The effect of thermal water aeration and water—rock interaction

This paper aims at determining the behavior of thermal water brought to surface and how this might impact reinjection wells and the rock during reinjection. The biggest problem is that reinjection wells are predisposed to choking. We searched for a method to examine this process, including a model for physico-chemical changes in the water—rock interaction. Two different samples of powdered rock (designated α and β) were analyzed using thermal water samples from production and reinjection wells. The pH shows significant differences between the samples from wells where free water treatment was carried out, and those from the aerated thermal waters, as well as for the rock sample. Basically, a decrease in sediment volume can be obtained by increasing the pH. The salt effect was more coherent. Its result was an interesting case of W-shaped graphs from the producing well. On the other hand there is virtually no difference between the samples with acid titration

Activation of P-P bonds in unsymmetrically substituted diphosphenes

Seit langem werden zweizähnige Liganden in der metallorganischen Chemie, der Koordinationschemie und der Katalyse angewendet. Für die Synthese solcher Liganden haben in neuerer Zeit Additionen an Alkene an Beachtung gewonnen, bei denen simultan zwei Donorgruppen in ein organisches Gerüst eingeführt werden. Mögliche Syntheserouten zu P,P-Donorliganden, die ebenfalls große Bedeutung haben, wurden in der doppelten Substitution 1,2-disubstituierter Olefine oder der Addition der P,P-Bindungen von Diphosphanen an Alkene oder Alkine gefunden. Unsere Gruppe hat unlängst N-heterocyclische Phosphane beschrieben, die sich durch außerordentlich reaktive P-P-Bindungen auszeichnen und mit Alkenen und Alkinen unter Phosphanylphosphanierung zu Hybrid-Bisphosphanen reagieren, die zwei Donorzentren mit unterschiedlichen elektronischen Eigenschaften aufweisen. Verbindungen dieses Typs stoßen auf reges Interesse als Liganden in der Katalyse. Ein Ziel dieser Doktorarbeit soll die Herstellung neuartiger N-heterocyclischer Diphosphane mit reaktiver P-P-Bindung sein, die anstelle eines Diazaphospholenrings aus acyclischen oder auch benzannellierten P-substituierten Diazaphospholen-Derivaten aufgebaut sind. Ziel ist hierbei, weitere Derivate mit polaren und damit reaktiven P-P-Bindungen aufzubauen, deren Donorzentren unterschiedliche stereochemische Eigenschaften haben. Ob die neuartigen Diphosphane P-P-Bindungspolarisation aufweisen und in Folge dessen eine reaktive P-P-Bindungen besitzen, wird am einfachsten durch Untersuchung des P-P-Abstands nachgewiesen. Deswegen ist es nötig, experimentelle Bestimmungen von P-P-Abständen dieser Verbindungen durch Röntgenstrukturuntersuchungen vorzunehmen, weshalb der Erhalt einkristalliner Proben der Zielverbindungen von entscheidender Bedeutung ist. Die Reaktivität der hergestellten Diphosphane gegenüber Alkenen und Alkinen soll untersucht werden. Die erhaltenen 1,2-Bisphosphane sollen in Bezug auf ihre Koordinationseigenschaften weiterhin eingehender durch die Herstellung von Metall-Komplexen untersucht werden. Hierbei wurde festgestellt, dass die Addition der P-P-Bindung an mono- oder disubstituierte Alkine regio- und Z-stereospezifisch unter Bildung eines einzigen Additionsprodukts abläuft. 1,2-Additionsreaktionen des Diphosphans an Fumarsäure-dimethylester beziehungsweise Maleinsäure-diethylester verliefen nicht stereospezifisch, sondern es wurden verschiedene Produkte erhalten. Eine cis-stereospezifische 1,2-Additionsreaktion war dagegen bei der Reaktion des Diphosphans mit Maleimid zu beobachten. Dies kann auf die starre Ringstruktur des Maleimids zurückgeführt werden. Von allen diesen Produkten wurden Komplexe erhalten.Bidentate ligands are widely used in organometallic and coordination chemistry as well as in catalysis. As a rational way to their synthesis, additions to alkenes or alkynes that allow simultaneous introduction of two donors to an organic backbone have recently attracted attention. Analogous approaches to P,P-donor ligands, which are likewise of great significance, can be accessed via double metathesis of activated 1,2-disubstituted olefins, or via addition of the P-P bond of diphosphene to alkene or alkyne. As we had demonstrated some time ago, the more reactive N-heterocyclic phosphine may undergo similar addition reactions to activated alkenes or alkynes to give 1,2-bisphosphines featuring two donor sites with different electronic properties on a saturated and unsaturated C2-backbone. Hybrid chelating ligands of this type have received interest as ligands for specific applications in catalysis. We have now investigated whether a similar chemical behaviour can also be established for other types of diphosphines. For this purpose we have synthesised and characterised benzannulated P-phosphanyl-diazabenzophospholenes and acyclic 1,1-Diamino-diphosphines. A goal is here to develop further derivatives with polar and reactive P-P bond with an electronically different donor centre. The easiest method to establish whether the P-P bond of the new diphosphine exhibits polarity and whether there is reactivity toward to alkynes and alkenes, is to investigate the P-P bond length. Therefore it is necessary to experimentally measure the P-P distances of these compounds by single crystal X-ray diffraction studies. Acquiring single-crystal samples of the target compounds is hence of utmost importance. The reactivity of the new diphosphines towards electron deficient alkynes and alkenes was to be studied, with special emphasis on the regio- and stereoselectivity of the addition step. New 1,2-bisphosphines synthesised in this manner with two sterically and electronically different phosphorus donor centres will be presented. The coordination chemistry of these species was demonstrated by the synthesis of metal complexes. As a result of this work it was found that the addition of unsymmetrical diphosphines to mono- or di-substituted electron poor alkynes is regioselective and Z-stereospecific and generates only one addition product. The addition to maleic or fumaric diesters is not stereospecific but yields a mixture of dl- and meso-isomers. In contrast, the cis-stereochemistry of the double bond is conserved during the addition of diphosphine to maleic imide, presumably as a consequence of the rigidity induced by the cyclic substrate structure

Perfluoro-p-xylene as a new unique monomer for highly stable arylene main-chain ionomers applicable to low-t and high-t fuel cell membranes

In this study, we present the synthesis and the characterization of novel functionalized arylene main-chain ionomers based on perfluoro-p-xylene (PFX). The polymers were prepared by polycondensation of PFX and 4,4'-dihydroxybiphenyl or bisphenol 2,2-bis(4-hydroxyphenyl)-hexafluoropropane (bisphenol AF). After polymerization, the PFX unit was still able to undergo nucleophilic aromatic substitution reaction, which was used to introduce phosphonic acid groups into the polymer via a reaction with tris(trimethylsilyl)phosphite. Furthermore, electrophilic sulfonation of these polymers was possible in the bisphenol unit when using H2SO4/SO3 as the sulfonation agent. The so-obtained water-soluble PFX-based polyelectrolytes showed excellent chemical stability and were blended with polybenzimidazoles. The blend membranes formed flexible and mechanically robust films with excellent chemical and thermal stabilitie