Determination of antioxidants in polymeric materials.
A review of methods proposed for the analysis of antioxidants in polymeric materials, cast in the form of a step-by-step examination of the problems involved in any scheme of analysis, with a critical appraisal of the published procedures designed to overcome them.
Methoden zur Identifizierung von Stabilisatoren — Salizylsäurephenylester und Resorcinmonobenzoat
Salizylsaurephenylester und Resorcinmonobenzoat werden in der Kunststoff-Industrie als Stabilisatoren eingesetzt. Mit Hilfe der Dunnschicht-Chromatographie auf Kieselgel-G-Schichten und mit Methylenschlorid oder einem Gemisch von Diisopropylather und Petrolather als Fliesmittel gelingt der Nachweis dieser beiden Verbindungen. Ebenso konnen diese Substanzen auf direktem gas-chromatographischem Wege oder nach der Umesterung an Hand der gebildeten Reaktionsprodukte leicht identifiziert werden. Salizylsaurepheynlester setzt sich bei der Umesterung zu Salizylsauremethylester und Phenol, Resorcinmonobenzoat zu Benzoesauremethylester und Resorcin um. 
 
 
 
Methods for the Identification of Stabilizers Salicylic acid phenylester and resorcinol monobenzoate have been applied as stabilizers in plastic industry. With the help of thinlayer chromatography on kiesel-Gel-G-layers and with methylene chloride or a mixture of diisopropylether and petrolether as developing solvent these two compounds can be identified. Likewise these substances can be identified as such or as products resulting from their interesterification with the help of gas-chromatography. By the interesterification phenyl salicylate is converted to methyl salicylate and phenol and resorcinol monobenzoate to methyl benzoate and resorcinol.
Influence of pressure and fluidization velocity on the hydrodynamics of a fluidized bed containing horizontal tubes
Abstract An experimental investigation of the influence of horizontal tubes on the bubble behaviour and through-flow velocity of gas inside bubbles was carried out and the influence of pressure and fluidization velocity was studied. The visible bubble flow rate and the gas velocity through the bubbles were measured simultaneously in a pressurized fluidized bed, using capacitance and Pitot-static pressures probes respectively. Silica sand with a mean particle diameter of 0.7 mm was fluidized at pressures between 01. and 1.6 MPa, in a bed of 0.2 × 0.3 m cross-section. Six different horizontal tube configurations were used and comparisons were made with results obtained in the same bed operated without tubes. The results from the bed with tubes show that the influence of pressure and fluidization velocity is basically the same as in the bed without tubes; an increase in pressure and fluidization velocity increases the bubble activity. At low excess gas velocities, the influence of immersed tubes on the bubble behaviour is less pronounced than at high excess gas velocities. Measurements and visual observations show that a small tube pitch gives a more uniform distribution of the visible bubble flow over the bed cross-section. At a combination of high pressure, high excess gas velocity and a large tube pitch, a preferred bubble path was observed in the centre of the bed cross-section. The pressure probe measurements show that the through-flow velocity of gas inside the bubbles is in most cases higher when tubes are present in the bed. The through-flow velocity consistently decreases with increasing pressure in the bed without tubes. The tendency is largely the same at a low excess gas velocity when tubes are present, but at a high excess gas velocity the through-flow velocity first decreases and then increases as the pressure is increased.