Protium–deuterium exchange of alkylated benzenes in dilute acid at elevated temperatures

1989 ◽  
Vol 67 (11) ◽  
pp. 1744-1747 ◽  
Author(s):  
Nick Henry Werstiuk ◽  
George Timmins

Benzene (1), toluene (2), o-xylene (3), m-xylene (4), p-xylene (5), 1,2,3-trimethylbenzene (6), 1,2,4-trimethylbenzene (7), 1,3,5-trimethylbenzene (8), 1,2,3,4-tetramethylbenzene (9), 1,2,3,5-tetramethylbenzene (10), 1,2,4,5-tetramethylbenzene (11), pentamethylbenzene (12), hexamethylbenzene (13), hexaethylbenzene (14), ethylbenzene (15), and tetralin (16) have been labelled with deuterium by the high temperature – dilute acid (HTDA) method. In dilute DCl/D2O (0.14–0.27 M) at temperatures of 250–285 °C, the ring hydrogens of these compounds equilibrate with the deuterium pool. At temperatures above 250 °C the methyl groups of 3, 4, 5, 6 and 11 undergo slow H/D exchange; the methyl groups of 8, 9, 10, and 13 undergo exchange much more readily and hexamethylbenzene (13) can be readily perlabelled. Hexamethylbenzene exhibits a lower reactivity than 13 at the benzylic sites. Keywords: deuterium, exchange, alkyl groups, benzenes, acid-catalyzed.

1988 ◽  
Vol 66 (9) ◽  
pp. 2309-2312 ◽  
Author(s):  
Nick Henry Werstiuk ◽  
George Timmins

A modified high temperature – dilute acid method is used to synthesize phenylethene-2,2-d2 ("styrene-2,2-d2") (1b), 2-phenylpropene-1,1,3,3,3-d5 ("α-trideuteriomethylstyrene-2,2-d5") (2b), and E-1-phenylpropene-2-d ("trans-β-methylstyrene-2-d") (3b) from phenylethene ("styrene") (1a), 2-phenylpropene ("α-methylstyrene") (2a), and E-1-phenylpropene ("trans-β-methylstyrene") (3a), respectively. The deuteriated substitution product E-1,3-diphenyl-1-butene-2,4,4,4-d4 (4b) is also obtained from 1a. Labelled substitution products 1,3,3-tri-trideuteriomethyl-1-phenylindane-2,2-d11 (5b), 4-trideuteriomethyl-2,4-diphenyl-1-pentene-1,1,3,3,5,5,5-d10 (6b), and E-4-trideuteriomethyl-2,4-diphenyl-2-pentene-1,1,1,3,5,5,5-d10 (7b) are obtained from 2-phenylpropene.


1985 ◽  
Vol 63 (2) ◽  
pp. 530-533 ◽  
Author(s):  
Nick Henry Werstiuk ◽  
George Timmins

A modification of the high temperature – dilute acid (HTDA) method for deuterium labelling of aromatic compounds has been applied to the H–D exchange of a number of cyclic and acyclic alkenes. Cyclopentene, cyclohexene, cyclododecene, and tetramethylethylene have been completely exchanged in excellent yield. 1-Methylcyclopentene and 1-methylcyclohexene have also been perdeuterated and cycloheptene and cyclooctene partially labelled but require spinning band distillation or preparative glpc for separation from rearrangement products. A variety of C5–C8 acyclic alkenes have also been treated under HTDA conditions.


1981 ◽  
Vol 59 (22) ◽  
pp. 3218-3219 ◽  
Author(s):  
Nick Henry Werstiuk ◽  
George Timmins

The high temperature – dilute acid (HTDA) method has been applied to the preparation of perdeuterated polycyclic aromatic hydrocarbons. Naphthalene (1), 1-methylnaphthalene (2), 2-methylnaphthalene (3), anthracene (4), phenanthrene (5), chrysene (6), pyrene (7), benz[a]anthracene (8), benzo[a]pyrene (9), 1,1′-binaphthyl (10), 1,2′-binaphthyl (11), and 2,2′-binaphthyl (12) have been perdeuterated in high yield in dilute DCl–D2O solutions at elevated temperatures (240–280 °C). 2, 3, 10, 11, and 12 also rearrange.


Author(s):  
M. Larsen ◽  
R.G. Rowe ◽  
D.W. Skelly

Microlaminate composites consisting of alternating layers of a high temperature intermetallic compound for elevated temperature strength and a ductile refractory metal for toughening may have uses in aircraft engine turbines. Microstructural stability at elevated temperatures is a crucial requirement for these composites. A microlaminate composite consisting of alternating layers of Cr2Nb and Nb(Cr) was produced by vapor phase deposition. The stability of the layers at elevated temperatures was investigated by cross-sectional TEM.The as-deposited composite consists of layers of a Nb(Cr) solid solution with a composition in atomic percent of 91% Nb and 9% Cr. It has a bcc structure with highly elongated grains. Alternating with this Nb(Cr) layer is the Cr2Nb layer. However, this layer has deposited as a fine grain Cr(Nb) solid solution with a metastable bcc structure and a lattice parameter about half way between that of pure Nb and pure Cr. The atomic composition of this layer is 60% Cr and 40% Nb. The interface between the layers in the as-deposited condition appears very flat (figure 1). After a two hour, 1200 °C heat treatment, the metastable Cr(Nb) layer transforms to the Cr2Nb phase with the C15 cubic structure. Grain coarsening occurs in the Nb(Cr) layer and the interface between the layers roughen. The roughening of the interface is a prelude to an instability of the interface at higher heat treatment temperatures with perturbations of the Cr2Nb grains penetrating into the Nb(Cr) layer.


Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.


Alloy Digest ◽  
2005 ◽  
Vol 54 (12) ◽  

Abstract Wieland K-88 is a copper alloy with very high electrical and thermal conductivity, good strength, and excellent stress relaxation resistance at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CU-738. Producer or source: Wieland Metals Inc.


Alloy Digest ◽  
1956 ◽  
Vol 5 (7) ◽  

Abstract DOWMETAL HZ32XA is a magnesium-thorium-zinc-zirconium alloy having good high temperature creep resistance, and is recommended for applications at elevated temperatures. It is used in the artificially aged condition (T5). This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as heat treating, machining, and joining. Filing Code: Mg-26. Producer or source: The Dow Chemical Company.


Alloy Digest ◽  
1972 ◽  
Vol 21 (7) ◽  

Abstract UDIMET 105 is a nickel-base alloy which was developed for service at elevated temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-175. Producer or source: Special Metals Corporation.


Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  

Abstract CARPENTER L-605 alloy is a nonmagnetic cobalt-base alloy that has good oxidation and corrosion resistance and high strength at elevated temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Co-81. Producer or source: Carpenter.


Alloy Digest ◽  
1981 ◽  
Vol 30 (6) ◽  

Abstract FANSTEEL 85 METAL is a columbium-base alloy characterized by good fabricability at room temperature, good weldability and a good combination of creep strength and oxidation resistance at elevated temperatures. Its applications include missile and rocket components and many other high-temperature parts. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, tensile properties, and bend strength as well as creep. It also includes information on low and high temperature performance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Cb-7. Producer or source: Fansteel Metallurgical Corporation. Originally published December 1963, revised June 1981.


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