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Summary Mapping the chemical structures and organization of humic substances is vital for a fundamental understanding of their roles and interactions in the soil. One‐dimensional nuclear magnetic resonance (NMR) techniques have advanced our awareness of the composition of humic materials, but modern developments in two‐dimensional NMR are soon likely to make obsolete reliance on one‐dimensional spectra alone. The advantages of using heteronuclear two‐dimensional NMR spectroscopy are illustrated in this paper in studies of the structural units in a fulvic acid fraction isolated from the Bh horizon of a Podzol. The structures identified from the NMR (at 500 MHz) experiments can be summarized as: mono‐ and dicarboxylic acids (in about equal amounts), with an average chain length of about 10 carbon atoms (these are easily the major components); smaller amounts (about 10–20% of the acids) of esters and alcohols or ethers; some carbohydrate and amino acid residues (evidence from chemical shift data would suggest that these were likely to be in the form of chains); and very small amounts of 1,2‐, 1,4‐, and 1,3,4‐substituted benzenes and of cinnamic acids. The results suggest that applications of heteronuclear and multidimensional NMR spectroscopy will allow considerable progress to be made in understanding the nature of the structural units and their connectivities in humic molecules provided that the heterogeneity of the humic mixtures can first be decreased significantly.

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Trifluorovinyllithium has been synthesised in high yield from 1,1,1,2-tetrafluoroethane (HFC 134a) by treatment with butyllithium at -78 "C, and then treated with a variety of electrophiles in one-pot reactions.

Periluoro-methane-, -%-octane-, and -%-decane-sulphonyl fluoride were prepared from alkanesulphonyl chlorides by electrochemical fluorination. Various derivatives of the fluorocarbonsulphonic acids were made. The long-chain acids were highly surface-active.RECENT patents assigned to the Minnesota Mining and Manufacturing Company on the preparation of perfluoroalkanesulphonyl fluorides prompt us to publish some of our preliminary, very similar, results. The present paper describes the preparation, by the well-known electrochemical procedure of Simons ,2 of perfluoro-methane-, +octane-, and -n-decane-sulphonyl fluoride from the corresponding alkanesulphonyl chloride (which was made from the alkyl bromide via the sodium alkanesulphonate). The acid fluorides were then converted into simple derivatives of the fluorocarbonsulphonic acids.Trifluoromethanesulphonyl fluoride was obtained in 50-60% yield (cf. Gramstad and Haszeldine 3). Yields of perfluoro-n-octane-and -1.2-decane-sulphonyl fluoride were lower (12-15%) and large amounts of sulphur-free material, probably perfluoro-n-octane and perfluoro-n-decane, were obtained, together with smaller amounts of shorter-chain fluorocarbons and some polymeric residue. It appeared that the chlorine atoms of the sulphonyl chlorides were displaced electrolytically, since no apparent reaction took place with anhydrous hydrofluoric acid alone but a chlorine-containing gas was obtained during the fluorination of methanesulphonyl chloride. The yields of the fluorocarbonsulphonyl fluorides could probably be increased by more detailed individual studies.Various salts were prepared from these acid fluorides by treatment with the appropriate aqueous metal hydroxide. The sodium and potassium salts of the C, and C, , acids were almost insoluble in water. However, though salts of strong acids, they were rather more soluble in ethanol than in the more highly ionising solvent, water. They differed from the corresponding perfluorocarboxylates in their much greater thermal stabilities. They melted below 330", and were stable for long periods at 300" but decomposed in air at 350" (over a period of days) with the formation of sulphate ion : perfluorocarboxylic salts, on the other hand, decompose rapidly at about 250" to give 01efin.s.~The free C, acid 5* formed a hydrate sufficiently stable to be distilled from concentrated sulphuric acid. With phosphoric oxide the anhydrous acid gave the anhydride which decomposed partly after a few days, sulphur dioxide being evolved.The C, and C,, acids were not isolated completely pure by distillation of mixtures of their salts with sulphuric acid because of their somewhat comparable volatilities. An aqueous solution of the C,, acid was prepared by treatment of a saturated solution of the sodium salt with an ion-exchange resin (Zeo-Karb 225). The free acid was converted, in sit%, into its anilinium salt. An attempt to hydrolyse the C, sulphonyl fluoride with water at 160" for 60 hr. failed, no reaction taking place. Under milder conditions however, the C, fl...