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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Organotin Compounds in Kenting Coastal Area

Lee, Shu-Hui 10 September 2002 (has links)
The main goal of this project is monitoring of the species and the concentration distribution of organic tin compounds in seawaters, sediments, and fishes nearby the Kenting coastal area. Gas chromatography/flame photometric detector (GC/FPD) was used to analyze organic tin compounds in samples. Results of this study showed that the average concentration of MMT in surface waters ranged from 4.59 to 21.35ng/L, in bottom waters ranged from 10.07 to 23.63ng/L, in sediments ranged from 2.98 to 17.95ng/g dry wt. The average concentration of MBT in surface waters ranged from 0.13 to 3.25ng/L, in bottom waters ranged from ND to 1.03ng/L, in sediments ranged from 0.03 to 0.68ng/g dry wt. The average concentration of DBT in surface waters ranged from 1.10 to 3.98ng/L, in bottom waters ranged from 1.77 to 5.60ng/L, in sediments ranged from 0.53 to 4.38ng/g dry wt. The average concentration of TBT in surface waters ranged from 0.13 to 0.73ng/L, in bottom waters ranged from ND to 1.53ng/L, in sediments ranged from 0.25 to 2.48ng/g dry wt. The concentration of MMT was much higher than other organic tin compounds. No phenyl-tin compounds were detected. In the tissues of fish, the concentrations of organic tin compounds in liver and kidney were higher than those in other tissues. The ratio of TBT to DBT and MBT in muscle tissues was higher than those in liver and kidney tissues. In general , no serious contamination of organic tin compound was observed nearby the Kenting coastal area.
2

Organotins in Benthic Organisms in Chi-Jing Costal Areas of Kaohsiung

Chu, Yu-chung 09 September 2009 (has links)
Kaohsiung Harbor used to be the third largest harbor of the world , and also the biggest one in Taiwan at present. Even though it¡¦s not in the list of ten biggest harbors now, a lot of ship around the world comes frequently. There are also several shipyards and fishing ports in the area of Kaohsiung Harbor, it¡¦s horrible that the harbor area is polluted by organotin compound pollutant. . Following are five major benthic organisms: Distorsio reticularis, Niotha conoidalis, Metapenaeopsis palmensis, Portunus argentatus and Portunus hastatoides. . Monobutyltin(MBT) is almost detected in the sediment of all the stations, and the concentration is between 5.4 and 17.9 ng /g wet wt as tin. Dibutyltin(DBT) is detected in the sediment of all the station, and the concentration is between 9.5 and 12.5 ng /g wet wt as tin. Tributyltin (TBT) is just detected at station D2 with the concentration of 8.7 ng /g wet wt as tin. The organotin in Distorsio reticularis, Niotha conoidalis, Metapenaeopsis palmensis, Portunus argentatus and Portunus hastatoides are obviously accumulated. In Distorsio reticularis, the concentration of TBT is between ND and 112.6 ng /g wet wt as tin. In Niotha conoidalis, the concentration of TBT is between 12.4 and 217.7 ng /g wet wt as tin, in Portunus argentatus, is between 3.0 and 3.4 and inPortunus hastatoides is between 5.5 and 92.1, in Metapenaeopsis palmensis, is between 3.7 and 37.0. In all station, monobutyltin is the main composition of butyltins; TBT concentration is almost less than 100 ng /g wet wt as tin. The concentration of butyltins in all the five major benthic organisms decreases with the increasing sample size. There wasn¡¦t significant variation for organotin concentrations in Metapenaeopsis palmensis collected from each stationsand seasons. The concentration of Portunus argentatus and Portunus hastatoides is higher in April 2008 and January 2008 than in other months. According to many study, the content of organotins in sediment around coastal areas out of harbor is obviously less than other coastal areas of large-scale harbors (Lisbon, Sines, Sagres, Huelva, Cadiz and Trafalgar). The organotin contamination around coastal areas out of harbor is not serious. Base on estimation of amounts, distributions and contents of organotin in organisms, Portunus argentatus and Portunus hastatoides are better bethic organisms than Distorsio reticularis, Niotha conoidalis, and Metapenaeopsis palmensis in all the depth and area. The amount is also huge that Portunus argentatus and Portunus hastatoides are the best indicator organism for this area.
3

The cleavage of unsymmetrical stannanes ...

Sher, Ben Chompter, January 1937 (has links)
Thesis (Ph. D.)--University of Chicago, 1934. / Lithoprinted. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois."
4

Organotin-Oxo Clusters

Kuan, Fong Sheen, mikewood@deakin.edu.au January 2002 (has links)
This thesis reports on the development and expansion of reliable synthetic di-and multi-tin precursors for the assembly of oligomeric organotin-oxo compounds in which the shape, dimension and tin nuclearity can be controlled. The reaction of polymeric diorganotin oxides, (R2SnO)m (R = Me, Et, n-Bu, n-Oct, c-Hex, i-Pr, Ph), with saturated aqueous NH4X solutions (X = F, Cl, Br, I, OAc) in refluxing 1,4-dioxane afforded in high yields dimeric tetraorganodistannoxanes, [R2(X)SnOSn(X)R2]2, and in a few cases diorganotin dihalides or diacetates, R2SnX2. This method appears to be particularly good for the synthesis of halogenated tetraorganodistannoxanes but a less suitable method for the preparation of dicarboxylato tetraorganodistannoxanes. Identification of [R2(OH)SnOSn(X)R2]2 (R = n-Bu; X = Cl, Br) and [R2(OH)SnOSn(X)R2][R2(X)SnOSn(X)R2] suggest a serial substitution mechanism starting from [R2(OH)SnOSn(OH)R2]2. A series of α, ω -bis(triphenylstannyl)alkanes, [Ph3Sn]2(CH2)n (n = 3-8, 10, 12) and some of their derivatives were synthesised and characterised. These α, ω-bis(triphenylstannyl)alkanes, [Ph3Sn]2(CH2)n were converted to the corresponding halides [R(Cl)2Sn]2(CH2)n (R = CH2SiMe3) and subsequently to the polymeric oxides {[R(0)Sn]2(CH2)n}m. Reaction of {[R(O)Sn]2(CH2)n}m with [R(Cl)2Sn]2(CH2)n. (n = 3, n' = 4 and n = 4, n' = 3) in toluene at 100°C results in a mixture of symmetric and asymmetric double ladders, where different spacer chain lengths (n and n') provide the source of asymmetry. The coexistence at high temperature of separate 119Sn NMR signals belonging to symmetric and asymmetric double ladders suggests an equilibrium that is slow on the 119Sn NMR time scale and the position of which is temperature dependent. However, 119Sn NMR spectroscopic experiments of {[R(0)Sn]2(CH2)3}m with [R(Cl)2Sn]2(CH2)n for longer spacers (n - 5, 6, 8, 10, 12) reveal that molecular self-assembly of symmetric spacer-bridged di-tin precursors of equal chain length is preferred over asymmetric species. An ether-bridged di-tin tetrachloride [R(Cl)2Sn(CH2)3]2O (R = CH2SiMe3) and its corresponding polymeric oxide {[R(O)Sn(CH2)3]2O}m were synthesised and characterised. Reaction of [R(Cl)2Sn(CH2)3]2O with {[R(O)Sn(CH2)3]2O}m results in a unique functionalised double ladder {{[RSn(Cl)](CH2)3O(CH2)3[RSn(Cl)]}O}4 whose structure in the solid state was determined by X-ray analysis. Identification of tetrameric functionalised double ladder as well as dimeric and monomeric species suggest the existence of an equilibrium in solution. The feasibility of the functionalised double ladder to form host-guest complexes with a variety of metal cations is investigated using electrospray mass spectrometry (ESMS). Evidence for such complexes is found only for sodium cations. The reaction between {[R(O)Sn]2(CH2)n}m (n = 3, 4, 8, 10) and triflic acid is described. The initial formed products [RSn(CH2)nSnR](OTf)4 are easily hydrolysed. For n = 3, self-assembly leads to a discrete double ladder type structure, {{[RSn(OH)](CH2)3[RSn(H2O)]}O}44OTf, which is the first example of a cationic double ladder. For n ≥ 3, hydrolysis gives polymeric products, as demonstrated by the crystal structure of {[(H2O)(OH)RSn]2(CH2)4-2OTf2H2O}m. Two spacer-bridged terra-tin octachlorides [R(Cl)2Sn(CH2)3Sn(Cl)2]2(CH2)n (R = CH2SiMes; n = 1, 8) and their corresponding polymeric oxides {[R(O)Sn(CH2)3Sn(O)]2(CH2)n}m were successfully synthesised and characterised. Attempts were made to synthesise quadruple ladders from these precursors. Reactions of [R(Cl)2Sn(CH2)3Sn(Cl)2]2CH2 with {[R(O)Sn(CH2)3Sn(O)]2CH2}m or (Y-Bu2SnO)3 result in, mostly insoluble, amorphous solids. Reactions of [R(Cl)2Sn(CH2)3Sn(Cl)2]2(CH2)8 with {[R(O)Sn(CH2)3Sn(O)]2(CH2)8}m or (t-Bu2SnO)s result in new tin-containing species which are presumably oligomeric. The synthesis of a series of alkyl-bridged di-tin hexacarboxylates [(RCO2)3Sn]2(CH2)n (n = 3, 4; R = Ph, c-C6H11, CH3, C1CH2) is also reported. The hydrolysis of these compounds is facile and complex. There appears to be no correlation between spacer chain length and hydrolysis product. However, the conjugate acid strength of the carboxylate does appear to be important. In general only insoluble amorphous polymeric organotin-oxo compounds were obtained.
5

An investigation of the preparation, properties and application of some beta-carboalkoxyethyltin compounds

Parker, L. January 1986 (has links)
No description available.
6

Development of ATAAS, FI-ATAAS and HPLC-FAAS for the determination of heavy metals in the environment

Ellis, Lyndon Anthony January 1997 (has links)
No description available.
7

The synthesis and reactions of 3-tri-n-butylstannyl-2,5-dihydrothiophene-1,1-dioxide

Bew, Sean Patrick January 1994 (has links)
No description available.
8

A novel class of hydride catalysts for hydrogenation reactions

Fu, Qi Jia January 2002 (has links)
No description available.
9

Synthesis of tin(IV) complexes for use as potential catalysts for polyurethane formation

Smith, Suzanne Watson January 1997 (has links)
No description available.
10

Studies of estertin halides

Paterson, Eric Simmers January 1983 (has links)
The preparation and physical properties of the estertin halides X 4-nSn[ (CH2)mCO2R]n, where n = 1 or 2, m = 1, 2 or 3 and R is a alkyl or aryl substituent are reported. During the course of this work the molecular structures of Cℓ3SnCH 2CH2CO2Pri and Cℓ3SnCH 2CH2CO2CO2Et were determined. The preparations of Ph3Sn(CH2)3R compounds, where R is a functional group, are reported. The reactions of these compounds with electrophiles were investigated as a route to organotin halides. Explanations on their reactivity are postulated. The preparation of Ph3Sn[CHRR'] compounds where R and R' are the same or different functional groups, from the reaction of (Ph3Sn) 2S with Hg[CHRR']2 is also reported along with the physical properties and evidence for their particular structures. Investigations into the Lewis acidity of estertin halides were undertaken. Chloride ion acceptor strengths, adduct formation with nitrogen bases and catalysis of allylic rearrangement were used as a basis for the evaluation of the Lewis acidity. Explanations are offered for the various observations made during these studies. Finally the preparations of estertin mercaptides, [Et02C(CH 2)]n Sn(SCH2CO2C8H 17)4-n, where n = 1 or 2 are reported. Comparisons of the P.V.C. stabilising ability of these estertin mercaptides were made with the commercially available octyltin tris-mercaptide. Explanations are offered for the apparent difference in stabilising ability of each of these compounds in thermally processed P.V.C. during oven testing.

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