Carboxylic acid

Abstract: 4.3. Reaction Mechanism 2373 4.4. Asymmetric Synthesis 2374 4.5. Outlook 2374 5. Alternating Polymerization of Oxiranes and CO2 2374 5.1. Reaction Outlines 2374 5.2. Catalyst 2376 5.3. Asymmetric Polymerization 2377 5.4. Immobilized Catalysts 2377 6. Synthesis of Urea and Urethane Derivatives 2378 7. Synthesis of Carboxylic Acid 2379 8. Synthesis of Esters and Lactones 2380 9. Synthesis of Isocyanates 2382 10. Hydrogenation and Hydroformylation, and Alcohol Homologation 2382

Abstract: Deep Eutectic Solvents (DES) can be formed between a variety of quaternary ammonium salts and carboxylic acids. The physical properties are significantly affected by the structure of the carboxylic acid but the phase behavior of the mixtures can be simply modeled by taking account of the mole fraction of carboxylic acid in the mixture. The physical properties such as viscosity, conductivity, and surface tension of these DES are similar to ambient temperature ionic liquids and insight into the cause of these properties is gained using hole-theory. It is shown that the conductivity and viscosity of these liquids is controlled by ion mobility and the availability of voids of suitable dimensions, and this is consistent with the fluidity of other ionic liquids and molten salts. The DES are also shown to be good solvents for metal oxides, which could have potential application for metal extraction.

Abstract: In spite of its physiological importance acetylcholine has been determinable chemically only after isolation by time-consuming procedures. Of necessity workers in this field have resorted to pharmacological bioassays whose specificity seems open to doubt. The finding that choline is readily acetylated by the action of a coenzyme-linked enzyme system in which adenosine triphosphate serves as an energy source (1) lends added interest to the development of adequate analytical procedures for acetylcholine. This communication concerns certain properties of the interaction of scetylcholine with hydroxylamine, and the means of using this reaction, RCOOR’ + HzNOH ---f RCONHOH + R’OH, for the quantitative determination of acetylcholine. Feigl, Anger, and Frehden (2) have described the use of hydroxylamine as a spot test reagent (cf. also (3)). Lipmann and Tuttle (4) have based a specific quantitative method for the acyl phosphates on their ability to react with hydroxylamine in water at pH 6. Hill (5, 6) has used the reaction of est,ers with hydroxylamine at alkaline pH in anhydrous solvents to determine long chain fatty acid esters (cf. also (7)). The present method, which is designed for use with short chain 0-acyl derivatives, is based on the finding that hydroxylamine at an alkaline pH in water rapidly converts acetylcholine stoichiometrically to hydroxamic acid throughout a wide range of ester concentration. The specificity of the reaction as between esters and products of t.heir hydrolysis and its rapidity and technical simplicity have afforded an analytical method which is adaptable to widely different conditions. Hydroxylamine has been employed a,s a trapping reagent for acyl anhydrides in mixed enzyme systems by Lipmann and Tuttle (8) and others (9-11). Chantrenne (12) has shown that hydroxylamine at pH 7.1 also traps carboxylic acid esters. Experiments reported below evaluate the

Abstract: The organization of cationic or anionic organic and inorganic molecular species to produce three-dimensional periodic biphase arrays is described. The approach uses cooperative nucleation of molecular inorganic solution species with surfactant molecules and their assembly a t low temperatures into liquid-crystal-like arrays. The organic/inorganic interface chemistry makes use of four synthesis routes with @+I-), @-I+), (S+X-I+), and (S-M+I-) direct and mediated combinations of surfactant (cationic S+, anionic S-) and soluble inorganic (cationic I+, anionic I-) molecular species. The concepts can be widely applied to generate inorganic oxide, phosphate or sulfide framework compositions. Distinct lamellar, cubic silica mesophases were synthesized in a concentrated acidic medium (S+X-I+), with the hexagonal and the cubic phases showing good thermal stability. For the hexagonal mesostructured silica materials high BET surface areas (>lo00 m2/g) are found. Hexagonal tungsten(V1) oxide materials were prepared in the presence of quaternary ammonium surfactants in the pH range 4-8. Cubic (Iu3d) and hexagonal antimony(V) oxides were obtained by acidifying (pH = 6-7) homogeneous solutions of soluble Sb(V) anions and quaternary ammonium surfactants a t room temperature @+I-). Using anionic surfactants, hexagonal and lamellar lead oxide mesostructures were found (S-I+). Crystalline zinc phosphate lamellar phases were obtained a t low synthesis temperatures (4 \"C) and lamellar sulfide phases could be also readily generated a t room temperature. The synthesis procedure presented is relevant to the coorganization of organic and inorganic phases in biomineralization processes, and some of the biomimetic implications are discussed.

Abstract: In the present study, we report the systematic investigation of the effect of chemical oxidation on the structure of single-walled carbon nanotubes (SWNTs) by using different oxidants. The oxidation procedure was characterized by using infrared spectroscopy and transmission electron microscopy (TEM). The SWNTs were produced by chemical vapor deposition (CVD) and oxidized with three kinds of oxidants: (1) nitric acid (2.6 M), (2) a mixture of concentrated sulfuric acid (98 wt %) and concentrated nitric acid (16 M) (v/v = 3/1) and (3) KMnO4. The results reveal that the different functional groups can be introduced when the SWNTs are treated with different oxidants. Refluxing in dilute nitric acid can be considered as a mild oxidation for SWNTs, introducing the carboxylic acid groups only at those initial defects that already exist. The abundance of the carboxylic acid groups generated with this oxidant remained constant along with the treating time. In contrast, sonication of SWNTs in H2SO4/HNO3 increased ...