Formation of amino acids by the photochemical method using various carbon-containing substances in presence of nickel as catalyst

Summary In the course of artificial irradiation of sterile aqueous solutions of various organic compounds with a 1000-W electric lamp for 1200 hours in presence of nickel chloride as catalyst, various amino acids, whose nature depends on the nature of the carbon-containing substances, are formed in the solution.     

A note on demand functions with uncertainty

Demand functions with “additive” and “multiplicative” uncertainty can fail to satisfy the “Slutsky symmetry” conditions required for demand to be based on utility maximization. This makes welfare analysis infeasible, which is important in many applications. Additive uncertainty can also generate negative demand realizations, and this can create non-trivial analytical problems.     

Micellization of sodium dodecyl sulfate and polyoxyethylene dodecyl ethers in solution

The effect of polyoxyethylene type nonionic surfactants (C₁₂E _n n = 3, 4, 5, 6, 7 and 8) on the aqueous solution of sodium dodecyl sulfate (SDS) in absence and presence of NaCl was examined using small-angle neutron scattering (SANS), dynamic light scattering (DLS), and viscosity measurements. Upon addition of C₁₂E _n , micellar size of SDS was found to increase significantly, and such micellar elongation was further enhanced in the presence of NaCl. Micellar growth is most significant in presence of shorter moieties of C₁₂E _n (e.g., n = 3, 4) as compared to higher ethereal oxygen content. The results of structural investigations with SANS and DLS to confirm this assumption are reported. The cloud point of C₁₂E _n has increased upon addition of SDS and decrease with NaCl, and a typical behavior is observed when both SDS and NaCl were present.     

Option pricing under a normal mixture distribution derived from the Markov tree model

We examine a Markov tree (MT) model for option pricing in which the dynamics of the underlying asset are modeled by a non-IID process. We show that the discrete probability mass function of log returns generated by the tree is closely approximated by a continuous mixture of two normal distributions. Using this normal mixture distribution and risk-neutral pricing, we derive a closed-form expression for European call option prices. We also suggest a regression tree-based method for estimating three volatility parameters σ, σ⁺, and σ⁻ required to apply the MT model. We apply the MT model to price call options on 89 non-dividend paying stocks from the S&P 500 index. For each stock symbol on a given day, we use the same parameters to price options across all strikes and expires. Comparing against the Black–Scholes model, we find that the MT model’s prices are closer to market prices.     

An efficient synthesis of benzyl bromides from aromatic aldehydes using polymethylhydrosiloxane and (bromodimethyl)sulfonium bromide or N-bromosuccinimide

Polymethylhydrosiloxane (PMHS) in combination with (bromodimethyl)sulfonium bromide or NBS has been utilized for the first time for reductive bromination of aromatic aldehydes at room temperature to afford the corresponding benzyl bromides in excellent yields.     

Salt induced micellization of very hydrophilic PEO-PPO-PEO block copolymers in aqueous solutions

Symmetrical poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide), PEO-PPO-PEO, triblock copolymers with 80% polyethylene oxide (PEO, the hydrophilic end blocks) and polypropylene oxide (PPO, the hydrophobic middle block) usually remain as molecularly dissolved at ambient temperature even at fairly high-concentrations (2 wt.% or more). However, the micellization is induced at lower concentration/temperature in the presence of salts. The results on salt induced micellization from four such hydrophilic copolymers Pluronic^® F38, F68, F88 and F108 obtained from several independent techniques are described. FTIR and fluorescence results provide essentially identical critical micelle temperatures (CMTs) showing marked decrease with increase in PPO molecular weight and in the presence of salt. These copolymers were weakly surface active and did not show a clear break point in surface tension concentration plot typical of surfactants. While addition of salt decreases the cloud point, no significant micelle growth was observed even at temperature close to cloud point (CP). Marked increased in solubilization of an oil dye was observed in presence of KCl. Different methods showed good agreement in temperature/salt-induced micellization of these hydrophilic copolymers.     

No More HF: Teflon‐Assisted Ultrafast Removal of Silica to Generate High‐Surface‐Area Mesostructured Carbon for Enhanced CO2 Capture and Supercapacitor Performance

An innovative technique to obtain high‐surface‐area mesostructured carbon (2545 m² g^?1) with significant microporosity uses Teflon as the silica template removal agent. This method not only shortens synthesis time by combining silica removal and carbonization in a single step, but also assists in ultrafast removal of the template (in 10 min) with complete elimination of toxic HF usage. The obtained carbon material (JNC‐1) displays excellent CO₂ capture ability (ca. 26.2 wt % at 0 °C under 0.88 bar CO₂ pressure), which is twice that of CMK‐3 obtained by the HF etching method (13.0 wt %). JNC‐1 demonstrated higher H₂ adsorption capacity (2.8 wt %) compared to CMK‐3 (1.2 wt %) at ?196 °C under 1.0 bar H₂ pressure. The bimodal pore architecture of JNC‐1 led to superior supercapacitor performance, with a specific capacitance of 292 F g^?1 and 182 F g^?1 at a drain rate of 1 A g^?1 and 50 A g^?1, respectively, in 1 m H₂SO₄ compared to CMK‐3 and activated carbon.     

PVC-based dicyclohexano-18-crown-6 sensor for La(III) ions

A new ion-selective electrode (ISE) based on dicyclohexano-18-crown-6 (DC18C6) as a neutral carrier is developed for lanthanum(III) ions. The electrode comprises of dicyclohexano-18-crown-6 (6%), PVC (33%), and ortho-nitrophenyl octyl ether (o-NPOE) (61%). The electrode shows a linear dynamic response in the concentration range of 10⁻⁶ to 10⁻¹ M with a Nernstian slope of 19 mV per decade and a detection limit as 5×10⁻⁷ M. It has a response time of <30 s and can be used for at least 5 months without any significant divergence in potentials. The selectivity coefficients for mono-, di-, and trivalent cations indicate good selectivity for La(III) ions over a large number of interfering cations. The sensor has been used as an indicator electrode in the potentiometric titrations of La(III) with EDTA. The membrane is successfully applied in partially non-aqueous medium. It can be used in the pH range 4-9.