Letter from Linus Pauling to J.M.M. Pinkerton. June 8, 1948. Page 1  Larger Images / More Information. 2 pp.  View Transcript

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Activity Listings

• Letter from Beatrice Wulf to W.H. Freeman, W.H. Freeman and Co., RE: The Institute bookstore ordered 10 copies of "General Chemistry" and would like to receive them before the end of the fiscal year, June 30, so that they might close their accounts. Wulf requests that Freeman send the copies. She says that the Paulings are leaving Oxford at the end of the month, but that she doesn't yet have their itinerary. [Filed under LP Manuscripts of Books, 1947b6.1]
• Letter from J. G. Kirkwood, Acting Chairman, Div. of Chemistry and Chemical Engineering, to Dr. Jerome L. Rosenberg, Dept. of Chemistry, Columbia University, RE: States that they have received his application but cannot offer him a spot at Caltech because their laboratories are already over crowded. States they are returning Rosenberg's transcript to Dickinson College and offers to return the copy of “A Proposed Diffusion Method for the Fractionation of High Polymers.” [Memo from B. Wulf to Dr. Corey and Dr. Sturdivant June 1, 1948] [Filed under LP Correspondence: #340.13
• Letter from LP to Dr. J. M. M. Pinkerton, Cavendish Laboratory, University of Cambridge. Handwritten across the top: “To take to Cambridge June 15.” Handwritten below that in the left margin: “File.” [Letters from Dr. J. M. M. Pinkerton to LP May 14, 1948, and June 18, 1948] [Filed under LP Correspondence: #312.13]

  Balliol College

  Oxford

  June 8, 1948

  Dr. J. M. M. Pinkerton

  Cavendish Laboratory

  University of Cambridge

  Cambridge

  Dear Dr. Pinkerton:

  I have been interested to read your letter of 14 May, and have thought about the problem that you mention.

  It seems to me unlikely that association occurs to any significant extent between ethyl acetate molecules, and even if association did occur I believe that dissociation would not involve any significant activation energy. Consequently I suggest that this is not the explanation of your phenomenon.

  On the other hand, it seems likely that there are some states differing in energy by as much as 6 kilocalories per mole because of the difference in orientation around single bonds in the molecule, or around one of the carbon-oxygen resonating bonds. For example, the carbon-carbon bonds in the ethyl group might well show a heat of activation of 5.5 kilocalories per mole for the reaction of rotation of the methyl group through 120°. It has indeed been shown by Gordon and Giauque (J, Gordon and W. F. Giauque, J. Am. Chem. Soc., 70, 1506 (1948), that the potential barrier in ethyl chloride is 4.7 kilocalories per mole, for rotation of the methyl group through 120°. On the other hand, the trigonal symmetry of the methyl group requires that there be no difference in energy between the initial and final states for this reaction, and consequently it is not the reaction that you are interested in--moreover, the zero energy difference is not affected by changes in pressure or temperature occurring in a sound wave. Now the bond between the carbon atom of the carboxyl group and the oxygen atom to which the ethyl group is attached is a single bond with some double bond character, amounting to perhaps 25%. Accordingly an activation energy of the order of 10 kilocalories per mole might be expected for the rotation of the ethoxy group around its bonds, from the coplanar configuration trans to the acetate methyl group to the coplanar configuration cis to this group. The estimate of 10 kilocalories per mole may be a bit high, and consequently 5.5 might be acceptable. Moreover, because of the difference in nature of the methyl group and the oxygen atom (not bonded to ethyl} of the acetate group, an energy difference of about 5.5 or 6 kilocalories per mole between the cis and trans forms would be anticipated. I would suggest that the form trans the acetate methyl would be the more stable. However, I am relying upon structural arguments and my memory on this point. I do not have literature at hand, but I suggest that you look in the book by H. A. Stuart, and see what conclusion he reached about similar compounds from Kerr effect measurements.

  Rotation around the bonds between the ethyl group and the carboxyl oxygen offers another alternative. However, in general, I think, the potential barrier for rotation of this sort is less than one kilocalorie per mole, and accordingly this explanation seems less likely than the other one.

  I am coming to Cambridge to take part in the Barcroft Memorial Conference on hemoglobin. Perhaps it would be possible for me to have a little chat with you at that time. I shall be staying with Professor Roughton.

  Sincerely yours,

  Linus Pauling:par

• Letter from LP to Dr. John Turkevich, Department of Chemistry, Princeton University RE: Writes how he has heard of his textbook on advanced inorganic chemistry, mentions Freeman hopes it will not be long before his manuscript is part of their series, expresses the feeling that there is great need for a good general textbook in that field and hopes his manuscript will join their series. [Letter from Freeman to LP May 24, 1948] [Filed under LP Correspondence: 439.6]
• Letter from LP to Dr. M. Magat RE: LP returns page 12 of the comments after his paper at the Paris meting which is the only page he made changes on. [Filed under: LP Speeches, 1948s.27]
• Letter from LP to Dr. Robert Corey RE: Asks if the figures he requested in April are ready yet. [Note from Corey to LP June 14, 1948] [Filed under LP Correspondence: Box #67.6 file:(Corey, Robert B., 1937, 1943, 1947-1952, 1954-1957, 1960, 1965, 1967-1968, 1971)]
• Letter from LP to Lord Lindsay, Master, Balliol College, Oxford University, RE: Thanks him for the letter of congratulations upon being awarded an honorary doctorate from Oxford. [Letter from Lindsay to LP June 7, 1948] [Filed under LP Correspondence: Box #230.14, file:(L: Correspondence, 1948)]
• Letter from LP to W. H. Freeman, W. H. Freeman and Company RE: Replies with the following list of comments, thinks the list of topics includes too much, says there is a need for a book on instrumental analysis, and answers Freeman's questions. Says a book on chemiCaltechniques would be useful and worth publishing, says also it would be in their basic chemical series, thinks Hayward does not have enough of a background in chemistry to be a senior author, names a few professors who could be authors of such a book, adds more to the list of instrumental analysis to put in the book, and says that his answer is such a confused one that he will try to make a better one later. Adds that he is enclosing a copy of his letter to Turkevich. [Letter from Freeman to LP April 20, 1948] [Filed under LP Correspondence: 439.6]
• Letter from LP to W.H. Freeman, W.H. Freeman and Co., RE: LP is pleased to hear how well Freeman has adhered to his production schedule. He says that next month he and his family are going to the continent for six weeks, after which they will be heading to New York, and that he will be homes soon after attending all three summer meetings of the American Chemical Society. [Filed under LP Manuscripts of Books, 1947b6.1]
• Letter from Nife Batteries to LP RE: Sends a formula for the chemical reaction of nickel cadmium alkaline accumulators. Refers him to the text “Alkaline Accumulators” by Crennel and Lea for further information. [Filed under LP Correspondence: Box #287.15, file:(N: Correspondence, 1948)]
• Letter from Richard C. Tolman to Dr. and Mrs. Manuel Vallarta, Commission de la Investigacion Scientifica, RE: Asks: “Did you receive our invitation to visit us in June? May we expect you?” [Filed under LP Correspondence: 427.8]
• Note from Joseph Koepfli to LP RE: Writes that he had a UNESCO meeting to attend and thus could not come to the Leveridge Lecture. Asks LP to send his travel itinerary before leaving for the U.S.A. Adds that he will be traveling around England after Evans returns from Washington. [Letters from LP to Koepfli June 2, 1948, June 10, 1948] [Filed under LP Correspondence: Box #199.6, file:(Koepfli, Joseph)]
• Pamphlet: Free Enterprise Lecture delivered before the Henry George School of Social Science by Ernest Caldecott, Mister to Peace. LP Peace: Box 4.001, Folder 1.4