Chemical Engineering Commons^™

Gomes, J.F.P., Bordado, J., Tomás, R., P-Xylene Oxidation To Terephthalic Acid. A Literature Review Oriented Toward Process Optimization And Development”, Chemical Reviews (2013), João F. Gomes

João F Gomes

No abstract provided.

Biodiesel Production From Waste Trying Oils Over Lime Catalysts, João F. Gomes

João F Gomes

No abstract provided.

Optimization And Modeling Of Microwave-Assisted Extraction Of Active Compounds From Cocoa (Theobroma Cacao L.) Leaves, Chung-Hung Chan C.-H Chan

Chung-Hung Chan C.-H Chan

Microwave-assisted extraction (MAE) is a promising plants extraction technique and it has the potential to be commercialized. However, due to limited significant parameters to describe the MAE process, optimization and modeling of MAE for scaling up are challenging and restricted. To resolve the problem, two intensive energy-related parameters, i.e. absorbed power density (APD) and absorbed energy density (AED) were introduced and they are respectively defined as the amount of microwave power (W/ml) and energy (J/ml) absorbed in the solvent during the extraction. Following that, three methods namely APD predictive method, AED modeling method and combined APD-AED optimization method were developed …

Optimization And Modeling Of Microwave-Assisted Extraction Of Active Compounds From Cocoa Leaves, Chung-Hung Chan C.-H Chan

Chung-Hung Chan C.-H Chan

Microwave-assisted extraction (MAE) is a promising plants extraction technique and it has the potential to be commercialized. However, due to limited significant parameters to describe the MAE process, optimization and modeling of MAE for scaling up are challenging and restricted. To resolve the problem, two intensive energy-related parameters, i.e. absorbed power density (APD) and absorbed energy density (AED) were introduced and they are respectively defined as the amount of microwave power (W/ml) and energy (J/ml) absorbed in the solvent during the extraction. Following that, three methods namely APD predictive method, AED modeling method and combined APD-AED optimization method were developed …

Power And Energy Requirement For Microwave-Assisted Extraction Of Anti-Diabetic Compounds From Cocoa Leaves, Chung-Hung Chan C.-H Chan, Rozita Yusoff R. Yusoff, Gek-Cheng Ngoh G.-C. Ngoh, Fabian Wai-Lee Kung

Chung-Hung Chan C.-H Chan

Microwave-assisted extraction (MAE) is widely employed to extract active compounds from plants. However, optimum operating conditions for MAE reported in literature are applicable only for specific scale of extraction and microwave system. This operational limitation was focused by taking into consideration the intrinsic power and energy required for optimizing the MAE in this study. Thus, the effects of absorbed microwave power density (APD) and absorbed microwave energy density (AED) on MAE of anti-diabetic compounds from cocoa (Theobroma cacao L.) leaves were investigated. This study suggests that APD addresses the real heating power of MAE and characterizes the extraction kinetics of …

Determination Of Optimum Extraction Time Of Larger Scale Mae Based On Absorbed Microwave Power, Chung-Hung Chan C.-H Chan, Rozita Yusoff R. Yusoff, Gek-Cheng Ngoh G.-C. Ngoh

Chung-Hung Chan C.-H Chan

A method was developed to predict the optimum extraction time for large scale microwave-assisted extraction (MAE) under various extraction conditions, i.e. solvent loading (100-300 ml) and microwave irradiation power (100-600 W). The method was established based on the correlation between optimum extraction time region and absorbed power density (APD) of the extraction system where APD is defined as the microwave power absorbed per unit solvent volume during extraction. This work provides an account on the procedure and the influencing factors amenable to the development of the proposed method. The predictive capability of the correlation was verified as the experimental optimum …

Determination Of Optimum Extraction Time Of Larger Scale Mae Based On Absorbed Microwave Power, Chung-Hung Chan C.-H Chan, Rozita Yusoff R. Yusoff, Gek-Cheng Ngoh G.-C. Ngoh

Chung-Hung Chan C.-H Chan

A method was developed to predict the optimum extraction time for large scale microwave-assisted extraction (MAE) under various extraction conditions, i.e. solvent loading (100-300 ml) and microwave irradiation power (100-600 W). The method was established based on the correlation between optimum extraction time region and absorbed power density (APD) of the extraction system where APD is defined as the microwave power absorbed per unit solvent volume during extraction. This work provides an account on the procedure and the influencing factors amenable to the development of the proposed method. The predictive capability of the correlation was verified as the experimental optimum …

Fast Catalytic Oxidation Of Phenol Over Modified Zeolite L Nanocrystals, Eng-Poh Ng Dr.

Eng-Poh Ng

Iron modified zeolite L nanocrystals (Fe/KL) were synthesized hydrothermally by the incorporation of Fe3+ in zeolite L lattice. XRD results showed an increase in the inter-planar spacing and lattice parameters. Transition characteristic of the tetrahedral Fe3+ species were observed in the UV–Vis spectrum. The oxidation of phenol in the presence of acetic acid over Fe/KL gave 93.40% conversion in 30 min with selective formation of 77.47% catechol and 22.53% hydroquinone. The catalytic activity was significantly enhanced by the addition of acetic acid. It was found that the acetic acid was oxidized by hydrogen peroxide to form peracetic acid, which served …

Chapter 5 Adsorption, Eng-Poh Ng Dr.

Eng-Poh Ng

No abstract provided.

Sulfonic Acid Functionalized Mcm-41 As Solid Acid Catalyst For Tert-Butylation Of Hydroquinone Enhanced By Microwave Heating, Eng-Poh Ng

Eng-Poh Ng

Covalently linked sulfonic acid (-SO3H) modified MCM-41 mesoporous catalysts was prepared, characterized and its catalytic activity under microwave irradiation was evaluated. The NH2-MCM-41 was first prepared by anchoring (3-aminopropyl)triethoxysilane (APTES) on Si-MCM-41 and further reacted with 1,4-butane-sultone to yield the desired acid catalyst. The mesophase and porosity of samples were determined by XRD, TEM and N2 sorption isotherm analyses. The presence of sulfonic acid moiety was confirmed by FT-IR, TG/DTA, sulfur elemental analysis and in situ IR study of pyridine and ammonia adsorptions. The catalyst showed high catalytic activity and high selectivity in tert-butylation of hydroquinone under microwave irradiation. No …

Kaa 507 Surface Analysis (Adsorption), Eng-Poh Ng Dr.

Eng-Poh Ng

No abstract provided.

Mechaniczny Rozdział Faz Proj., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Challenges And Prospects Of Processes Utilising Carbonic Anhydrase For Co2 Separation, Patrycja Szeligiewicz, Wojciech M. Budzianowski

Wojciech Budzianowski

This article provides an analysis of processes for separation CO2 by using carbonic anhydrase enzyme with particular emphasis on reactive-membrane solutions. Three available processes are characterised. Main challenges and prospects are given. It is found that in view of numerous challenges practical applications of these processes will be difficult in near future. Further research is therefore needed for improving existing processes through finding methods for eliminating their main drawbacks such as short lifetime of carbonic anhydrase or low resistance of reactive membrane systems to impurities contained in flue gases from power plants.

Novel Predictive Tools For Design Of Radiant And Convective Sections Of Direct Fired Heaters, A. Bahadori

No abstract provided.

Dynamic Metabolic Modeling Of A Microaerobic Yeast Co-Culture: Predicting And Optimizing Ethanol Production From Glucose/Xylose Mixtures, Timothy J. Hanly, Michael A. Henson

Michael A Henson

Background: A key step in any process that converts lignocellulose to biofuels is the efficient fermentation of both hexose and pentose sugars. The co-culture of respiratory-deficient Saccharomyces cerevisiae and wild-type Scheffersomyces stipitis has been identified as a promising system for microaerobic ethanol production because S. cerevisiae only consumes glucose while S. stipitis efficiently converts xylose to ethanol. Results: To better predict how these two yeasts behave in batch co-culture and to optimize system performance, a dynamic flux balance model describing co-culture metabolism was developed from genome-scale metabolic reconstructions of the individual organisms. First a dynamic model was developed for each …

Biophotonic Logic Devices Based On Quantum Dots And Temporally-Staggered Forster Energy Transfer Relays, Jonathan C. Claussen, W. Russ Algar, Niko Hildebrandt, Kimihiro Susumu, Mario G. Ancona, Igor L. Medintz

Jonathan C. Claussen

Integrating photonic inputs/outputs into unimolecular logic devices can provide significantly increased functional complexity and the ability to expand the repertoire of available operations. Here, we build upon a system previously utilized for biosensing to assemble and prototype several increasingly sophisticated biophotonic logic devices that function based upon multistep Förster resonance energy transfer (FRET) relays. The core system combines a central semiconductor quantum dot (QD) nanoplatform with a long-lifetime Tb complex FRET donor and a near-IR organic fluorophore acceptor; the latter acts as two unique inputs for the QD-based device. The Tb complex allows for a form of temporal memory by …

Mild Yet Phase-Selective Preparation Of Tio2 Nanoparticles From Ionic Liquids – A Critical Study, Tarek Alammar, Heshmat Noei, Yuemin Wang, Anja V. Mudring

Anja V. Mudring

The phase selective synthesis of nanocrystalline TiO2, titania, in ionic liquids (ILs) is explored. The influence not only of the IL but also of the Ti-precursor, pH, and temperature is investigated. Sonochemical synthesis, microwave synthesis and conventional heating are compared. In the case of Ti(OiPr)4 (OiPr ¼ isopropyl) as the Ti-source the ILs [C4mim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide), [C3mimOH][Tf2N] (1-(3-hydroxypropyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)amide), [C4Py]- [Tf2N] (butylpyridinium bis(trifluoromethanesulfonyl)amide), [N1888][Tf2N] (methyltrioctylammonium bis- (trifluoromethanesulfonyl)amide), and [P66614][Tf2N] (tetradecyltrihexyl phosphonium bis(trifluoromethanesulfonyl) amide) led at ambient temperature to TiO2 in the form of anatase. The morphology of nano-anatase is controlled by the IL cation. Anatase nanospheres with a crystal size …

Yttrium(Iii) Oxomolybdates(Vi) As Potential Host Materials For Luminescence Applications: An Investigation Of Eu3+-Doped Y2[Moo4]3 And Y2[Moo4]2[Mo2o7], Sonja Laufer, Sabine Strobel, Thomas Schleid, Joanna Cybinska, Anja V. Mudring, Ingo Hartenbach

Anja V. Mudring

Two ternary yttrium(III) oxomolybdates(VI) are investigated, both structurally and spectroscopically. The crystal structure of Y2[MoO4]3 was solved at room temperature in the orthorhombic space group Pba2 (a = 1030.21(3), b = 1032.41(3), c = 1057.25(3) pm, Z = 4). In the unit cell, three discrete ortho-oxomolybdate(VI) units [MoO4]2− and two Y3+ cations, both with CN = 7 featuring a monocapped trigonal-prismatic oxygen environment, can be distinguished. Y2[MoO4]2[Mo2O7] crystallizes monoclinically in the space group P21/c (a = 681.85(2), b = 959.13(3), c = 1052.99(3) pm, β = 105.586(2)°) with two formula units per unit cell. In this compound the anionic environment …

Refactoring The Silent Spectinabilin Gene Cluster Using A Plug-And-Play Scaffold, Zengyi Shao, Guodong Rao, Chun Li, Zhanar Abil, Yunzi Luo, Huimin Zhao

Zengyi Shao

Natural products (secondary metabolites) are a rich source of compounds with important biological activities. Eliciting pathway expression is always challenging but extremely important in natural product discovery because an individual pathway is tightly controlled through a unique regulation mechanism and hence often remains silent under the routine culturing conditions. To overcome the drawbacks of the traditional approaches that lack general applicability, we developed a simple synthetic biology approach that decouples pathway expression from complex native regulations. Briefly, the entire silent biosynthetic pathway is refactored using a plug-and-play scaffold and a set of heterologous promoters that are functional in a heterologous …

Activation And Characterization Of A Cryptic Polycyclic Tetramate Macrolactam Biosynthetic Gene Cluster, Yunzi Luo, Hua Huang, Jing Liang, Meng Wang, Lu Lu, Zengyi Shao, Ryan E. Cobb, Huimin Zhao

Zengyi Shao

Polycyclic tetramate macrolactams (PTMs) are a widely distributed class of natural products with important biological activities. However, many of these PTMs have not been characterized. Here we apply a plug-and-play synthetic biology strategy to activate a cryptic PTM biosynthetic gene cluster SGR810-815 from Streptomyces griseus and discover three new PTMs. This gene cluster is highly conserved in phylogenetically diverse bacterial strains and contains an unusual hybrid polyketide synthase-nonribosomal peptide synthetase, which resembles iterative polyketide synthases known in fungi. To further characterize this gene cluster, we use the same synthetic biology approach to create a series of gene deletion constructs and …