Steuerung und Regelung von Dampfstrahlverdichtern

Operation and Control of Steam Ejectors On the basis of typical characteristics of steam ejectors the various possibilities for regulating the vacuum are discussed. It is shown that economy in steam consumption can be achieved by OZ-regulation, the savings being proportional to the fluctuating steam pressure and/or counter pressure.     

Hexaazapolycyclen durch selektive Multimethylenierungen mit Dichlormethan und Base oder mit Urotropin

Hexaazapolycycles by Selective Multimethylenations with Dichloromethane and Base or with Hexamethylenetetramine Multiple methylenations of 2-aminomethylbenzimidazole with dichloromethane and methylamine or ammonia or with hexamethylenetetramine lead to highly selective formations of 6 new single bonds to give only a polycyclic bis-spiro-1,5-diazocine 2 or only a polycyclic spiro-1,3,6-triazonine 4 or only a polycyclic 1,3,6,8-tetrazecine derivative 6 . 4 and 6 may be equally well obtained starting with 2-chloromethyl-benzimidazole. All of these selectively formed products are concave cryptands with 6 amino nitrogen atoms. No template metals are used in their syntheses. The reasons for the unusual changes in selectivity are investigated using semi-empirical PM3 calculations and mechanistic considerations. Experimental and spectroscopic details are given.