Tune. 1918 C. U. C. P. ALUMNI JOURNAL 103 



T^BSXRKOTS 



Conducted by Prof. George C. Diekman. 



Corrosion of Metals 



H. W. Doughty, in Jour. Avicr. Chem. Soc, 1917, 39, discusses the matter 

 of corrosive action of moist carbon tetrachloride on metal containers, such as 

 tin cans. He states that such action cannot be due merely to the action of 

 hydrochloric acid, resulting- from the hydrolysis of the organic halogen com- 

 pound, upon the metal, since such action is found to be greatly increased, at 

 least in the case of iron and copper, when ammonia is present. It was also found 

 that the liydrolysis of carbon tetrachloride was greatly accelerated by iron and 

 copper, and likewise by hydrogen and hydroxylions. particularly so at higher 

 temperatures. Experiments made with a number of organic halides in order to 

 determine their action on copper in presence of water and ammonia, showed 

 that in the case of compounds containing a trichlormethyl group, the corrosion 

 was most pronounced, while mon-chlor derivatives developed no appreciable re- 

 action. The author also describes a color reaction for tetrachloroethylene, as 

 follows : If this compound be allowed to remain in contact with water, am- 

 monia and copper, for some time, the watery layer shows a bright-red coloration. 



Determination of Woody Fibre 



J. A. & E. W. Voelcker. in Analyst, 1918. 43 The authors call attention 

 to the fact that in England the customary method for determining "woody fibre," 

 is that devised by Voelcker, in which the hydrolysis of the fibre is effected by 

 means of 2% sulphuric acid and solutions of caustic alkali of 2% strength. They 

 likewise call attention to the fact that in the United States and in Continental 

 countries, the official methods for determination of such fibre, deal with solu- 

 tions of 1.25% strength. It is further stated that with solutions of these varying 

 percentage strengths, discordant results are obtained. This is noted in examining 

 oil cakes containing a quantity of hard husks, where considerable differences 

 were noted. The authors claim that it is not possible to effect complete hydrolysis 

 in palm nut and similar cakes, with solutions of less than 2% strength. The 

 following method is recommended : After extracting the oil from 3 grammes 

 of the specimen to be tested, the residue is boiled with 125 mils of 2% sulphuric 

 acid, for a period of 30 minutes, keeping the volume of liquid constant by addition 

 of water. Water is then added to the liquid to make this measure from 400 to 

 500 mils, and the solid matter allowed to sediment. The clear supernatant liquid 

 is then passed through a linen filter, and the solid matter eventually also trans- 

 ferred to this and thoroughly washed, and later on transferred to the original 

 container and boiled for a period of 30 minutes with caustic alkali solution, 2% 

 strong. The same procedure as before is resorted to, and the residue finally 

 washed with alcohol and dried at 100° C. to constant weight. The ash left after 

 ignition is deducted from the weight of the fibre. 



