No abstract

The antitumor activity of molybdocene dichloride is tested against Ehrlich ascites tumor in CF1 mice. The application of 75 or 100 mg/kg 24 h after transplantation achieves 100% tumor inhibi­tion until day 30. Following the d0 and d1 metallocene dichlorides of titanium and vanadium, molybdocene dichloride is the First analogous d2 system revealing similar antineoplastic properties.

The oil production in Zistersdorf, Austria operated by the Rohölaufsuchungs AG (RAG) has a long history beginning with the first completion in 1937, and a variety of production technologies were applied. The reservoirs here are primarily of Sarmatian sand stones showing good compaction and permeability in lower zones but highly unconsolidated sands and serious sand production in upper formations. The sands in these upper layers are poorly sorted, so it is difficult to realize sand control. In the past, sand production has been handled by metal wire wrap screens combined with gravel packing. Large amounts of finer particles, however, made it necessary to downsize the slot openings in order to protect pumps and jewelry. In consequence, the wells experienced an increase in pressure drop over the screens and the gravel packing, in some cases resulting into production losses of up to 50%. With the newly developed stand-alone ceramic sand screens, this disadvantage could be eliminated, and sand control in the unconsolidated formations was successfully proven in the Gaiselberg 16 well. This paper will present the design of the applied ceramic screen, its deployment underneath the downhole pump and the production data of Gaiselberg 16. The evaluation of productions rates, pressure drops and sand measurements will be discussed and compared with performed sand retention testing. The paper will give an interpretation of the sand retention mechanisms of the ceramic sand screen and its capability to assist the building up of a natural formed gravel pack.

On reaction of (C5H5)MoCl2 (1) with equivalent amounts of Na2S2 in ethanol, (C5H5)2MoS2 (2) is formed together with (C5H5)2MoS4 (3) and separated from 3 by vacuum sublimation. The more stable tetrasulfide 3 is obtained as the main product from 1 or 2 with excess Na2S2 and also from 2 or (C5H5)2Mo(SH)2 (4) with S8 in chloroform. A threemembered ring chelate structure involving side-on bonded S22- ligands and pseudotetrahedrally coordinated Mo+4 central atoms is postulated for 2.

Die Reaktion des Molybdocendichlorids (I) mit äquimolaren Mengen Na2S2 liefert die Titelverbindung (II) neben (III), die durch Vakuumsublimation getrennt werden können.