Application of Rosin–Rammler model for analysis of CSD in sugar crystallization

Crystal‐size distribution (CSD) is one of the most important parameters in sugar production. The objective is to grow crystals of uniform sizes or narrow CSD. CSD appears to be determined by the growth‐rate history of the crystals and the relative supersaturation (SS) of the solution from which crystals growth takes place. Three methods for preparation of nucleation seeds were described and used for industrial crystallization of raw and white sugars; these are wet milling filtered sugar (ML), agitating saturated solution (AS) and powdered sugars (PD). Rosin–Rammler (RR) and mathematical models were adopted to investigate CSD and the uniformity of the produced crystals. Higher uniformity coefficients were reported for the AS seeded crystals than the other two seeding methods. Furthermore, higher crystal contents were obtained for the AS seeded white sugar batches in comparison.     

Solvent-free Efficient Synthesis of Symmetrical Isocyanurates by a Combination Catalyst: Sodium Saccharin and Tetrabutylammonium Iodide

Combination of sodium saccharin and tetrabutylammonium iodide as a novel anionic catalyst system promotes selectively the trimerization of isocyanates to give symmetrical isocyanurates under solvent-free conditions.     

Optimal preventive maintenance policy for electric power distribution systems based on the fuzzy AHP methods

In power distribution systems, with their great vastness and various outage causes, one of the most important problems of power distribution companies is to select a suitable maintenance strategy of system elements and method of financial planning for the maintenance of system elements with the two objectives of decrease in outage costs and improvement of system reliability. In this article, a practical method is introduced for the selection of a suitable system elements maintenance strategy; moreover, to plan the preventive maintenance budget for the system elements, two methods are offered: the cost optimization method and the fuzzy Analytic Hierarchy Process (AHP) method. In the former method, a new model of system maintenance cost is offered. This model, based on system outage information, the elements maintenance costs are determined as functions of system reliability indices and preventive maintenance budget. The latter method, too, a new guideline is introduced for considering the cost and reliability criteria in the trend of preventive maintenance budget planning. In this method, the preventive maintenance budget for the elements is determined based on relative priority of elements with reliability criteria. © 2015 Wiley Periodicals, Inc. Complexity 21: 70–88, 2016     

Highly active recyclable heterogeneous nanonickel ferrite catalyst for cyanation of aryl and heteroaryl halides

Magnetic nickel ferrite nanoparticles are found to be an efficient catalytic system for cyanation reactions of various types of aryl halides under conventional heating conditions. All the reactions result in very good to excellent yields under optimized reaction conditions. Furthermore, the catalyst is easily removed from the reaction medium and can be reused further in several subsequent runs. Copyright © 2014 John Wiley & Sons, Ltd.     

Facile entry to polycyclic indolylhydroquinoline skeletons via tandem C-alkylation and intramolecular S-alkylation

An efficient, single step synthesis of hitherto unknown indole-annulated pentacyclic indolylhydroquinolines via tandem C-alkylation and intramolecular S-alkylation of indolin-2-thiones with N-alkylquinolinium salts in excellent yields (83-95%) is reported. This facile approach provides a powerful entry into polycyclic structures containing nitrogen and sulfur related to alkaloids. The structure of the product was determined by Röntgen crystal structure analysis.     

A Facile Synthesis of Bridged Polycyclic Naphthooxazocine Skeletons: Eight‐Membered‐Ring Constructions via Tandem Dinucleophilic Addition of Naphthalenols to Quinolinium Salts

The efficient synthesis of bridged polycyclic naphthooxazocines 3 via addition of naphthalenols 1 as a bis‐nucleophile to N‐alkylquinolinium salts 2 is described (Scheme 1 and Table 2). This new approach provides a powerful entry into polycyclic structures containing bicyclic N,O‐acetals related to bioactive compounds.     

Convenient synthesis of chlorohydrins from epoxides using zinc oxide: Application to 5,6‐epoxysitosterol

Efficient synthesis of protected and unprotected chlorohydrins has been achieved by ring opening of epoxides with acetyl/benzoyl chloride and TMSCl using a catalytic amount of ZnO as a reusable catalyst. The applicability of ZnO is further extended by performing the cleavage of the natural product 5,6‐epoxysitosterol with acetyl chloride. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:157–163, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20529     

Induction asymetrique lors de l'addition de Michael d'un ester α-sulfinyle chiral

During the Michael addition of chiral α-sulfinyl eser (+) $\text{1}$$\text{R}$ on αβ-unsaturated esters, an extent of 24% of asymmetric induction was observed. It is shown that the addition products can be transformed into optically active δ-lactones.     

N‐Benzyl DABCO Tribromide–Promoted Oxidative Coupling of Benzyl Cyanides: A Convenient Procedure for the Synthesis of α, α′‐Dicyanostilbenes

A convenient and efficient procedure was developed for preparing α,α′‐icyanostilbenes through the oxidative coupling reaction of benzyl cyanide derivatives using N‐benzyl DABCO tribromide as the oxidative bromination reagent in the presence of K₂CO₃ as a base.