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).

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 (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: According to recent studies, biochar has the potential to improve soil fertility, mitigate climate change, reduce off-site pollution and assist in managing wastes. The application of biochar to soil is not a new concept; Amazonian dark earths are carbon-rich soils with high soil fertility that were created before 1541. Vacuum pyrolysis is a thermo-chemical conversion technique in which biomass is transformed into bio-oil, biochar and non-condensable gas. The objective of this work was to investigate the chemical and physical properties of biochar produced from vacuum pyrolysis of black wattle, vineyard annual prunings and sugar cane bagasse for their potential as soil amendment and adsorbent. The vacuum pyrolysis of black wattle, vineyard prunings and sugar cane bagasse (pyrolysis temperature: 460°C, pressure: 8kPaabs, heating rate: 17°C/min) resulted in biochar yields of 23.5%, 31.0% and 19.7% on a weight basis, respectively. The nature of the biomass had a substantial effect on yields of the products. High ash content combined with high lignin composition led to higher biochar yields for vineyard prunings. The highest surface acidity was observed for sugar cane bagasse (2.3 mmol/g), whereas the lowest surface acidity was observed for vineyard biochar (1.67 mmol/g). Consequently, the pH of the biochars was in the order: vineyard (10.43)> black wattle (9.74)> sugar cane bagasse (6.56). The cation exchange capacities (CEC) of biochars were 122 cmol/kg, 101 cmol/kg and 65 cmol/kg for sugar cane bagasse, black wattle and vineyard, respectively. The electrical conductivities (EC) were highly correlated with feedstock nature. The Ca and K rich vineyard biochar resulted in the highest EC (0.83 dS/m), whilst EC values of black wattle and sugar cane bagasse were 0.67 dS/m and 0.17 dS/m, respectively. Biochars contained substantial amounts of plant-available nutrients, while being low in toxic inorganic content (Pb, As, Cd). The BET surface areas of sugar cane bagasse, black wattle and vineyard were 259 mª/g, 241 mª/g and 91 mª/g, respectively. The adsorption capacity was found to increase with increased contact time and initial solution concentration. The experimental equilibrium time were found to be 3505 min, 1350 min and 150 min for adsorption of 20 mg/L methylene blue solution for vineyard, black wattle and sugar cane bagasse, respectively. Equilibrium data were well fitted to Langmuir and Freundlich isotherms. The maximum adsorption capacities were found to be 15.15 mg/g, 14.49 mg/g and 19.23 mg/g for vineyard, black wattle and sugar cane bagasse when modelled with Langmuir isotherms. The adsorption kinetics was found to follow the pseudo-second order kinetic model. In summary, biochar from sugar cane bagasse is a promising adsorbent for the removal of basic dyes due to its high surface area and microporous structure. This biochar can be applied to slightly acidic soils for nutrient retention and the exchange of nutrients. On the other hand, possessing high amounts of nutrients, biochars from black wattle and vineyard are potential soil amendentment agents. Biochar from black wattle is more beneficial compared to biochar from vineyard due to its higher surface area, microporosity and cation exchange capacity. / AFRIKAANSE OPSOMMING: Volgens onlangse studies, het houtskool die potensiaal om grond vrugbaarheid te verbeter, klimaat verandering te versag, besoedeling te verlaag en ondersteuning te verleen in die bestuur van afval. Die toevoeging van houtskool in grond is nie ‘n nuwe konsep nie; Amazone donker gronde is koolstof ryk gronde met hoë vrugbaarheid wat voor 1541 geskep is. Vakuum pirolise is ‘n termo-chemiese omskakelings tegniek waarin biomassa afgebreek word na bio-olie, houtskool en nie-kondenseerbare gasse. Die doelwit van hierdie werk was om die chemiese en fisiese eienskappe van houtskool, wat geproduseer is deur die vakuum pirolise van swart wattel, jaarlikse wingerd snoeisels, en suikerriet bagasse, vir hulle potensiaal vir grond verbetering en adsorpsie toepassings te ondersoek. Die vakuum pirolise van swart wattel, jaarlikse wingerd snoeisels, en suikerriet bagasse (pirolise temperatuur: 460°C, druk: 8kPaabs, verhittingstempo: 17°C/min) het houtskool opbrengste van 23.5%, 31.0% en 19.7% op massa basis, respektiewelik tot gevolg. Die tipe biomassa het ‘n beduidende effek op die opbrengs van die produkte. Hoë as-inhoud, gekombineer met hoë lignien inhoud, lei tot hoër houtskool opbrengste vir wingerd snoeisels. Die hoogste oppervlak suurheid is gevind vir suikerriet bagasse (2.3 mmol/g), terwyl die laagste waarde gevind is vir die wingerd snoeisels (1.67 mmol/g). Gevolglik, is die pH van die houtskole in die volgorde van: wingerd (10.43) > swart wattle (9.74) > suikerriet bagasse (6.56). Die katioon uitruiling vermoë (CEC) van die houtskole was 122 cmol/kg, 101 cmol/kg and 65 cmol/kg vir suikerriet bagasse, swart wattel en wingerd snoeisels respektiewelik. Die elektriese konduktiwiteite (EC) is gekorreleer met die eienskappe van die biomassas. Die Ca en K ryke wingerd snoeisel houtskool het die hoogste EC waarde (0.83 dS/m) tot gevolg, terwyl die EC waardes vir swart wattel en suikerriet bagasse bepaal is as 0.67 dS/ 0.16 dS/m respektiewelik. Die houtskole het groot hoeveelhede plant-beskikbare voedingstowwe bevat, terwyl dit laag was in toksiese anorganiese stowwe (Pb, As, Cd). Die BET oppervlak areas van suikerriet bagasse, swart wattel en wingerd snoeisels was 259 mª/g, 241 mª/g en 91 mª/g respektiewelik. Daar is gevind dat die adsorpsie kapasiteit toeneem met toenemende kontak tyd met die aanvanklike oplossing. Die eksperimentele ewewigs tye is gevind as 350 min, 1350 min en 150 min vir die adsorpsie van ‘n 20 mg/L metileen blou oplossing vir wingerd snoeisels, swart wattel en suikerriet bagasse, respektiewelik. Die ewewigs data het die Langmuir en Freundlich isoterme goed gepas. Die maksimum adsorpsie kapasiteite is gevind as 15.15 mg/g, 14.9 mg/g en 19.23 mg/g vir wingerd snoeisels, swart wattel en suikerriet bagasse wanneer dit gemodeleer is met Langmuir isoterme. Daar is bevind dat die adsorpsie kinetika ‘n pseudo-tweede orde kintika model volg. In opsomming, houtskool van suikerriet bagasse is ‘n veelbelowende adsorpsie middel vir die verwydering van basiese kleurstowwe, as gevolg van die hoë oppervlak area en mikroporie-struktuur van hierdie houtskool. Dié houtskool kan gebruik word op effense suur gronde vir voedingstof behoud en uitruiling. Aan die ander kant, houtskole van swart wattel en wingerd snoeisels wat hoë hoeveelhede voedingsstowwe bevat, is potensiële grond verbeterings middels. Houtskool afkomstig van swart wattel is meer voordelig as die van wingerd snoeisels, as gevolg van die hoër oppervlak area, mikroporositeit en katioon uitruilings vermoë van die swart wattel houtskool.

Gas-phase electron diffraction (GED) is the only viable technique for the accurate structural study of gas-phase molecules that contain more than ~10 atoms. Recent advances in Edinburgh have made it possible to study larger, more complex, stable molecules using the SARACEN method. This thesis is concerned with obtaining the structures of unstable species, using both standard GED techniques and by developing a new method in which ash vacuum pyrolysis is used to generate short-lived species in situ. In the first part of this thesis nine primary phosphines (R-PH2) with different substituents (R = methyl, vinyl, ethynyl, allenyl, allyl, propargyl, phenyl, benzyl and chloromethyl) are studied by GED. Vinylarsine and vinyldichloroarsine are also studied. Primary phosphines and arsines appear infrequently in the literature owing to their toxicity and high reactivity, especially of the unsaturated systems. The conformational behaviour in these molecules and trends throughout the series are rationalised. As appropriate, comparisons are made to analogous amines and the differences found are discussed. Tertiary phosphines (R3P) are routinely protected by complexation with borane (BH3) and it has been proposed that this technique could be extended to primary phosphines. As an extension of the initial investigation, the GED study of methylphosphine-borane offers an insight into structural changes that occur upon complexation, although attempts to study larger phosphine-borane complexes by GED proved dificult. The structures and bonding trends in a series of phosphineborane adducts are discussed, mainly using the results of ab initio calculations. The second part of the thesis details the implementation of a new, very high temperature nozzle, which allows the generation of short-lived species by pyrolysis. The workings of this nozzle are discussed and the study of the structure of ketene, generated from three different precursors, is detailed. The benzyl radical has also been studied, and a preliminary GED structure is presented. As a result of this work the molecular structures of Meldrum's acid and dibenzylsulfone are also presented, having been determined in the gas phase for the first time.

The thesis is divided into three chapters Chapter 1¡BFlash vacuum pyrolysis of 2-chloro-N-arenylideneaniline gave quinolines by the intromolecular cyclization. And then, flash vacuum pyrolysis of 2-methoxy-N-arenylideneaniline gave the benzothiazole products by the bond cleavage and the radical reaction. Chapter 2¡BFlash vacuum pyrolysis of 32 gave Stemofuran C. And then, flash vacuum pyrolysis of 33 gave 31 which belonging to the former compound of E6 reported on the paper. We also found that we also could get 2-phenylbenzofuran by flash vacuum pyrolysis of 44. Chapter 3¡BFlash vacuum pyrolysis of furylmethyl benzoates¡Bbenzo- thienylmethyl benzoates and N-methylpyrrolylmethyl benzoates gave the corresponding products by the interconversion between vinylcarbene and cyclopropene.

£¸¡B Pyrolysis of 2-methoxy-2¡¦-methylthiostilbene (22a) and 2,2¡¦-di(methylthio)stilbene (22b) gave not only polycyclic aromatic hydrocarbons (PAH) 17¡B18¡B2, but also the products 33, 34. In addition, photolysis of 22a¡B22b¡B2,2¡¦-dimethoxy stilbene (13) gave photocyclic products 31¡B40¡B12¡B45¡B46. ¤G¡B Pyrolysis of 2-dimethylamino-N-(arenylidene)anilines (20a-f) gave not only 1-methyl-2-arylbenzimidazole (25a-f), but also gave 2-arylquinoxaline (26a-e). Furthermore, compound 20f gave 37 and 25f, but didn't give 26f. ¤T¡B Pyrolysis of benzoic 1,2-dimethyl-3-indolyl anhydride gave 1,2-dimethylindole (19) ¡B3-methylquinoline (30) ¡B4-methylquinoline (31).

(¤@) Pyrolysis of 1,2-bis(3-methoxy-2-naphthyl)ethene (35) gave polycyclic aromatic hydrocarbons (PAH) 42¡B43¡B44 and 45. In addition, photolysis of 35 gave photocyclic products 50. (¤G) Photolysis of £\-azidotoluene (35) and 2-azido1-(2-furanyl)ethanone(45) gave dimer products benzylbenzene (51)¡B2-(furan-2-carbon-yl)-amino-1-(2-furyl)ethan-one (60) and 2-(2-formylfuranyl)-4-(2-furan-yl)-imidazole (48).

Gas-phase thermolysis is a long-known and well established method for the preparation of reactive species. It is, however, limited to relatively volatile substances, which are easily vaporised. In the present work, the solution-spray technique for preparative scale was developed. With this technique, it is possible to subject low-volatile substances, which hardly vaporise even under high-vacuum conditions, to gas-phase thermolysis. By utilising oil nozzles used in heating and burner systems, it was possible to integrate a stable solution-spray into the existing flash-vacuum-pyrolysis system. The influence of several variables, such as flow-rate, pressure, temperature and solvent was determined. The solution-spray technique was applied in [3,3]-sigmatropic rearrangements of certain propargyl thiocyanates to the corresponding allenyl isothiocyanates. Furthermore, the parent compound propa-1,2-dienyl isothiocyanate was reacted with various sterically demanding primary and secondary amines to form 2-amino-1,3-thiazoles in moderate to excellent yields. Based on this, a catalyst-free four-center three-component reaction was developed. 2-Amino-1,3-thiazoles with complex substituents in 5-position at the heterocyclic ring are formed. Reaction mechanisms are discussed to explain the occurance of a highly substituted 1,3-thiazine structure. The influence of reaction temperature, concentrations and solvent were determined and are also discussed. It was shown that 2-amino-5-methyl-1,3-thiazoles are the apparently first aromatic substance class, that readily undergoes Prins-type 1,3-dioxane ring-formation. / Die Gasphasenthermolyse ist eine lang bekannte und etablierte Methodik zur Synthese reaktiver Spezies. Sie ist allerdings auf flüchtige Substanzen mit einer guten Verdampfbarkeit beschränkt. Für schwerflüchtige Verbindungen, welche sich selbst im Hochvakuum nur mäßig oder gar nicht in die Gasphase bringen lassen, wurde in der vorliegenden Arbeit die Solution-Spray-Technik für die Anwendung im präparativen Maßstab entwickelt. Unter Verwendung von Ölzerstäuberdüsen, wie sie in der Heizungs- und Brennertechnik Anwendung finden, wurde die Erzeugung eines stabilen Lösungs-Sprays in die vorhandene Blitzvakuumpyrolyse-Technik integriert. Der Einfluss verschiedener Variablen, wie Flussrate, Druck, Temperatur und Lösungsmittel wurde untersucht. Die Solution-Spray-Technik wurde für die [3,3]-sigmatrope Umlagerung bestimmter Propargylthiocyanate zu Allenyl-isothiocyanaten angewendet. Des Weiteren wurde Propa-1,2-dienylisothiocyanat – das einfachste Allenylisothiocyanat – mit diversen sterisch anspruchsvollen primären und sekundären Aminen in mäßigen bis exzellenten Ausbeuten zu 2-Amino-1,3-thiazolen umgesetzt. Darauf aufbauend konnte eine Vier-Zentren-drei-Komponenten-Reaktion entwickelt werden. Es entstehen in hohen Ausbeuten 2-Amino-1,3-thiazole mit komplexen Substituenten an der 5-Position des Heterocyclus. Reaktionsmechanismen werden diskutiert um die alternative Bildung einer hochsubstituierten 1,3-Thiazinstruktur zu erklären. Der Einfluss von Reaktionstemperatur, Konzentration und Lösungsmittel auf das Produktverhältnis wurde ebenfalls untersucht und wird diskutiert. Es konnte gezeigt werden, dass 2-Amino-5-methyl-1,3-thiazole als offenbar erste aromatische Substanzklasse sehr gute Substrate für die Bildung von 1,3-Dioxanen nach Prins darstellen.