errors in composition also contribute to errors in viscosity. When the difference in softening points Of the components x and y are the greatest these errors are the greatest. This is in agreement with the general experimental observations.
"Handbook of Physics and Chemistry", E. V. Conden and H.Odishaw, Ed., p 77, McGraw-Hill, New York. N.Y., 1958. Roeger, A,, M.S. Thesis, The Pennsylvania State University, 1959. Ubbelohde, L., Ullrich, C., Walthi, C., Oe/, Kohle, €&e/, Teer, 11, 684 (1935). Walker. P. L., Jr., Baumbach, D. O., "5th Conference on Carbon," Vol. 2, p 175, Pennsylvania State University, University Park, Pa., June 19-23, 196 1. Wallouch, R. W., Murty, H.N., Heintz, E. A., Carbon, 10, 729 (1972).
Literature Cited Received for review June 21,1977 Accepted August 9,1977
ASTM Method, D-2319-66, 11 (1969). Frank, H. G., Wegener. O., Brenst. Cbem., 39, 195 (1958).
COMMUNICATIONS Effect of Gas Odorants on Compressor Lubricating Oils Natural gas is required by law to be odorized to enable the customers to detect leaks. The odorants generally used are mercaptans, sulfides, or a mixture of both. These odorants are added to the gas at the town border stations, where the level of odorization can be controlled within narrow limits. This method of odorant addition, however, runs into high costs due to a variety of odorizers in operation in the pipeline system of a gas utility. In addition, more manpower is required to check the operation of odorizers and to keep them supplied with odorants. Because of this, the trend in recent years has been for central odorization or transmission line odorization. There are concerns as to the effect of odorized gas on gas compressor lubricating oils as well as on methanol (which is added to lower the freezing point of natural gas) and on triethylene glycol used in gas dehydrators. This paper briefly describes the results obtained. Experimental Details The concentration of odorants in natural gas is 5-10 ppm. In order to determine the long-term effects of odorants, 1 mL of a 50-50 mixture of tert-butyl mercaptan and dimethyl sulfide was added to 9 mL of eight lube oils. This mixture was heated to 180 "C, to simulate the approximate temperature of oils when the compressor is in operation, and then refluxed for 8 h. This was repeated for a reflux time of 16 h. The excess
odorant was then removed by evacuation of the sample and infrared spectra were taken of the remaining sample. This was compared with the infrared spectra of a blank sample. The same procedure was followed with commercial grade methanol and triethylene glycol, except that experiments were conducted a t 80 and 180 "C. Results and Discussion Analysis of infrared spectra of treated and blank oil samples showed no trace of sulfur in any reaction products. Similar negative results were obtained with methanol and triethylene glycol. However, with triethylene glycol, when air was introduced to the reaction mixture, partial oxidation of triethylene glycol took place whereas no oxidation was observed in the absence of air. It is concluded that tert- butyl mercaptan and dimethyl sulfide odorant do not have degradative effects on the compressor lube oils a t the indicated odorant levels. The same is true for methanol and triethylene glycol. Research and Development Centre Saskatchewan Power Corporation Regina, Saskatchewan, Canada
S. V a n D e r H e i j d e n Y.J. Hu Arun V e r m a *
Received for review July 7, 1977 Accepted July 29, 1977
Ind. Eng. Chem., Prod. Res. Dev., Vol. 16, No. 4 , 1977
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