation with perdeuteropyridine, led to a {sup 1}H NMR-based elucidation of chemical functionality in coal. {sup 1}H and {sup 13}C NMR imaging techniques, based on magic-angle spinning and rotating magnetic field gradients, were developed for introducing chemical shift information (hence, chemical detail) into the spatial imaging of coal. The TREV multiple-pulse sequence was found to be useful in the {sup 1}H CRAMPS imaging of samples like coal.
Date: September 30, 1993
Creator: Maciel, G. E.
System: The UNT Digital Library
Evaluation of Aftermarket Fuel Delivery Systems for Natural Gas and Lpg Vehicles (open access)

Evaluation of Aftermarket Fuel Delivery Systems for Natural Gas and Lpg Vehicles

This study was designed to evaluate the effectiveness of aftermarket fuel delivery systems for vehicles fueled by compressed natural gas (CNG) and liquefied petroleum gas (LPG). Most of the CNG and LPG vehicles studied were converted to the alternative fuel after purchase. There are wide variations in the quality of the conversion hardware and the installation. This leads to questions about the overall quality of the converted vehicles, in terms of emissions, safety, and performance. There is a considerable body of emissions data for converted light-duty vehicles, and a smaller amount for medium- and heavy-duty vehicles. However, very few of these data involve real world conditions, and there is growing concern about in-use emissions. This report also attempts to assess factors that could allow in-use emissions to vary from the best-case'' results normally reported. The study also addresses issues of fuel supply, fuel composition, performance, safety, and warranty waivers. The report is based on an extensive literature and product survey and on the author's experience with fuel delivery systems for light-duty vehicles.
Date: September 1, 1992
Creator: Willson, B. (Colorado State Univ., Fort Collins, CO (United States))
System: The UNT Digital Library