|The main objective for COST D6 can be summarised as the "Investigation of the opportunities offered by the application of process technologies under extreme or unusual conditions for highly reactive and selective methods in chemical transformations". It aims at possible applications in the process of integrated environmental protection and the synthesis of materials with unconventional properties. The following secondary objectives are established :diagnosis and modelling of processes taking place under extreme and unusual conditions;new highly selective and reactive routes in the synthesis of organic and inorganic compounds;activation of inert substances;hazardous waste treatment;scale-up of laboratory reactors for practical applications.Current statusThe MoU of this Action has been signed by 17 countries. The research is taking place within ten working groups covering the areas of chemistry at high pressure, in supercritical fluids and sonochemistry, as well as chemistry at high temperatures. Presently the ten working groups co-ordinate a total of 70 research groups from the following countries : A (1), B (5), CH (4), CZ (3), D (11), E (1), F (19), GR (2), H (2), I (2), NL (7), P (1), PL (2), S (1), SLO (2), SK (1) and UK (6). In addition, there are three groups (CZ, H, PL) that received direct PECO support and which are also working on COST D6 topics.After a relatively long period used to define the objective of the Action and to build up the Working Groups, the collaborative research started in 1993 and the first results are appearing; nine Working Group meetings have also been organised :The Working Group "Chemical Processes in Liquefied Gases and Supercritical Fluids" (Co-ordinator : R Van Eldik, D) met in Cambridge (UK), Jul 1996.The Working Group on "Studies of homoproteins under extreme conditions of temperature and pressure" (Co-ordinator : C Balny) has met ad hoc on numerous occasions, at informal workshops and international conferences. A WG meeting took place in Leuven (B) in November 1995 and in September 1996, and also during 1996 in Delft (NL) in November and in Chambéry (F) in December. On the latter occasion it was decided to revise the objective and to extend the working group to strengthen its expertise in new expanding areas : high pressure NMR in the study of intramolecular dynamical processes(Prof R Ernst, Zurich, CH); molecular mechanisms of co-operativity, allostery and intramolecular transmission of regulatory signals (Prof G Hervé, Paris, F); conformational equilibria and dynamics of both macromolecular structures and macromolecular interactions with small molecules (Prof G Hui Bon Hoa, Paris, F); the use of pressure to study the domain of stability of micro-organisms (Prof K Ludwig, Heidelberg, D); vibrational investigation of the structure of proteins and protein-lipid interactions, and determination of the effect of high pressure on the secondary structure (Prof L Smeller, Budapest, H); production of thermophilic enzymes and the structural basis of protein thermostability (Prof Tortora, Milan, I); temperature and pressure dependent phase behaviour of model membrane systems (Prof. R Winter, Dortmund, D). The main results obtained during the first year of collaboration relate to haem-protein and butyrylcholinesterase conformational change, and to biocatalysis in reversed micelles. For the first time it could be shown that an enzyme retains high activity up to a pressure of 2 kbar. A series of joint publications have appeared.Two Working Groups are active in the use of high-pressure techniques directed towards synthesis and discovery of new molecules (Co-ordinators : F. G. Klärner and B. Chaudret). Part of this work is related to the use of pressure to increase the concentration of gases in solution, leading to faster and more economical reactions and beneficial shift in chemical equilibria. In order to follow such reactions a standard bore 9.4 Tesla NMR microreactor has been built (Dr U. Frey, Lausanne, CH). The reactor has been used at gas pressures up to 1000 bars and temperatures up to 180°C. A mixing unit assures rapid dissolving of the gas in the solution, the equilibrium being achieved within ca. 1 minute. This instrumentation is available to the members of these working groups. A working group meeting was held in Strasbourg (F) in October 1996.Two Working Groups are active in the field of "Sonochemistry" (Co-ordinators : J. L. Luche and C. Petrier) and have met during 1995 in Berlin (D), in September and in Chambéry (F) in December, and during 1996 in Cambridge (UK) in July. In the domain of "Organic sonochemistry : Mechanisms and New Synthetic Applications", it has been observed that Diels-Alder cycloadditions, performed under sonication with various substrates, continue to provide intriguing results. Concerning the sub-group "Fundamentals in sonochemistry" various problems have been studied. In studies starting with the design of generators and efficient transmitting systems, energy measurements have been undertaken with various dosimeters. The distribution in a given reaction vessel was determined using thermal detectors. The origin of the sonochemical effect, generally accepted to be a highly energetic, out-of-equilibrium phenomenon, has received a new interpretation. Primary sonochemically produced species are radicals that may by used to decompose organic matter in water, with possible applications in environmental science. In organic solutions, several types of reactions, e.g. isomerisations and substitutions, were studied, with the purpose of obtaining information on the site where the sonochemical process is initiated and/or propagates.The working group on "Spectroscopic and Analytical Studies at High Temperatures Using Novel Experimental and Theoretical Techniques" met in Paris (F) in March 1995.The scientific evaluation of the results obtained, and an assessment of the benefits of the collaboration and the transfer of research results into practical applications will be performed on 4 June 1997 by two external referees (a well-known expert in the field and an industrial chemist) and two internal referees from the Technical Committee COST Chemistry, on the basis of final reports, joint publications and oral presentations during the final workshop in Santorini (GR), Jun 1997. COST Action D6 will end on 13 Sep 1997 (five years after the signing of the MoU); it is likely that projects of the Action will evolve into the COST Action D10 "Innovative Methods and Techniques for Chemical Transformations".