Search

The objective of this work was to identify and develop directionally solidified ceramic matrix-metal eutectic composites for use uncoated at temperatures of 2400 F and preferably higher in aircraft gas turbines. The primary approach was to discover metal-oxygen systems in which the metal whisker phase would form a self-protective oxide coating on exposure to elevated temperatures. Many different metal-oxygen combinations were melted and examined mostly using prefired slugs held in tungsten wire baskets which were heated by radiation inside a carbon susceptor in argon. Practically all compositions could be directionally solidified successfully inside CVD tungsten tubes partially sealed at their ends. Additives which provided additional oxygen to the melt such as CeO2, Cr2O3 and WO3 were often necessary to increase the metal solubility sufficiently to form a eutectic microstructure. A number of potentially interesting systems, Gd2O3-CeO2-Ta, Y2O3-CeO2-Ta, and Y2O3-CeO2-Y, could not survive a 24 hr exposure to air at 2000 F. The Cr-Al2O3, Cr2O3 system, however, showed a surface attack of only a few mils after an exposure of 60 hrs in air at 2600 F. (Author)

Several modifications of the previously studied HR 600 adhesive were chosen for investigation as addition cured polyimide adhesives for titanium. All of the materials studied were acetylene terminated oligomers which were prepared by reacting an arylenediamine with benzophenonetetracarboxylic dianhydride (BTDA) and capping this product with either 3-aminophenylacetylene (I) or 3-(3- aminophenoxy)phenylacetylene (II), followed by imidizing in a refluxing benzene- cresol mixture or in acetic anhydride. The most promising oligomers from the standpoint of melting point, solubility, flow properties and adhesive strength were those from I, BTDA, and 1,3-di-(aminophenoxy)benzene(III), designated HR 600 DP-2 (HR 600 oligomer), and from II, BTDA, and III, designated HR 650. The present manufacturing cost (labor + materials) of HR 600 oligomer is considerably less than that of HR 650. Measured ambient temperature titanium lap shear strengths have been in excess of 4200 psi for HR 650 and 3600 psi for HR 600 oligomer, and lap shear strengths as high as 2600 psi at 500 F have been measured for both materials. Elevated temperature air aging tests (90 percent RH at 160 F) are very encouraging. Weld-bond fatigue data, Pi-tension titanium honeycomb data and T-peel data are presented and discussed., See also Rept. No. AFML-TR-74-88, ADB000277

In this thesis an orientating investigation is described as a first contribution to the knowledge of the reactivities of monohalogenopyridines towards potassium tert -butoxide in dimethyl sulfoxide (DMSO) and tert -butylalcohol. It is connected with extensive studies carried out to date on the behaviour of halogeno- azahetarenes in other strongly basic media, especially potassium amide in liquid ammonia and lithium piperidide and piperidine in ether.As an introduction a survey is given of mechanisms occurring in reactions of halogenoarenes with hydroxide and alkoxides. Furthermore the physical properties and the most important chemical reactions of the solvent DMSO, to be expected in our investigation, are discussed. Special attention is paid to reactions of the anion of DMSO and of nucleophiles formed from its thermal decomposition, with halogenoarenes and other aromatic compounds (Chapter 1).Various procedures used for carrying out reactions and the analytical methods are described in detail (Chapter 2).Results are given of experiments on tert -butoxylations of 3- and 4- halogenopyridines in DMSO.3-Fluoropyridine yields 3- tert -butoxypyridine and its decomposition product 3-hydroxypyridine by the addition-elimination (AE) mechanism; 3-chloro-, 3-bromoand 3-iodopyridine yield 3- tert -butoxy- and 3-hydroxypyridine together with the cinesubstitution products 4- tert -butoxy- and 4-hydroxypyridine by the EA- mechanism via 3,4-didehydropyridine; ratio of 3- and 4-substituted products 1: 2. As by-products from the latter reactions 4-hydroxy-3-(methylthio)pyridine, 1-(4'- pyridyl)-4-pyridone and 4-aminopyridine are isolated.4-Fluoropyridine again only gives 4-substituted pyridines. The other 4-halogenopyridines yield the same products as obtained from the 3-halogenopyridines. The ratios of 3- and 4-substituted products are different however, 4-chloro- and 4-iodopyridine reacting by both the EA- and AE-mechanisms.In tert -butylalcohol, in which solvent the basic propert

Studies were undertaken to examine the possiblility of attaching highly reactive groupings directly to alkyl carbons by the reaction of alkenes with mercury compounds, e.g. Hg(ClO4)2. Some presumptive evidence for the formation of -C(R)2-(ClO4) and -C(R)2-NF2 containing compounds was developed, and a number of intermediates were synthesized.

Ultraviolet, infrared, and Raman spectra have been determined for the products of the reaction of o-chlorobenzylidenamalononitrile (CS) and 2- diethylaminoethyl mercaptan (DEAEM). Structures for two of the products, CS(DEAEM)2 and (CS)2DEAEM, are given, and their spectral characteristics are discussed. Reactions were followed in the ultraviolet by observing the changes occurring in the spectrum with time. The order of addition to CS in the case of the product CS(DEAEM)2, as observed by ultraviolet, is first, the addition to the double bond, and second, addition to the nitrile.

The paper describes the preparation of a series of alkanolamines (HO- R-NH2) bearing one or two cyanoethyl (-C2H4CN) groups on the amino nitrogen. Choice of reaction conditions and certain structural features determine whether mono- or disubstitution occurs, and when both products are formed, the mixture may be conveniently analysed by non-aqueous titration. All products have been characterised as p-nitrobenzoyl derivatives., Pub. in Synthesis, n12 p650-652 Dec 1971.

Bisdiazoterephthalaldehyde, para-bisdiazobenzoylbenzene and meta-bis-diazobenzoylbenzene were synthesized as dicarbene precursors. Simultaneous dicarbene formation and olefinic insertion was attempted. However, what was observed was 1,3-dipolar addition of the bisdiazo compounds and strained olefinic systems such as norbornene and norbornadiene. Nuclear magnetic resonance spectroscopy indicates that the stereo-chemistry of the adducts formed lead to some large chemical shifts. Polymerization was also attempted between meta-bisdiazobenzoylbenzene and norbornadiene.

The Maximum Principle was applied to determine the types of temperature variations that minimize and maximize the breadth of the molecular weight distribution (MWD) for chain addition polymerizations in batch reactors. It was found that the variations which minimize the breadth of the MWD keep the instantaneous number average chain length constant. The variations which maximize the breadth of the MWD are step changes in temperature resulting in bimodal distributions. Numerical and experimental examples of such variations are presented. MWDs with minimum and maximum breadths are compared to those that might be formed by temperature variations in real reactors. Under most conditions, temperature variations appear to have a much greater effect on MWD than residence time distributions and micromixing.

in a search for metallocene derivatives as additives, monomers, and polymers with high UV radiation resistance, the preparation of osmocene and ruthenocene analogs of o-hydroxybenzophenone was investigated, and a study was made of the conversion of functional cyclopentadienes to ferrocenes. New compounds prepared included ortho hydroxybenzoylosmocene, orthohydroxybenzoylru thenocene, orthomethoxybenzoylruthenocene, 1,1' bis(beta,beta-diethoxyethyl)- ferrocene, 1,1'-bis (beta-hydroxy-ethyl)-ferro cene, (C2H5O)2- CHCH2C5H4)3HFe, (HOCH2CH2C5H4)4H2Fe, dimethyl and diethyl 1,1'-ferrocene-dicarbamates, poly(1,1' ferrocenedimethyl 1,1'-ferrocenedicarbamate), Os2OCl8, 6-carbethoxy-3,4- dihydrofulvene, and cyclopentadienes containing beta-carbethoxyethyl, cyanomethyl, beta,beta-diethoxyethyl, and beta hydroxyethyl groups. Isomeric bis- and tris (trimethylene)ferrocenes were prepared and acetylated. The acetyl products were converted to the corresponding ferrocene-propionic acids, which on cyclization were shown to give homoannularke tonic products, as well as the expected hetero annular compounds.

Synthesis of a variety of fluorine-containing compounds was studied. A convenient synthesis of perfluoroallyl halides was developed. Lewis acid catalyzed addition of haloalkanes to olefins resulted in new fluoroolefins. A series of fluorine monomers were prepared for polymerization studies. A number of partially fluorinated norbornadienes were prepared by the reaction of cyclopentadiene with haloolefins and subsequent dehalogenation. Several new fluorinated nitroso monomers were prepared. A series of compounds of the general structure (CH3)3SiCF=CFR were synthesized utilizing organolithium reagents. Alcoholysis of these compounds provides a convenient route to 1,2- difluoroolefins. Several other unsaturated fluoroorganometallic compounds were prepared and their reactions studied. It was found that they could be reacted with carbonyl compounds to produce alcohols which on dehydration gave fluorinated dienes.

Study of the phenomenon of flow decay, begun on earlier programs, was continued with a change to MSC PPD-2A propellant (N2O4 + 0.6 percent NO). Flow decay occurs with this propellant, even when dry (less than 0.1-percent water equivalent), as a result of deposits of the solid corrosion product, NOFe(NO3)4. It was found that the presence of excess water in amounts up to the general use limit of 0.2 percent changed the characteristics of the deposits formed when nitrogen tetroxide is heated, then cooled prior to or during flow. Instead of the crystalline solid (NOFe(NO3)4) which is deposited from dry propellant, gelatinous or viscous liquid phases are formed in wet propellant. The appearance of these deposits is governed by an equilibrium solubility limit similar to that observed for the solid deposits in dry propellant. The gelatinous or viscous liquid deposits were not observed to adhere to and plug valves and orifices, as does NOFe(NO3)4, but they did clog filters. Chemical additives previously shown to be effective in dissolving and eliminating NOFe(NO3)4 were not effective against the deposits obtained from wet propellant. Traces of aluminum and titanium were detected in flow decay deposits obtained from flow systems with aluminum and titanium tanks.

A simple synthesis of new electronegatively substituted bicyclobutane monomers has been worked out. It involves a 2+2 cycloaddition of tri(electronegatively substituted) ethylenes with dimethylaminoethylenes, followed by conversion to the quaternary ammonium salt and cross-ring elimination effected by base. A new copolymer synthesis involving the copolymerization of tri(electronegatively substituted) ethylenes with electron-rich vinyl monomers has been established under free radical polymerization conditions. A second new copolymer synthesis, involving the copolymerization of tri(electronegatively substituted) ethylenes with mono(electronegatively substituted) bicyclobutane monomers has been devised. The synthesis of an intermediate for a new type of monomer, the 2-oxabicyclobutanes, has been accomplished. It involves chlorination of 2-cyanooxacyclobutanes, followed by dehydrohalogenation to give the bicyclic compound.

The monomeric reactants approach was used to fabricate addition-type polyimide/graphite fiber composites with improved mechanical properties and thermal stability characteristics over those of composites derived from addition-type amide acid prepolymers. A screening study of 24 different monomer combinations was performed. The results of a more extensive investigation of a selected number of monomer combinations showed that the combination providing the best thermomechanical properties was 5-norbornene -2,3 -dicarboxylic acid monomethyl ester/4, 4'-methylenedianiline /3, 3'4, 4' -benzophenonetetracarboxylic acid dimethyl ester at a molar ratio of 2/3.09/2.09.

The reaction rate data of the hydroxyl radical in aqueous solution are compiled and evaluated in this critical review. The values are reported in a series of tables covering addition, hydrogen abstraction, inorganic electron transfer and radical reactions. Rate constants for the hydroxyl radical with biological molecules are included. In addition, the rate constant data for the oxide radical ion are given. Physical properties are listed and the experimental methods employed in OH radical chemistry are reviewed. An analysis involving rate constant data comparisons is made.

An evaluation of two high-temperature addition-cured adhesives. These were (1) NITRILE SUBSTITUTED POLYPHENYL ETHERS CURED WITH TERPHTHALONITRILE N, N-dioxide (TPNO) AND (2) acetylene termin-ated polyimide (HR600) cured thermally. The thermally cured acetylene terminated polyimide proved to be superior to the TPNO cured cyano substituted polyphenylene oxide. Lap-shear strengths of 6A14V titanium bonded with HR600 adhesive exceeded 3000 psi at ambient temperature on powdered aluminum-filled specimens reinforced with heat cleaned 112 glass fabric and 2800 psi at ambient temperature, 2600 psi at 450F and 2100 psi at 500F on unfilled specimens bonded with 70 percent HR600 prepreg on 112 heat cleaned glass fabric. Weld-bonding of titanium specimens using aluminum powder filled HR600 adhesive proved to be successful and showed superior fatigue resistance over spot-welded specimens.

Supersedes AD-028 371.

Two highly promising approaches to yield autoclavable addition-type polyimides were identified and evaluated in the program. Conditions were established for autoclave preparation of Hercules HMS graphite fiber reinforced composites in the temperature range of 473 deg K (390 deg F) to 505 deg K (450 deg F) under an applied pressure of 0.7 MN/sq m (100 psi) for time durations up to four hours. Upon oven postcure in air at 589 deg K (600 deg K), composite samples demonstrated high mechanical property retention at 561 deg K (550 deg F) after isothermal aging in air for 1000 hours. Promise was shown for shorter term mechanical property retention at 589 deg K upon exposure in air at this temperature. jg p2

Three resin systems based on the addition reaction of the nitrile oxide group with nitrile and acetylene groups were investigated as to their suitability for impregnating fabric reinforcements and subsequently molding composite structures using little applied pressure. These resins were nitrile-terminated polyimides, acetylene terminated polyimides and nitrile substituted phenylene oxide oligomers. Procedures for their preparation are presented as well as the method of A-staging with terephthalonitrile N,N'-dioxide to yield resins suitable for the fabrication of glass cloth reinforced laminates using little applied pressure or vacuum bag molding techniques. Laminates prepared from these resins are stable in air up to at least 500 F with fairly good retention of thermal mechanical properties. These resins were amenable to vacuum bag molding techniques using molding temperatures in the range of 475-550 F and molding pressure of 14.7 psi. Thermal mechanical properties were measured for these laminates and are presented. (Author-PL)

N-Phenyl-substituted quinoxaline ladder polymers were synthesized by the condensation polymerization of 2,3,7,8-tetraphenoxy-1,4,6,9-tetraazaanthracene and 2,3,7,8-tetraanilino-1,4,6,9-tetraazaanthracene. It had been postulated that related quinoxaline ladder polymers reached a rigid, unreactive state at low molecular weights partly because of intermolecular hydrogen bonding, and the phenyl substituents were expected to prevent these excessive intermolecular forces. However, these polymers also failed to polymerize to sufficiently high molecular weights to produce a cohesive laminating resin. A method of preparing similar but highly crosslinked resins was investigated. This method consisted of condensing tetraphenoxy-tetraazaanthracene with benzidine to replace some of the phenoxyl substituents and to form a linear or branched prepolymer, followed by displacing the remaining phenoxyl groups with aniline and condensing the resulting prepolymer with more tetraphenoxytetraazaanthracene to form ladder segments in the final cure. A glass fabric-reinforced laminate was molded from this polymer with a flexural strength of 11,400 psi. The prepolymer derived from tetraphenoxytetraazaanthracene and benzidine was also cured directly by heating, although the product was expected to have only very short ladder segments in its highly crosslinked structure. A laminate fabricated from this resin had a flexural strength of 27,200 psi., See also AD-864 104.

This paper is a study of stable compounds having bivalent carbon atoms of the carbon monoxide type, esters of fulminic acid, and isonitriles. The electrophilic properties of carbenes are discussed. Of particular interest are the Passerini, Ugi, alpha-addition and complex-formation reactions of these compounds, which are discussed at some length. (Author), Trans. of Vsesoyuznoe Khimicheskoe Obshchestvo. Zhurnal (USSR) v12 p65-76 1967.

The synthesis of a new tetrazole double dipole, 2,2'-diphenyl-5,5'-m-phenyleneditetrazole, has been accomplished. The reaction of this bistetrazole with phenylacetylene yielded the model compound 1,1',5,5'-tetraphenyl-3,3'-m-phenylenedipyrazole. The attempted polymerization reaction of 2,2'-diphenyl-5,5'-p-phenyleneditetrazole with terephthalonitrile in either acetic acid or nitrobenzene has been carried out, but no polymer was obtained. A monomer balance study was carried out on the polymerization reaction of 2,2'-diphenyl-5,5'-p-phenyleneditetrazole with tetrafluoroterephthalonitrile for the formation of poly(1,1'-diphenyl-3,3'-p-phenylene-5,5'-(tetrafluoro-p-phenylene) -ditriazole). (Author)

A detailed investigation of the reaction of a series of pyridines with titanium tetrafluoride has been carried out with high-resolution fluorine-19 nuclear magnetic resonance spectroscopy. Instead of the formation of only simple diadducts a mixture of products is found in the solvent acetonitrile. The main species are TiF4 - 2D, TiF3 - 3D(+) and TiF5 - D(-). An extensive series of TiF5 - d(-) complex ions is studied by (19)F nmr. Linear correlations of the chemical shifts of the fluorines in TiF4 - 2D and TiF5 - D(-) complexes are found with the pKa values of the substituted pyridines. Some complexes of TiF4 with bidentate ligands are reported as well as some products with sulfur containing ligands. Fluorine-19 nmr data are also given for some GeF4 - 2D adducts where D represents some substituted pyridine 1-oxides. Geometrical isomers were found with GeF4 - 2D compounds and both first and second order nmr spectra were measured. (Modified author abstract)

The identification of aromatic heptaene antibiotics of the candicidin group (trichomycin, levorin, candicidin) has been hampered due to the complete coincidence of the usual physicochemical parameters for these antibiotics. They can be distinguished only by extremely complex analysis methods - counterflow distribution, IR and NMR spectra. In seeking a fairly simple method of estabilishing the authenticity of these antibiotics for mass analysis, the authors noticed that all of them form intensively blue solutions in concentrated sulfuric acid. This is evidently explained by their protonation along the haptaene chain with the formation of the carbonic ion II with a positive charge. Preliminary experiments showed that the protonation reaction is suitable for identification of heptaene antibiotics and apparently is characteristic for the majority of polyene antibiotics., Edited trans. of Nauchno-Issledovatelskii Institut Antibiotikov. Konferentsii Molodykh Uchenykh Leningradskogo Instituta Antibiotikov 2-Y, Leningrad, Jun 64. Materialy, n.p., n.d., p12-13, by Dean F. W. Koolbeck.

The Russian patent describes a method of obtaining iodinated perfluorocarbons from crystalline iodine and liquid unsaturated perfluorocarbons. It is distinguished by the fact that in order to increase the effectiveness of the process, the reaction mixture is brought to the pseudoboiling state or to a state of intensive agitation and is irradiated with ionizing radiation. (Author), Edited trans. of Patent (USSR) 173 213 2p 1970, by Dean Koolbeck.

A new synthesis of 1,2-dicarbaclosododecaborane is described which involves the reaction of acetylene with B10H12L2 compounds in the solid state. This simplified laboratory procedure provides pure o-carborane in one step as a sublimate from the reaction mixture. (Author)

Competitive interaction of O(singlet D) atoms, formed by photolysis of N2O at 2139 A, with neopentane and a number of other gases has been studied at room temperature. Formation of the ground-state oxygen atoms, O(triplet P), in these experiments was followed by measuring the characteristic products of their addition to butene-1. It was found that under the conditions employed SF6 and He did not interact with O(singlet D), H2, CH4, and neopentane reacted to form products but did not deactivate O(singlet D), while N2, Xe, CO and CO2 deactivated O(singlet D) to O(triplet P). The rates of these processes, relative to the rate of reaction of O(singlet D) with neopentane, k5/k2, were determined from the decrease in the yields of neopentanol when another gas was added. Where a comparison is possible, the trend is in good agreement with the previous results from this laboratory obtained in very different systems. Carbon monoxide does not show an exalted reactivity toward O(singlet D) atoms and, moveover, does not, under the conditions employed, chemically react with them to form CO2 but deactivates them to the ground state, O(triplet P). (Author)

The radiation-induced dimerization of 1,3-cyclohexadiene occurred by two simultaneous mechanisms: mechanism 1 produced mainly the endo and exo Diels-Alder products of 1,4,1',2' addition; mechanism 2 produced mainly the cis-anti-cis and cis-syn-cis isomeric products of 1,2,1',2' addition. Both mechanisms were sensitized by the aprotic solvents benzene, n-hexane, cyclohexane, and di-n-propyl ether, and were inhibited by the protic solvent ethanol. Mechanism 1 involved a cationic chain reaction in benzene, and probably also in the other aprotic solvents. In all the aprotic solvents the yield of the Diels-Alder products went through a maximum as the 1,3-cyclohexadiene (CHD) concentration was increased. There was no evidence of a chain in mechanism 2 and the yields of the corresponding dimers were relatively small. It appears that triplet-state CHD molecules were the immediate precursors of the dimers from mechanism 2, and that roughly half of the triplet CHD molecules resulted directly or indirectly from neutralization reactions. (Author)

Insertion reactions of some metal (B, Si, Ge, Sn(IV), Ti(IV), Zr(IV), and Hf(IV), amides with nitriles, diketene, crotonaldehyde, lambda-butyrolactone, and propylene sulphide are described along with their reactions with the protic species ethyleneimine, alkynes and pentafluorobenzene. Also discussed is the metathetical exchange reactions with boron trifluoride and with fluorcarbons and some seven co-ordinate manganese(III) complexes. Next a comprehensive summary of earlier work on (a) reactions of organo-sodium and -lithium reagents with unsaturated compounds, (b) insertion reactions of nitriles, and (c) reactions of organolithium reagents with metal carbonyls is presented; plus the results of investigations of (i) insertions of benzonitrile into lithium dimethylamide and bis(trimethylsilyl)amide, (ii) reactions of acetonitrile with the same amides, and (iii) reactions of lithium dimethylamide with some Group(VIA) metal carbonyls. The syntheses of new organometallic diazoalkanes along with their reactions: 1,3-cyclo-additions to some unsaturated substrates; 1,3-insertion reactions into the M-H bond of pi-C5H5(CO)3 M-H (M = Mo or W) so afford azo-compounds; and metal-carbon cleavage reactions. The work also provides an alternative synthesis of several such compounds and also of pi-cyclopentadienylmetal hydrides by way of a novel oxidative addition of sigma-cyclopentadienyl metallates or of cyclopentadiene to metal carbonyl residues. Mentioned are the novel dialkylamides of Ti(III).

The base-catalyzed condensation of 3-quinuclidinone with quinoline carboxaldehydes provides easy access to a large number of compounds which may be loosely described as desvinylquinine derivatives. Many such substances have been synthesized and submitted for antimalarial screening. Of particular interest are the quinolinemethanols obtained by acid-catalyzed hydration of the condensation products. The unique metal complexes of 2-(2'-quinolyl)methylene-3-quinuclidinone which were encountered during this work and progress on an attempt to synthesize the complete quinine skeleton are also described. (Author)

The absolute values of the second-order rate constants for the reactions of ozone with chloroethylenes and allyl chloride were determined in carbon tetrachloride solution at room temperature. The rate of ozone attack decreases strongly as the number of chlorine atoms in the olfefin molecules is increased. The large variation in the values of the rate constants for the chloroethylenes, from 1.01/mole/sec for C2Cl4 to 1200 1/mole/sec for C2H3Cl, is believed to be primarily due to a predominantly electrophilic role of ozone in its reactions with these olefins. A pronounced additional trend is shown by the three isomeric dichloroethylenes: trans-1,2-C2H2Cl2 is about 16 times more reactive than cis-1,2-C2H2Cl2, while 1,1-C2H2Cl2 is the least reactive of the three isomers. These trends are discussed in terms of the electronic and steric effects and are compared with the behavior of other 1,3 dipoles in their cycloadditions to olefins. Relative rates of ozonation of 1,3-C4H6 and styrene were determined by competition with 1-pentene. The two conjugated olefins do not show a strongly increased reactivity and in this respect differ from the behavior reported for some other 1,3-dipolar cycloadditions. (Author)

Further evidence for a fast reaction between triplet methylene and carbon monoxide (with the production of ketene) is reported.

Contents: Addition to the carbon-nitrogen double bond of fluorosulfuryl isocyanate, FSO2NCO; Derivatives of bis(trifluoromethyl) ketene which contain fluorosulfato, difluoroimino, and/or fluoroxy groups; Some chemistry of difluoraminocarbonyl fluoride, NF2CFO; The preparation of perfluorourea, (NF2)2CO, and difluoroaminocarbonyl chloride NF2C(O)Cl; New preparations for NF2OCF3 and NF2Cl; A simple method for the preparation of nitrosyl fluoride; The silver (II) fluoride-catalyzed formation of tris(trifluoromethyl)hydroxylamine, (CF3)2NOCF3., See also AD0640893. Sponsored in part by the DARPA.

The objective of the research was the characterization of carbonium ion and free radical intermediates in the bicyclo(3.1.0)hexyl system and carbene intermediates in the bicyclo(3.1.0)hexylidene system. Electrophilic additions of hydrogen chloride and the conjugate acid of methanol to bicyclo(3.1.0)hexene-2 demonstrate that the trishomocyclopropenyl carbonium ion is not a detectable product determining intermediate and that the addition reactions proceed via a 2-bicyclo(3.1.0)hexyl intermediate. Two bivalent intermediates were generated by sodium methoxide induced decomposition of the p-toluenesulfonylhydrozon es of bicyclo(3.1.0)hexanone and 2-bicyclo(3.1.0)hexanone. Free radical addition of methanethiol to bicyclo(3.1.0)hexene-2 yields thiomethoxybicyclohexanes and thiomethoxymethylcyclopentenes. Free radical chlorination, using t-butyl hypochlorite, and chloroformyllation, using oxalyl chloride, generate exclusively 2- and 3-bicyclo(3.1.0)hexyl radical intermediates, which behave in a completely analogous fashion to the thiomethoxy radicals generated in methanethiol addition. (Author)

This report describes further attempts to prepare the ClF6 anion. The use of large excesses (up to ClF5:CsF of 120:1) or the use of activated CsF did not result in products containing the desired anion. Conflicting reports have appeared in the literature concerning the existence of a NOF-ClF5 adduct formed at -78 degrees. An investigation of this system showed that, while mixtures of NOF and ClF5 show a negative deviation from Raoult's Law, no solid product is formed. (Author)

A process for the preparation of an inert terpolymer of allyl acrylate -acrylic acid - methyl acrylate, which on addition of tetrafluorohydrazine produces a polymer equivalent to NFPA prepolymer, has been developed. Thus, the handling of the hazardous intermediates in the production of NFPA prepolymer can be avoided. The continuous-process reactor for the preparation of the geminal bis(difluoramino) adduct of trifluoroacetoxy acetone, the precursor of geminal NFPA, has been modified. The new reactor provided yields of 88% of the desired geminal bis(difluoramine). A successful synthesis of all geminal bis(difloramine) plasticizers with an NF content of 60% has been worked out. A polyhydroxy compound, (ethylene glycol, glycerol, or pentaerythritol) is converted to the poly-propargyl ether. Hydrolysis of the acetylene functions provides a poly-ketone that can be difluoraminated smoothly with difluoramine-sulfuric acid. The synthesis of a nylon-6 type monomer, 5,5-bis (difluoramino)-2-azacycloheptanone, has been completed. Degradation studies on related caprolactams are also reported.

The synthesis of N-(3-pyridyl)-sydnone has been effected by the dehydration of N-nitroso-N-(3-pyridyl)-glycine. The synthesis of 3-phenylsydnone-4-carboxylic acid has been carried out by lithiation and carbonation of 3-phenylsydnone and this acid has been converted to the acid chloride. The disydnone 4,4'-bis(3-phenylsydnonyl)sulfone has been prepared from the lithium salt of 3-phenylsydnone. The 1,1'-diphenyl-3, 3'-m-phenylene-delta 2-pyrazoline has been synthesized. The dinitrilimine precursor, 5,5'-p-phenylene-ditetrazole, has been synthesized by the reaction of terephthalonitrile with sodium azide. The polymerization of p-phenylene-3,3'-disydnone with m-divinylbenzene to yield poly(1,1'-p-phenylene-3,3'-m-phenylene-di-delta 2-pyrazoline) has been effected. A series of polymerizations with terephthaloylphenylhydrazide chloride in which the monomer balance was varied has been carried out. The polymerization of 2,2'-diphenyl-5,5'-p-phenyleneditetrazole with 4,4'-dicyanobiphenyl has afforded poly(1,1'-diphenyl-3,3' -p-phenylene-5,5'-p-biphenylene-ditriazole). (Author)

The chemistry of peroxy radicals is reviewed. Discussed is radical displacement, oxygen atom transfer, radical reactions, and unimolecular decomposition.

The research reported in AFML-TR-70-39 Part 3, March 1972, was continued. Five new dipolarophilic-terminated oligomeric polyimides were prepared and reacted with the dipole, BDNO, to give some polymers with TGA inflections in air in the 500 C region. Styrene-, allyl- and phenol-terminated oligomeric polyimides were prepared and epoxidized. In all cases, the epoxide softening points increased and solubility decreased relative to their precursors. The TGA thermal stabilities of the cured epoxides in air show breaks in the 240-390 C region and inflections in the 300-570 C regions, depending on the structures and methods of cures. A number of amine- and anhydride-terminated oligomers were prepared and cured by epoxides to products having TGA breaks in air in the 240-300 C regions, and inflections in the 560-600 C regions. The curing of nitrile-terminated oligomers by copper halide catalysts did not yield promising results. The coreaction of dioxane-soluble amine-terminated oligomeric polyimides with dioxane-soluble anhydride-terminated oligomers appears to offer promising, practical systems having good processability which yield highly thermally stable polyimides as final products. (Author)

A brief review is given of the reaction of ozone with akenens, and the reaction mechanism of ozonolysis.

The preparation and characterization of Tropone dimethylketal is described. Cyclopropenone dimethylketal was obtained by pyrolytic cleavage of the Diels-Alder adduct resulting from the addition of dimethyl acetylenedicarboxylate to tropone dimethylketal. (Author)

Addition compounds of HfCl4 and ZrCl4 with eight organic ligands were prepared and analyzed. Infrared spectral and thermal decomposition measurements demonstrated the similarity of properties between addition compounds of these two metal tetrahalides. (Author)

It was previously reported (J. Am. Chem. Soc. v89 p2557 1967) that the gas-phase interaction between tetraborane (10) and acetylene, takes place explosively at 100C to give volatile closo-carboranes, and at 25 to 50C proceeds slowly to form derivatives of the nido-carborane C3B3H7 in small yields. In an effort to better understand the general nature of the slow reactions, especially the formation of carborane cage systems, a detailed examination was made of the gas-phase reactions of B4H10 and B5H11 with several small alkynes. Since both B4H10 and B5H11 react with alkynes at room temperature the results of these studies, added to available data on other borane-alkyne systems, give some new indications of the role of borane structural features in reactions of this type. The extreme sensitivity of gas chromatography, coupled with mass spectroscopic, infrared, and nmr techniques, permitted the isolation and structural characterization of virtually all volatile products.