Application of liquid-crystal thermometry to drop temperature measurements

A technique has been developed that enables remote sensing of the temperatures of liquid drops in a medium of an immiscible, transparent liquid with the aid of dispersing microcapsules of thermochromic liquid crystal in each drop under illumination by either a planar floodlight or a light sheet which cuts the drop at a meridian. Based on appropriate hue-temperature calibrations made with an isothermal, stationary drop/medium system, one can analyze spatial and time variations of temperature within drops in motion under transient convective heating (or cooling) from the medium.List of Symbols B tristimulus blue component - D drop diameter - G tristimulus green component - H hue angle - h ₀ constant term in the expression for H - H _m mean value of H over drop surface - h vertical coordinate fixed onto test column - R tristimulus red component - Re drop Reynolds number, UD/v _c - r, g, b chromaticity coordinates - r drop radius - s penetration depth of light into drop - T temperature - T _d instantaneous drop temperature - T _d0 initial drop temperature - T _c continuous-phase temperature - U velocity of rise of drop - z vertical coordinate laid on drop - v _c kinematic viscosity of continuous phase - angle of lighting measured from camera axis - _s local view angle (azimuth) - polar angle     

Cluster Formation of 1-Butanol–Water Mixture Leading to Phase Separation

Microscopic structures of 1-butanol (1-BuOH)–water mixtures in the presence and absence of salts are studied through the mass spectrometric analysis of clusters generated from the fragmentation of liquid droplets. The analysis of cluster structures provides information on the phase separation of 1-BuOH–water mixtures from the microscopic viewpoint. In a saturated solution of 1-BuOH in water, 1-BuOH exists as hydrated 1-BuOH clusters and self-associated 1-BuOH clusters. With further addition of 1-BuOH, a 1-BuOH rich phase is generated. When the salt (LiCl, NaCl, MgCl₂, etc.) coexists in the 1-BuOH–water mixtures, the cation is preferentially solvated by the 1-BuOH to form M ⁺(1-BuOH) _m or M ²⁺(1-BuOH) _m clusters: M ⁺ = Li⁺, Na⁺, Mg²⁺ = Mg²⁺, etc., m = 1, 2, 3, ... Since the formation of M ⁺(1-BuOH) _m corresponds to an increase of the self-associated 1-BuOH clusters in water, the presence of the salt induces the phase separation at lower 1-BuOH concentrations.     

Effect of alkyl substitueras in hydrophobic 8-quinolinol on the extraction of gallium(III) and applications to the separation of gallium(III) from aluminum(III)

The extraction of gallium(III) with newly prepared 5-alkyloxymethyl-8-quinolinol derivatives with alkyl substituent at the 2-position in 8-quinolinol moiety has been studied. The Ga(III)-5-octyloxymethyl-8-quinolinol (HO(8)Q), Ga(III)-2-methyl-5-octyloxymethyl-8-quinolinol (HMO(8)Q), Ga(III)-2-methyl-5-hexyloxymethyl-8-quinolinol (HM-O(6)Q), and Ga(HI)-2-n-butyl-5-hexyloxymethyl-8-quinolinol (HNBO(6)Q) complexes extracted in heptane from a perchloric acid medium were Ga(O(8)Q)(3), Ga(OH)(H(2)O)(MO(8)Q)(2), Ga(OH)(H(2)O)(MO(6)Q)(2) and Ga(OH)H(2)O)(NBO(6)Q)(2), respectively. The 2-tert-butyl-5-hexyloxymethyl-8-quinolinol did not exhibit any reactivity toward gallium(III). The extraction constants for Ga(O(8)Q)(3) (K(ex) = [Ga(O(8)Q)(3)](org) [H(+)](3)/[Ga(3+)][HO(8)Q](org)(3)), Ga(OH)(H(2)O)(MO(8)Q)(2) (K(ex) = [Ga(OH) (H(2)O)(MO(8)Q)(2)](org) [H(+)](3)/[Ga(3+)][HMO(8)Q](org)(2)), Ga(OH)(H(2)O)(2)(MO(6)Q)(2) and Ga(OH)(H(2)O)(NBO(6)Q)(2), which were extracted in heptane from an acidic solution, are 10(3.21 +/- 0.12), 10(-4.24 +/- 0.16), 10(-3.84 +/- 0.16) and 10(-4.07 +/- 0.07), respectively at I = 0.1 M and 25 degrees C. HNBO(6)Q exhibited very high selectivity toward gallium(III) in the presence of aluminum(III). Even in the presence of a 100 fold excess of aluminum(III) to gallium(III) (1.43 x 10(-5) M), gallium(III) was completely extracted and the distribution ratio of aluminum(III) was found to be less than 2.0 x 10(-3).     

Crystal structure of 1,3-diphenyladamantane and trans-1,4-diphenylcyclohexane: torsion angles about C-Ph bonds in α,ω-diphenyl(alicyclic hydrocarbon)

The orientation of the two phenyl rings in α,ω-diphenylalkanes with rigid carbon skeletons is investigated through characterization of the crystal and molecular structures of 1,3-diphenyladamantane (1) and trans-1,4-diphenylcyclohexane (2). The two phenyl rings in 1 have different conformations about the C-Ph bonds, with torsion angles between the phenyl ring and the C1-C2-C3 plane of 0.65 and 71.7°. A hydrogen atom at the meta-position of one of the phenyl rings contact intermolecularly with a tertiary hydrogen atom at C5 of adamantane within the sum of van der Waals radii. Due to the helical conformation, the short CH?HC contacts (2.231 Å) construct supramolecular triple helical strands. In contrast to 1, the phenyl rings in 2 have identical configurations, with equatorial position and bisected conformation as expected from density functional calculations. The molecular packing of 2 exhibits a herringbone pattern of (aromatic)C-H?π contacts.     

Synthesis and ligand-based mixed valency of cis- and trans-Cr(III)(X(4)SQ)(X(4)Cat)(L)(n) (X = Cl and Br,n = 1 or 2) complexes: effects of solvent media on intramolecular charge distribution and ligand dissociation of Cr(III)(X(4)SQ)(3)

The treatment of Cr(III)(X(4)SQ)(3) (SQ = o-semiquinonate; X = Cl and Br) with acetonitrile affords trans-Cr(III)(X(4)SQ)(X(4)Cat)(CH(3)CN)(2) (X = Cl (1) and Br (2)). In the presence of 2,2'-bipyridine (bpy) or 3,4,7,8-tetramethyl-1,10-phenanthrene (tmphen), the reaction affords Cr(III)(X(4)SQ)(X(4)Cat)(bpy).nCH(3)CN (X = Cl, n = 1 (3); X = Br, n = 0.5 (4)) or Cr(III)(X(4)SQ)(X(4)Cat)(tmphen) (X = Cl (5) and Br (6)), respectively. All of the complexes show a ligand-based mixed-valence (LBMV) state with SQ and Cat ligands. The LBMV state was confirmed by the presence of the interligand intervalence charge-transfer band. Spectroscopic studies in several solvent media demonstrate that the ligand dissociation included in the conversion of Cr(III)(X(4)SQ)(3) to 1-6 occurs only in solvents with relatively high polarity. On the basis of these results, the effects of solvent media were examined and an equilibrium, Cr(III)(X(4)SQ)(3) <--> Cr(III)(X(4)BQ)(X(4)SQ)(X(4)Cat) (BQ = o-benzoquinone), is proposed by assuming an interligand electron transfer induced by solvent polarity.     

Synthesis and photochemical properties of solar energy storage-exchange polymers containing pendant norbornadiene moieties

New photoresponsive polymers 1–4 containing pendant norbornadiene (NBD) moieties with N,N-disubstituted amide groups were synthesized with 97, 98, 92, and 94% conversions by the substitution reaction of poly (p-chloromethyl) styrene] with potassium salts of 3piperidyloxo-2,5-NBD-2-carboxylic acid, 3-(NN-dipropylcarbamoyl) -2,5-NBD-2-carboxylic acid, 3-(N-methyl-N-phenylcarbamoyl)-2,5-NBD-2-carboxylic acid, and 3-(N,N-dipheylcarbmoyl)-2,5-NBD-2-carboxylic acid, respectively, using tetrabutylammonium bromide as a phase transfer catalyst for all. Polymers 1–4 with N,N-disubstituted amide groups on the NBD moieties were sensitized by adding appropriate photosensitizers such as Michler's ketone and 4- (N,N-dimethylamino) benzophenone in the film state, although the reactivities of the polymers without photosensitizer were lower than that of our previously reported polymer 5 containing pendant 3- (N-phenylcarbamoyl) -2,5-NBD-2-carboxylate moiety. It was also found that the photo-irradiated retaining polymers 1–4 containing the corresponding QC moieties can be stored about 80–86 kJ/mol of their thermal energy. © 1994 John Wiley & Sons, Inc.     

Fast ring opening of unstable mesoionic 1,3-dioxolylium-4-olates to acyloxyketenes: formation of [2+2] cycloadducts of acyloxyketene with several ketenophiles

Fast ring opening of mesoionic 1,3-dioxolylium-4-olate 5, generated by Rh₂(OAc)₄-catalyzed decomposition of a phenyldiazoacetic anhydride 6, to an acyloxyketene 10 was demonstrated by trapping the ketene 10. Rh₂(OAc)₄-catalyzed decomposition of p-nitrophenyldiazoacetic p-chlorobenzoic anhydride 6a in the presence of ketenophiles such as dihydrofuran, carbodiimides, and imines did not give 1,3-dipolar cycloadducts with the 1,3-dioxolylium-4-olates 5a, but their [2+2]-cycloadducts with the acyloxyketene 10a. PM3 calculation of heats of formation of a 1,3-dioxolylium-4-olate 5 and an acyloxyketene 10 indicates that the acyloxyketene 10 is 9 kcal/mol more stable than the 1,3-dioxolylium-4-olates 5.     

Application of slurry nebulization to trace elemental analysis of some biological samples by inductively coupled plasma mass spectrometry

Summary The application of slurry nebulization/inductively coupled plasma mass spectrometry (ICP-MS) to trace elemental analysis of biological samples has been investigated. Three standard samples of the National Institute of Standards and Technology (NIST) were dispersed in 1% aqueous Triton X-100 solution by grinding with a planetary micronizing mill. The resulting slurries were nebulized into an ICP without any additional treatments. The 1% (m/v) slurry of the NIST bovine liver showed no significant influence on cone blockage and signal suppression/enhancement. Detection limit, precision and accuracy were discussed for the determination of 24 elements of interest in bovine liver, rice flour and pine needles. Detection limits ranged from 0.0001 g g^–1 for U to 0.52 g g^–1 for Zn at the effective integrating time of 10 s. For high mass elements, low blank values were obtained, yielding excellent limits (<0.01 g g^–1). Acceptable accuracy and precision were obtained for most of the elements in the NIST bovine liver and rice flour, even for the volatile elements, such as As, Se and Br. However, relatively poor accuracy was obtained for the analysis of pine needles.     

Imidazole‐Aided Native Chemical Ligation: Imidazole as a One‐Pot Desulfurization‐Amenable Non‐Thiol‐Type Alternative to 4‐Mercaptophenylacetic Acid

Various bioactive proteins have been synthesized by native chemical ligation (NCL) and its combination with subsequent desulfurization (e.g., conversion from Cys to Ala). In NCL, excess 4‐mercaptophenylacetic acid (MPAA) is generally added to facilitate the reaction. However, co‐elution of MPAA with the ligation product during preparative high‐performance liquid chromatography sometimes reduces its usefulness. In addition, contamination of MPAA disturbs subsequent desulfurization. Here, we report for the first time that imidazole can be adopted as an alternative to MPAA in NCL using a peptide‐alkylthioester. The efficiency of the imidazole‐aided NCL (Im‐NCL) is similar to that of traditional MPAA‐aided NCL. As model cases, we successfully synthesized adiponectin(19‐107) and [Ser(PO₃H₂)⁶⁵]‐ubiquitin using Im‐NCL with a one‐pot desulfurization.