Of all the trace elements emitted during coal combustion, mercury is most problematic. Mercury from the atmosphere enters into oceanic and terrestrial waters. Part of the inorganic Hg in water is converted into organic Hg (CH3Hg), which is toxic and bioaccumulates in human and animal tissue. The largest source of human-caused mercury air emissions in the U.S is from combustion coal, a dominant fuel used for power generation. The Hg emitted from plants primarily occurs in two forms: elemental Hg and oxidized Hg (Hg2+). The coal chlorine content and ash composition, gas temperature, residence time and presence of different gases will decide the speciation of Hg into Hg0 and Hg2+. For Wyoming coal the concentrations of mercury and chlorine in coal are 120ppb and 140ppb. In order to understand the basic process of formulation of HgCl2 and Hg0 a numerical model is developed in the current work to simulate in the detail i) heating ii) transient pyrolysis of coal and evolution of mercury and chlorine, iii) gas phase oxidation iv) reaction chemistry of Hg and v) heterogeneous oxidation of carbon during isolated coal particle combustion. The model assumes that mercury and chlorine are released as a part of volatiles in the form of elemental mercury and HCl. Homogenous reaction are implemented for the oxidation of mercury. Heterogeneous Hg reactions are ignored. The model investigates the effect of different parameters on the extent of mercury oxidation; particle size, ambient temperature, volatile matter, blending coal with high chlorine coal and feedlot biomass etc,. Mercury oxidation is increased when the coal is blended with feedlot biomass and high chlorine coal and Hg % conversion to HgCl2 increased from 10% to 90% when 20% FB is blended with coal. The ambient temperature has a negative effect on mercury oxidation, an increase in ambient temperature resulted in a decrease in the mercury oxidation. The percentage of oxidized mercury increases from 9% to 50% when the chlorine concentration is increased from 100ppm to 1000ppm. When the temperature is decreased from 1950 K to 950 K, the percentage of mercury oxidized increased from 3% to 27%.

Cotton-gin trash (CGT) was pyrolyzed at different temperatures and reaction times using an externally-heated batch reactor. The average yields of output products (solid/char, liquid/bio-oil, and gaseous) were determined. The heating value (HV) of CGT was measured to be around 15-16 MJ kg- 1 (6500-7000 Btu lb-1). In the first set of tests, CGT was pyrolyzed at 600, 700, and 800°C and at 30, 45, and 60 min reaction period. The maximum char yield of 40% by weight (wt.%) was determined at 600°C and 30 min settings, however, the HV of char was low and almost similar to the HV of CGT. A maximum gas yield of 40 wt.% was measured at 800°C and 60 min and the highest liquid yield of 30 wt.% was determined at 800°C and 30 min. In the modified pyrolysis test, the effects of temperature (500, 600, 700, and 800°C) on the product yield and other properties were investigated. The experiment was performed using the same reactor purged with nitrogen at a rate of 1000 cm3 min-1. Gas yield increased as temperature was increased while the effect was opposite on char yield. The maximum char yield of 38 wt.% was determined at 500°C and 30 min. The char had the largest fraction in the energy output (70-83%) followed by gas (10-20%) and bio-oil (7- 9%). Maximum gas yield of 35 wt.% was determined at 800°C. The average yield of CO, H2 and total hydrocarbons (THC) generally increased with increased temperature but CO2 production decreased. Methane, ethane, and propane dominated the THC. The bio-oil yield at 600°C was the highest at about 30 wt.% among the temperature settings. The HV of bio-oil was low (2-5 MJ kg-1) due to minimal non-HC compounds and high moisture content (MC). A simple energy balance of the process was performed. The process was considered energy intensive due to the high amount of energy input (6100 kJ) while generating a maximum energy output of only 10%. After disregarding the energy used for preparation and pyrolysis, the energy losses ranged from 30-46% while the energy of the output represent between 55-70% of the input energy from CGT.

1. FVP of arylmethylazides (33b¡B34b) via 3,3-sigmatropic rearrangement gave nitrogen-containing heterocyclic compounds (2b¡B4b). FVP of 35 gave 3-benzyl-2-thiophenecarbaldehyde (65) by 1,2 H shift of nitrene 32 followed by hydrolysis. 2. FVP of benzoic 3-(1-propenyl)-2-thiophenecarboxylic anhydride (67) gave 7-hydroxybenzo[b]thiophene (70) and cyclopenteno[b]thiophene (71). Compound 71 is difficult to synthesize by normal organic synthetic methods. The formation of 7-hydroxybenzo[b]thiophene (70) suggesting the existence of 68. 3. FVP of arylimine gave phenanthridine (3)¡B3-methylpyrrolo[2,3-c] quinoline (69) and thieno[2,3-c]quinoline (134). Such a method can synthesize tricyclic products in one step. On the other hand, photolytic study of arylimine gave compounds 156¡B184¡B164¡B180¡B185 and 186.

Flash vacuum pyrolysis of 2-(2-vinylstyryl)furan derivatives via electrocyclization followed by dehydrogenation will give 2-(2-naphthalen-2-yl)furan analogues, on the other hand, FVP of 2-(2-vinylstyryl)furan derivatives via electrocyclization followed by [1,5]-H shift will give 3-(2-furyl)-1,2-dihydronaphthalene analogues. FVP of 2-[2-(4-methoxyphenyl)vinyl]benzo[b]thiophene gave three products: trans-4-(2-benzo[b]thiophen-2-ylvinyl)phenol, benzo[b]naphtha[1,2-d]thiophen-2-ol and 1H-6-thiacyclopenta[c]fluorene.

1. 2-[2-(2vinylphenyl)ethenyl]thiophene ( 30 ) and 2,2-(o-phenylenedivinylene)dithiophene ( 31 ) were studied under pyrolytic and photolytic conditions, photolytic of 30 gave upon bicyclic product 35, whereas photolytic of 31 gave products 37 and 39, FVP of 30 and 31 gave 34 and 37, respectively,which all include naphthalene nucleus. 2. 2-methoxystilbene ( 17 ) and 3-methoxystilbene ( 18 ) were studied under pyrolytic conditions, FVP of 17 gave single product 2-Phenylbenzo[b]furan ( 23 ), FVP of 18 gave 2-phenanthrol ( 27 ), ( 4-phenanthrol ) ( 28 ), trans-3- hydroxystilbene ( 29 ), Fluoren 9 -one ( 30 ) and a pair of isomer 1H-benz[e]indene ( 11a ) and 3H-benz[e]indene (11b).

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The first chapter describe the pyrolytic and photolytic studies of substituted styrylarenes. Flash vacuum pyrolysis (FVP) of (2-(4-methoxystyryl)-N-methylindole) (18) gave (4-vinylphenol) (81)¡B (7-methyl-7H-benzo[c]carbazole) (82)¡B (benzo[c]carbazole) (83)¡B (1,6-dihydrocyclopenta[c]carbazole) (84) and (3,6-dihydrocyclopenta- [c]carbazole) (84'). FVP of 2',3,5-trimethoxystilbene (31) gave 2-(3,5-dihydroxyphenyl)benzo[b]furan) (26) and 2-(3,5-dimethoxy- phenyl)benzo[b]furan (95). FVP of 2-methoxy-4-(methoxymethyl)-1- [2-(4-methoxyphenyl)-1-methylvinyl]benzene (33) gave [2-(4- methoxyphenyl)-3-methylbenzofuran-5-yl]methanol (104)¡B4-(3,5- dimethylbenzofuran-2-yl)phenol (105) and 2-(4-hydroxyphenyl)-3- methylbenzofuran-5-carbaldehyde (106). FVP of 2-(2-chlorostyryl)- benzo[b]furan (44) ¡B2-(2-chlorostyryl)benzo[b]thiophene (45) and 2-(2-chlorostyryl)-N-methylindole (46) gave benzo[b]naphtha[1,2-d]- furan (116)¡Bbenzo[b]naphtho[1,2-d]thiophene (117)¡B7-methyl-7H- benzo[c] carbazole (82) and benzo[c]carbazole (83). FVP of 2-chloro-N-(N-methylindol-2-ylmethylene)aniline (71) gave N-methylindole-2-carbonitrile (124)¡B 7H-indolo[2,3-c]quinoline (125) and indolo[1,2-a]quinoxaline (126). FVP of 2-methoxy -N-(N-methyl- indol-2-ylmethylene)aniline (72) gave N-methylindole-2-carbonitrile (124) ¡B 2-(N-methylindol- 2-yl)benzoxazole (132) and 2-hydroxy- benzonitrile (133). FVP of 2-methylthio-N-(phenylmethylene)aniline (73)¡B2-methylthio-N-(furylmethylene)aniline (74)¡B2-methylthio-N- (benzo[b]thiophen-2-ylmethylene)aniline (75) and 2-methylthio-N- (N-methylindol-2-ylmethylene)aniline (76) gave 2-phenylbenzothiazole (143)¡B2-furylbenzothiazole (144)¡B2-benzo[b]thiophen-2-ylbenzo- thiazole (145)¡B2-(N-methylindol-2-yl)benzothiazole (146)¡B2-(1H- indol-2-yl)benzothiazole (147) and benzothiazole (148).Such a method, via oxygen-carbon bond disconnecting, can synthesize efficiently a nature product, stemofuran A 26. Photolytic study of 2',3,5-trimethoxystilbene (31) gave 1,5,7- trimethoxyphenanthrene) (101). Photolytic studies of 2-(2-chloro- styryl)benzo[b]furan (44) ¡B2-(2-chlorostyryl)benzo[b]thiophene (45) and 2-(2-chlorostyryl)-N-methylindole (46) gave benzo[b]naphtha- [1,2-d]furan (116) and 4-chlorobenzo[b]naphtha[1,2-d]furan (120)¡Bbenzo[b]naphtho[1,2-d]thiophene (117) and 4-chlorobenzo[b]naphtha- [1,2-d]thiophene (120) ¡B7-methyl-7H- benzo[c]carbazole (82) and 4-chloro-7-methyl-7H-benzo[c]carbazole (121). Photolytic studies of 2-methylthio-N-(phenylmethylene)aniline (73)¡B2-methylthio- -N-(furylmethylene)aniline (74)¡B2-methylthio-N-(benzo[b]thiophen-2- ylmethylene)aniline (75) and 2-methylthio-N-(N-methylindol-2- ylmethylene)aniline (76) gave 2-phenylbenzothiazole (143)¡B2-furyl- benzothiazole (144)¡B2-benzo[b]thiophen-2-ylbenzo- thiazole (145)¡B2-(N-methylindol-2-yl)benzothiazole (146)¡B2-(1H-indol-2-yl)benzo- thiazole (147) and 2-(2,4-dimethoxyphenyl)benzothiazole) (60f). Such a method has the potential for preparing drugs and application on material science. (¤G)FVP of 2-inden-1-ylidenemethylthiophene (24) and 2-inden-1-ylidene- methylfuran (25) gave the cyclized products 2-(2'-thienyl)naphthalene (29) and 2-(2'-furyl)naphthalene (32).

1.trans o-methoxystilbene and its derivatives 47a-f had been studied by means of pyrolysis and photolysis. Under pyrolytic conditions, compounds 47a-f gave not only the expected products 52a,c-f, but also their corresponding isomers 53a,c-f . Furthermore, compound 47b gave naphthalene (63) as the major product by opening the furan ring at higher temperature. Under photolytic conditions, compounds 47a-f gave the expected photocyclic products 2a-f and 109a-f.2.Pyrolytic chemistry of N-(N-Methyl-3-indolyl)methyl benzamide (45) hes been studied. Pyrolysis of 45 gave 3-methyl quinoline (38), 4-methyl quinoline (39) and secondary pyrolysis product quinoline (36). 2.Pyrolytic chemistry of N-(N-Methyl-3-indolyl)methyl benzamide (45) hes been studied. Pyrolysis of 45 gave 3-methyl quinoline (38), 4-methyl quinoline (39) and secondary pyrolysis product quinoline (36).

Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Sujit Banerjee; Committee Co-Chair: Wm. James Frederick, Jr.; Committee Member: John D. Muzzy; Committee Member: Kristiina Iisa; Committee Member: Preet Singh. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Long-term dynamics of lake-water total organic carbon (LW-TOC) concentrations in freshwater lakes provide an important perspective on the recent increases in LW-TOC observed in many of these systems and may assist with the identification of natural and anthropogenic drivers of change. This study examines how LW-TOC in Dragsjön, a lake situated in an area with a long history of anthropogenic land use, has changed in response to natural and anthropogenic perturbations throughout the Holocene. To provide a better understanding of the processes involved, a multi-proxy study was conducted and included multi-element geochemistry (17 major and trace elements), biogenic silica, organic matter (OM) content and composition, and the faecal biomarker “coprostanol”. The direct biomarker for anthropogenic presence, “coprostanol”, and a detailed characterisation of OM composition are for the first time applied for tracing changes in LW-TOC. Natural processes contributed to stable LW-TOC concentrations in Dragsjön for most part of the Holocene. Humans were present in the catchment from AD 100 as indicated by coprostanol, but did not begin to affect LW-TOC until c. AD 1500. In the last 500 years LW-TOC steadily declined from 17 to 10 mg L-1 in response to anthropogenic alterations to the terrestrial biomass balance. The increase in LW-TOC during the last 70 years likely represents a recovery from anthropogenic disturbance rather than a baseline shift in response to any of the number of proposed recent stressors. The faecal biomarker coprostanol and OM composition provided information essential for identifying and characterising the effects of anthropogenic disturbance.