SbCl3-Catalyzed conversion of ketones and aldehydes into gem-dihydroperoxides (DHPs) with 30% H2O2

A simple and efficient conversion of ketones and aldehydes into corresponding gem-dihydroperoxides (DHPs) has been developed by SbCl3-catalyzed oxidation with 30% H2O2 at room temperature. The reactions proceeded smoothly under mild conditions at room temperature. Simple experimental procedure, use of inexpensive and non-toxic catalyst, high yields and low reaction times are the main merits of the present method

Leucine: green and efficient catalyst for the synthesis of 4H-chromenes

Leucine, a naturally occurring α-amino acid, has been found as an effective catalyst to effect the one-pot three-component condensation reaction between aromatic aldehydes, malononitrile and 5,5-dimethyl-1,3-cyclohexanedione (dimedone). Various 2-amino-4-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile derivatives are conveniently prepared by these reactions in excellent yields. High yields, short reaction times, simple work-up, use of green and naturally occurring catalyst and solvent are the main merits of the present protocol.&nbsp

Synthesis and characterization of organic conjugated polymer/ ZnO nano-particle films for solar cell application

Hybrid thin films show great promise as a novel material for solar energy conversion devices. Using present knowledge from polymer bulk hetero-junction solar cells, the design of a simple, and potentially low cost, hybrid solar cell based on metal oxides and conjugated polymers is presented. The hybrid material properties are often superior to the sum of the intrinsic properties of the components and often have a functionality that is not present in either of the individual materials [1]. In this research, hybridization of organic conducting polymer and metal oxide semiconductor on nanometer scale in fabricating of a bulk hetero-junction solar cell will be investigated. ZnO nanoparticles were chosen as nanoparticle semiconductors and Poly(3-hexylthiophene-2,5-diyl) (P3HT) is used as a conductive polymer. ZnO and P3HT are individually very important functional materials. Additionally, ZnO nanoparticles have transparency over the whole visible region and have good electron mobility compared to other wide band gap materials such as TiO2 [61,62]. The P3HT semiconductor polymer is important because of its high absorption coefficient in the visible region. In addition to the aforementioned intrinsic properties of these functional materials, in the hybrid of ZnO/P3HT energy levels of ZnO nanoparticles and P3HT polymer are matching and the hybrid layer can act as an active layer to absorb the visible solar light and release the electric charges. Uniform ZnO nanoparticles with small particle size distribution were synthesized. High resolution TEM imaging was performed to study the size and shape of the ZnO nanoparticles. The synthesized particles mainly range between 5-7 nm. To prepare the ZnO/P3HT hybrid solution we optimized the dispersion of the ZnO nanoparticles in the methanol/chloroform mixture solution (avoiding ZnO agglomeration). We obtained good dispersion of ZnO nanoparticles in a mixed solution of 4.5% methanol and 95.5% chloroform. Glass coated with ITO was used as a substrate followed by a poly (3,4ethylenedioxythiophene) poly (styrene sulfonate) (PEDOT:PSS) layer, spin coated on the ITO substrate. Above the PEDOT:PSS layer we spin coated a hybrid (ZnO/P3HT) layer followed by depositing aluminium electrodes using the metal evaporation technique. We studied the quality of the film formation and the aluminium electrodes using optical and scanning electron microscopies. Also we studied the absorption and emission hybrid films using UV-Visible and florescent spectroscopies. By changing the blend (ZnO/P3HT) concentration and the ratio of ZnO and P3HT as the initial parameters we could optimise the optical properties. 5 mg/mL ZnO nanoparticles and 10 mg/mL P3HT concentrations with 50% ZnO and 50% P3HT ratio resulted in the best optical characteristics in the hybrid films. The concentration of the PEDOT:PSS was also optimised. We found that 0.65% PEDOT:PSS concentration results the highest electrical measurements of the prepared Bulk heterojunction solar cell. Using the optimised parameters we prepared the bulk hetero-junction solar cells and conducted the electrical tests including incident photon to electron conversion efficiency IPCE and J-V characterization. We found that optimized parameters resulted in 19% IPCE and 1.13 mA.Cm-2 ISC and 0.23 VOC. We chose three prepared solar cells; 1. best performing with 50% -50% ZnO/P3HT ratio , 2.worst performing with 50% -50% ZnO/P3HT ratio 3. solar cell with 30%-70% ZnO/P3HT ratio) to study the morphology of their hybrid layer using AFM and surface profiler. Up to some extend we could understand and relate the hybrid film morphologies to the obtained electrical performance of these three bulk hetero-junction solar cells. In compar to other lab-prepared bulk hetero-junction solar cells the best performing bulk hetero-junction solar cell has a better hybrid film uniformity. Also in the best performing bulk hetero-junction solar cell the roughnesses and mean granular sizes of the film over the surface were very similar. We used AFM to correlate the quality of the film surface with the electrical performance and found that uniform and continuous films are very important in the performance of the solar cell device

Regioselective and facile oxidative thiocyanation of anilines and indoles with trans-3,5?dihydroperoxy-3,5?dimethyl?1,2?dioxolane

Oxidative potential of trans3,5dihydroperoxy3,5dimethyl1,2dioxolane (DHPODMDO) has been explored in the facile thiocyanation of anilines and indoles through the efficient and in situ generation of SCN+ ion from sodium thiocyanate. The reactions proceed with regioselectivity under mild conditions at room temperature to afford the respective thiocyanate derivatives in excellent yields and low reaction times

LEUCINE : AN EFFICIENT AND GREEN AMINO ACID CATALYST FOR CONVERSION OF ALDEHYDES AND KETONES INTO GEM-DIHYDROPEROXIDES WITH H2O2

Leucine amino acid, has been explored as an effective catalyst for conversion of ketones and aldehydes into corresponding gem-dihydroperoxides using 30% aqueous hydrogen peroxide in acetonitrile at room temperature. The reactions proceed smoothly within short periods of time to provide the respective gem-dihydroperoxides in excellent yields. Mild reaction conditions, low reaction times, high yields, low environmental impact, use of non-expensive, recyclable and green catalyst are the main merits of the present method

Cu(II)-Schiff base covalently anchored to MIL-125(Ti)-NH2 as heterogeneous catalyst for oxidation reactions

[EN] MIL-125(Ti)-NH2 has been modified by reaction of salicylaldehyde with the terephthalate amino groups to form a salicylideneimine that act as ligand of Cu2+. The success of the postsynthetic modification was assessed by FTIR spectroscopy of the MIL-125(Ti)-NH2-Sal-Cu and by analysis by H-1 NMR spectroscopy of the organic linkers upon dissolution of MIL-125(Ti)-NH2-Sal-Cu. In comparison with parent MIL-125(Ti)-NH2 and MIL-125(Ti)-NH2-Sal, that exhibit a poor activity, the presence of the Cu-Schiff base complex in MIL-125(Ti)-NH2-Sal-Cu catalyst for the oxidation of 1-phenylethanol by tert-butylhydroperoxyde (TBHP, 3 eq.) increases notably the catalytic activity. Hot filtration test and reusability experiments confirm that the process is heterogeneous and that MIL-125(Ti)-NH2-Sal-Cu is stable under the reaction conditions. Quenching studies and EPR spectra using N-(t)butylphenylnitrone indicate the generation of (BuOO)-Bu-t. and (BuO center dot)-Bu-t under the reaction conditions. The scope of MIL-125(Ti)-NH2-Sal-Cu as oxidation catalyst by (BuOOH)-Bu-t was studied for benzyl alcohol as well as alicyclic and aliphatic alcohols and ethylbenzene. (C) 2018 Elsevier Inc. All rights reserved.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa) CTQ2014-53292-R is gratefully acknowledged. Generalidad Valenciana is also thanked for funding (Prometeo 2017/063). S.D., A.R.O., D.A., and R.G-V thank H.G., S.N. and M.A., S.D., D.A., and R.G-V gratefully acknowledge financial support from Bu-Ali Sina University. S.N. thanks financial support by the Fundacion Ramon Areces (XVIII Concurso Nacional para la Adjudicacion de Ayudas a la Investigacion en Ciencias de la Vida y de la Materia, 2016).Daliran, S.; Santiago-Portillo, A.; Navalón Oltra, S.; Reza Oveisi, A.; Alvaro Rodríguez, MM.; Ghorbani-Vaghei, R.; Azarifar, D.... (2018). Cu(II)-Schiff base covalently anchored to MIL-125(Ti)-NH2 as heterogeneous catalyst for oxidation reactions. Journal of Colloid and Interface Science. 532:700-710. https://doi.org/10.1016/j.jcis.2018.07.140S70071053

Acetic acid-promoted condensation of o-phenylenediamine with aldehydes into 2-aryl-1-(arylmethyl)-1H-benzimidazoles under microwave irradiation

Abstract: An efficient and simple procedure was developed for the green synthesis of various 2-aryl-1-(arylmethyl)-1H-benzimidazoles in high yields by acetic acid-promoted condensation of o-phenylenediamine with aldehydes in air under microwave irradiation and transition metal catalystfree conditions

Kartezyen Hesaplama Ağları Kullanılarak Üç Boyutlu Sıkıştırılabilir Akışlar için Navier-Stokes Çözücüsü Geliştirilmesi

TÜBİTAK MAG Proje01.06.2017Bu proje çerçevesinde Kartezyen hesaplama ağları için üç boyutlu bir Navier-Stokes çözücüsü geliştirilmiştir. Hesaplama ağının üretimi ile akış alanının çözümü aşamaları arasında gerekli olan kullanıcı müdahalesini ortadan kaldırmak üzere geliştirilecek yazılımın tam otomatik olarak gerçekleştirilmiştir. Akış alanındaki gövdenin geometrisi yapısal olmayan üçgen elemanlar kullanılarak üç boyutlu bir yüzey hesaplama ağı şeklinde verildiğinde, gövde uyumlu (body-fitted) üçgen prizma elemanlardan oluşan hesaplama ağı gövde geometrisinin şişirilmesiyle otomatik olarak oluşturulmaktadır. Daha sonra, gövde uyumlu hesaplama ağı, çözüm alanının sınırlarını tanımlayan bir kök hücrenin eşit hücrelere bölünmesi ile elde edilen Kartezyen hesaplama ağının içerisine yerleştirilmektedir. Her iki hesaplama ağının arasında kalan bölge dört yüzlü tetrahedral elemanlarla doldurulmaktadır. Navier-Stokes denklemlerinin sonlu hacim formülasyonu hücre merkezli yaklaşımla kullanılmaktadır. Hücre yüzlerindeki akılar akı fark ayrıştırması ve akı vektör ayrıştırması yöntemleriyle hesaplanmaktadır. Uzayda ikinci dereceden doğruluk elde edilebilmesi için basit değişkenlerin yeniden oluşturulmasında (reconstruction) yol tümleme (path integration) ve asgari kareler (least squares) yöntemleri kullanılmaktadır. Doğru ve sınırlı değerler elde edilebilmesi için yeniden oluşturma işlemi sırasında limitleyiciler kullanılmaktadır. Türbülans modeli olarak ise literatürde mevcut modellerden bir denklemli SpalartAllmaras türbülans modeli ile iki denklemli k-e ve k-w türbülans modellerinden yararlanılmaktadır. Yakınsamanın hızlandırılabilmesi için yerel zaman adımlarıyla birlikte çok kademeli (multistage) zaman adımlaması kullanılmaktadır. Çözüme bağlı hesaplama ağı adaptasyonu çözüm ile ağ arasındaki uyumun oluşmasını sağlayarak, akıştaki kritik bölgelerin daha iyi çözümlenmesine olanak sağlamaktadır. Çözüm adaptasyonu kayma tabakalarında hız dönümü, normal ve oblik şoklarda ise hız gradyanı kullanılarak gerçekleştirilmektedir. Geliştirilen yazılım NACA 0012 ve ONERA M6 kanadı etrafındaki üç boyutlu akış için test edilmiş ve elde edilen sayısal sonuçlar literatürde mevcut deneysel sonuçları ile karşılaştırılarak doğrulanmıştır

Covalent modification of reduced graphene oxide with piperazine as a novel nanoadsorbent for removal of H2S gas

In the present research, piperazine grafted-reduced graphene oxide RGO-N-(piperazine) was synthesized through a three-step reaction and employed as a highly efficient nanoadsorbent for H2S gas removal. Temperature optimization within the range of 30–90 °C was set which significantly improved the adsorption capacity of the nanoadsorbent. The operational conditions including the initial concentration of H2S (60,000 ppm) with CH4 (15 vol%), H2O (10 vol%), O2 (3 vol%) and the rest by helium gas and gas hour space velocity (GHSV) 4000–6000 h−1 were examined on adsorption capacity. The results of the removal of H2S after 180 min by RGO-N-(piperazine), reduced graphene oxide (RGO), and graphene oxide (GO) were reported as 99.71, 99.18, and 99.38, respectively. Also, the output concentration of H2S after 180 min by RGO-N-(piperazine), RGO, and GO was found to be 170, 488, and 369 ppm, respectively. Both chemisorption and physisorption are suggested as mechanism in which the chemisorption is based on an acid–base reaction between H2S and amine, epoxy, hydroxyl functional groups on the surface of RGO-N-(piperazine), GO, and RGO. The piperazine augmentation of removal percentage can be attributed to the presence of amine functional groups in the case of RGO-N-(piperazine) versus RGO and GO. Finally, analyses of the equilibrium models used to describe the experimental data showed that the three-parameter isotherm equations Toth and Sips provided slightly better fits compared to the three-parameter isotherms