The composition of the strong phosphoric acids was studied in the range 68.8 to 86.3y0 phosphorus pentoxide by weight. Improved filter-paper chromatography made possible the q~~a n t i t a t i v e determination of the nine lower members of the series, and occasio~iall~ up to the twelfth member. I t was found that when the strong phosphoric acids are prepared by heating a t 350°C., a dynamic equilibrium between the component acicls is set up which persists when the mixtures are cooled to room temperature. 0111~ linear condensed polyphosphoric acids were present in the range s t~~d i e d .The colnposition corresponding to 100% orthophosphoric acid contains about 6 mole per cent each of pyrophosphoric acid and "free water". AS the mole ratio of water to phosphorus pentoxide decreases, the number of component acids increases. Orthophosphoric acid is present to an appreciable estent in the stronger phosphoric acids. "Hexametaphosphoric acid" is 11ot a separate chemical entity, but a mixture of higher liliear polyphosphoric acids. INTIIODUCTIONThe composition of the strong phosphoric acids,* i.e. acids containing more than 72.4y0 by weight of phosphorus pentoxide, the P?05 content of pure orthophosphoric acid, is a subject of considerable interest which has been repeatedly investigated by wet analytical methods. Difficulties in these methods, however, have set a decided limitation on the qualitative and quantitative conclusions possible. A study of this subject by filter-paper chron~atography was ~~n d e r t a k e n , therefore, in order to obtain further and more specific information about compositions having a mole ratio of water to phosphorus pentoxide between 3.6 and 1.2.I t has been shown by means of paper chromatograph!. that b~, mising orthophosphoric acid with phosphorus pentoxide a t different ratios, and heating the mixture a t 350°C., we obtain a mixture containing o~ll\, linear condensed polyphosphoric acids. No cyclic ones were found. Branched acids, if present, would not be detected, since any ion-n~olecules with branching are expected to hydrolyze immediately upon dissolutio~l (40). A certain characteristic equilibrium mixture exists for ever?; given ratio of water to phosphorus pentoxide.The phosphoric acids are very viscous, so that equilibria are attained very slowly; the end result of cooling is an oil in the range 72 to 82y0 PzOj, a gum in the range 82 to 86yo PPz05, and a brittle glass a t higher P205 concentrations.These acids are merely members of a continuous series of amorphous condensed phosphoric acid mixtures which extends from orthophosphoric acid to pure phosphorus pentoxide (38). These mixtures are hygroscopic and hydrolyze upon standing unless stored in tightly closed pyrex containers. The existence of strong phosphoric acids has been known for many years. Durgin, Lum, and Malowan (14) give a list of several such acids reported libfanzrscript

Reinvestigation of the active nitrogen -methane reaction in the temperature range 45" to 500°C. has confirmed hydrogen cyanide $s the only product, other than hydrogen, formed in measurable amounts. An induction" effect in the hydrogen cyanide production was observed with increase of methane flow rate. This induction decreased with increase of temperature and was shown to be due to concomitant hydrogen atom reactions, since it could be eliminated by addition of hydrogen atoms to the reaction mixture. Reinvestigation of the active nitrogen -ethane reaction over the temperature range -100" to 475OC. also confirmed hydrogen cyanide to be the only measurable product, other than hydrogen, of that reaction. There was some indication that an induction effect was present with ethane, as with methane, and it may be concluded tentatively that both reactions are carried substantially by hydrogen atom reactions. INTRODUCTIONIn a previous study in this laboratory (7), it was observed t h a t the Arrhenius plot for the reaction of active nitrogen with ileopentane showed a marked change of slope, indicative of two activation energies in the range of temperatures used. While there was some reason to believe that this behavior might be due to two reactive species in active nitrogen, one of which is almost certainly atomic nitrogen (4, 5), there remained the possibilities that it resulted from concomitailt hydrogen atom reactions or from different rates of attack by a single species in active nitrogen a t the primary and quaternary carbon atoms in the neopentane molecule. Since methane and ethane are incapable of suffering such different modes of attack, the reactions of active nitrogen with these two hydrocarbons have been reinvestigated over a wider range of conditioils than those used previously (3), in an effort to examine further the possible significance of the two activation energies observed with neopentane. E X P E R I M E N T A LT h e investigations were made with conventional fast-flow techniques. In many experiments with methane, hydrogen atoms were iiltroduced simultaneously with nitrogen atoms. T h e arrangement for doing this is illustrated in Fig. 1, which, with the accompanying legend, serves also to indicate all the essential details of the apparatus currently used in this laboratory for studies on active nitrogen reactions. When necessary, the reaction vessel was surrounded by an electrically heated furnace molded from asbestos or by a plastic vessel to contain an appropriate refrigerant.The nitrogen discharge tube was operated by a 110 v.-5000 v. transformer which fed through a diode rectifier (Raytheon, 866-A-GAA) and a 2000 ohm resistance into two condensers in parallel (each 4 pf., GOO0 v., Aerovox No. 3). 'Manuscript

The reaction of active nitrogen with methanol has been investigated a t several temperatures in the range 30 to 48OoC using a fast-flow system. The only condensable products found in appreciable amou~lts were water and hydrogen cyanide. The overall activation energy is 3.0 and 3.2 kcal/mole and the steric factors 1.3X10-3 and 2.1X10-3 for streamline and turbulent flow respectively. I t is postulated that the mechanism consists of the initial formation of a collision complex, [NCH30H], which breaks down to two fragments, S C H 3 and OH, from which the two condensable products are formed, NCH3 -+ H C N + 2H or Hz &qttack of the r~letharlol n~olecules b y hydrogen atoms resulting from the main reaction occurs t o a lesser extent and is responsible for the production of small quantities of methane, carbon monoxide, and additional water. INTRODUCTIOS

ABS'TIIACTThe preparation of phosphate glasses containing sodiu~il and hydrogen is described. The over-all con~position was calculated from the N a / P ratio of the starting mixture and the 11)-drogen content determined by a zinc oxide ignition. The chemical constit~~tioii was determined paper-chromatographically eiilploying recent improvenients in techniclue.Close resemblance between the molecular weight distributions of the sodium-acid glasses and the strong phosphoric acids is shown by the results, but it is also shown that there is no sharp transition to the molecular weight distribution sho\vn by the sodiunl, potassium, and lithiunl glasses.'The importance of stoichionietry 011 the constitution of glass is discussed, together with the statistical ~nodels from which several theories are deri\,ed to predict the distribution of the polymers in a glass. The theories of Van Wazer and Parlcs, which show the most satisfactory agrectuent with the experinrental results, receive detailed consideration.

The reaction of active nitrogen with ethanol has been investigated in the range 300 to 593 OK using a modified condensed-discharge Wood-Bonhoeffer fast-flow system. The only condensable products found in appreciable amounts were hydrogen cyanide and water. Hydrogen was the main noncondensable product. A very small amount of acetaldehyde was also formed along with traces of ethane, ethylene, methane, acetonitrile, cyanogen, and probably carbon monoxide. T h e overall activation energy is 3.4 kcal/mole. I t is postulated that the mechanism consists of the formation of two fragments NCzH6 and OH, from which the condensable products result as follows:A number of products found in trace quantities are produced by concomitant reactions of the hydrogen atoms with methyl radicals, and with ethanol as well as by disproportionation of ethyl radicals to produce ethane and ethylene. A preliminary study of the reaction of active nitrogen with isopropanol indicated that the energy of activation is in line with the energies of activation of methanol and ethanol.