VEGETABLE PURGATIVES CONTAINING ANTHRACENE DERIVATIVES
In Part I of this series of papers1 reference was made to a preliminary test on an extract of Senna pod which was found to contain only about 5 per cent. of its theoretical activity. Biological and chemical tests have since been carried out on a number of galenical preparations of senna pod and the results have confirmed that only a small proportion of the activity of the pod is present in these concentrated preparations. The ultimate aim of the work described in this paper has been to devise a method of preparing an extract representing the full activity of the pod from which it was made, and as a result, it has been possible to set out the principles underlying efficient extraction and concentration processes.
VEGETABLE PURGATIVES CONTAINING ANTHRACENE DERIVATIVES
A new kind of anthraquinone compound has been isolated from cascara bark (Rhamnus purshiana). Unlike the normal glycosides it cannot be hydrolysed by heating in acid solution, but on heating in acidified ferric chloride solution aloe-emodin and a second anthraquinone, possibly chrysophanol, are produced. Some of the physical properties are described including the ultra-violet light absorption curve which shows peaks at 268, 296 and 325 mμ. The relationship of this compound to casanthranol and to the chemical assay and biological activity of cascara is discussed.
Study on urea-modified phenol formaldehyde resin adhesive
A reasonable technology to synthesize Urea-Modified Phenol Formaldehyde resins is realized by reacting phenol,urea and formaldehyde.The resin's feasibility is explored.The experiment result of shows that storable stability of the modified resin is good.The curing temperature of PUF resins was 25 ℃,lower than that of PF resins.The curing speed of PUF resins is faster than that of PF resins at the same curing temperature.The physical properties of the birch plywood bonded with PUF resins is similar to that of the birch plywood bonded with normal PF resins.The mechanical properties of the birch plywood bonded with PUF resins can achieve the demands of GB/T9846-1988.Free formaldehyde content of plywood is lower than the E1 level set by GB18580-2001.The cost of the adhesive is lowered for the use of urea,and its comprehensive properties is better than that of PF resins.