Process Intensification Through Miniaturization of Chemical and Thermal Systems in the 21st Century

Wegeng, Robert S.; Drost, M.K.; Brenchley, David L.

doi:10.1007/978-3-642-59738-1_1

Cited by 26 publications

(16 citation statements)

References 3 publications

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“…These benefits translate into a small device size, which is ideal for integration into portable and distributed systems ( Fig. 1) (Urval 2004;Wegeng et al 1999). One example of this developing technology is a microchannel device for improved hemodialysis, which is under development at Oregon State University.…”

Section: Introductionmentioning

confidence: 97%

Nano-enabled microtechnology: polysulfone nanocomposites incorporating cellulose nanocrystals

2007

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Microchannel devices hold the potential to transform many separation processes. This preliminary study investigated the feasibility of incorporating cellulose nanocrystals (CNXLs) into polysulfone, a commonly used ultrafiltration membrane polymer. Incorporating CNXLs into non-water soluble polymers without aggregation has been problematic. A solvent exchange process was developed that successfully transferred an aqueous CNXL dispersion into the organic solvent N-methylpyrrolidone (NMP), which is a solvent for polysulfone (PSf). Films were prepared from the solution of PSf in NMP with dispersed CNXLs by a phase inversion process. Films were then examined by scanning electron microscopy and tested for their transport and mechanical properties. The interaction between the polymer matrix and the CNXL filler was studied by means of thermogravimetric analysis (TGA), which suggested a close interaction between the polymer and filler at the 2% filler loading. The tensile modulus showed a large increase beyond 1% filler loading, which could be due to a percolation effect. The water vapor transport rate increased with increase in filler loading. Agglomeration of the CNXLs seemed to be taking place at filler loadings >7%.

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Section: Introductionmentioning

confidence: 97%

Nano-enabled microtechnology: polysulfone nanocomposites incorporating cellulose nanocrystals

2007

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“…Based on its unique miniaturisation approach and the fact that all reactions are carried out under flow-through conditions, MRT enables excellent control of reaction parameters such as temperature and concentration equipartition, thus allowing in many cases higher yields, fewer by-products and higher selectivity. Therefore, it has become increasingly interesting for small-scale production in the pharmaceutical and fine chemical industry [1]. This approach is strongly driven by the idea of shortening development periods of new active substances by consequently numbering-up [2] in order to avoid scale-up risks.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of a Library of Ciprofloxacin Analogues By Means of Sequential Organic Synthesis in Microreactors

Schwalbe¹,

Kadzimirsz²,

Jas³

2005

QSAR Comb. Sci.

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The realm of combinatorial chemistry is strongly based on the concept of parallel chemistry and its ease of automation. Although this batch-type approach in general may be considered a success story, some limitations remain rarely addressable by conventional approaches. Particularly, scaling-up problems such as the re-synthesis of multigram amounts of active compounds as well as the synthesis of building blocks and scaffolds in large amounts may prove to be problematic. Our expertise in continuous chemistry prompted us to develop a microreaction system for sequential organic synthesis that should overcome these limitations. In the present contribution we describe this system as well as its application to the first library approach towards fluoro-quinolone antibiotics such as Ciprofloxacin solely using microreaction technology. A known one-pot batch procedure for the synthesis of this compound class was split in its individual reaction steps, which were successfully adapted to a continuous conduct. After some optimisation studies the overall sequence was suitable for chemical diversification. Particularly it was shown, that the first step of the synthesis -the acylation reaction of a b-dimethylamino acrylate with trifluoro-benzoic acid chloride -was accessible to synthesis of high quantities without any difficulties to yield a primary building block suitable for subsequent library synthesis. In a first diversification step, the Michael addition of a set of primary amines was followed by nucleophilic ring closure providing the difluoroquinolone system, which was subjected to a second diversification step by means of a nucleophilic aromatic substitution reaction. Thus, a number of Ciprofloxacin analogues could be synthesised in good overall yield and purity. Isolated yields ranged from 71 to 85% in the first diversification step and from 59 to 99% in the second step.

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“…44) [167,169± 174,176,180,182]. PNNL work is governed by the strategy to employ microreactors for mobile tasks concerned with energy supply and temperature control [174,183], in particular focusing on outer space and military applications [175,184,185]. As an example for outer space research, fuel generation in microreactors is tested, e.g.…”

Section: Minireformer ± Fuel Cell Applicationsmentioning

confidence: 99%

Microchemical Engineering: Components, Plant Concepts, User Acceptance – Part II

Hessel

Löwe

2003

Chem Eng & Technol

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Over the last five years, many activities have focused on the unexploited field of carrying out reactions on small scales. Due to the rapid development of new components, this paper deals with recent developments only in a compressed form. An important point is the analysis of possible plant concepts for microreactors and whether these are a sensible option. Due to the enormous difference in size between the microchannels and the fluid periphery of possible components this is not just a technical question. It touches on the microtechnology concept as a whole. The direction in which the field should be developed and which measures can be taken to influence its development are questions that are addressed here with respect to the big industrial interest in microreactors. Reactors for Photochemical and Electrochemical ProcessingMicroreactors may possibly be capable of reevaluating processes which so far have been poorly developed both in the lab and in the chemical industry. Among such processs certainly are electrochemical reactions and particularly photochemical reactions. Photochemical and Electrochemical ProcessesIn view of the low quantum yield of photochemical processes even for respective lab-scale equipment, it would appear that guiding of thin fluid layers in transparent microreactors, e.g. mixer-reactors, in close proximity to a radiation source should be beneficial. At the Massachusetts Institute of Technology (MIT), Cambridge (USA), researchers carried out the pinacol synthesis using benzophenone as reactant in a pyrex/silicon microreactor equipped with a miniature UV lamp (k = 366 nm) (see Fig. 20) [98,99].An electrochemical microreactor was developed at IMM which combines the advantages of thin-layer cell technology (namely, current efficiencies up to 100 %, absence of conducting salt) and microchemical processing (e.g., isothermal processing, good mass transfer). The electrochemical microreactor has a parallel-plate architecture. Using this device, an increase in selectivity for the synthesis of anisaldehyde from 4-methoxytoluene was detected [100]. Heat Transfer Fast Heating up for Chlorination of AlkanesThe chlorination of alkanes [102] performed by the Axiva company serves as a good and successful example based on the motto ªas much miniaturization as necessary, not as possibleº. The tube reactors used till now needed too much time to reach a certain temperature level or even exhibited temperature maxima above the target value, in effect similarly detrimental as a hot spot. To improve these features, IMM developed monolithic heating modules that are externally heated. The . UV absorption of reaction mixtures resulting from pinacol reaction using benzophenone in isopropanol at various flow rates and residence times, respectively. A comparison of these results to HPLC measurements at the same mixtures reveals that these UV in-line spectra are accurate and hence can be used to monitor the course of reaction. Source: K. Jensen, MIT, Department of Chemical Engineering, Cambridge (USA)

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Process Intensification Through Miniaturization of Chemical and Thermal Systems in the 21st Century

Cited by 26 publications

References 3 publications

Nano-enabled microtechnology: polysulfone nanocomposites incorporating cellulose nanocrystals

Nano-enabled microtechnology: polysulfone nanocomposites incorporating cellulose nanocrystals

Synthesis of a Library of Ciprofloxacin Analogues By Means of Sequential Organic Synthesis in Microreactors

Microchemical Engineering: Components, Plant Concepts, User Acceptance – Part II

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