scholarly journals Slug flow as tool for selectivity control in the homogeneously catalysed solvent-free epoxidation of methyl oleate

2021 ◽  
Author(s):  
Anoj Winston Gladius ◽  
Johanna Vondran ◽  
Yashwanth Ramesh ◽  
Thomas Seidensticker ◽  
David William Agar
Keyword(s):  
Methyl Oleate ◽  
Slug Flow ◽  
Space Time ◽  
Solvent Free ◽  
Water Soluble ◽  
Oxidation Products ◽  
Flow Mode ◽  
Physical Parameters ◽  
Selectivity Control ◽  
Space Time Yield

AbstractCatalytic oxidation of sustainable raw materials like unsaturated fats and oils, or fatty acids and their esters, lead to biobased, high-value products. Starting from technical grade methyl oleate, hydrogen peroxide as a green oxidant produces only water as by-product. A commercially available, cheap water-soluble tungsten catalyst is combined with Aliquat® 336 as a phase-transfer agent in solvent-free reaction conditions. In this study, we first report the transfer of this well-known batch system into continuous mode. The space–time yield is improved from 0.08 kg/L.h in batch to 1.29 kg/L.h in flow mode. The improved mass transfer and reduced back mixing of the biphasic liquid–liquid slug flow allows for selectivity control depending on physical parameters of slug flow namely volumetric phase ratio, volumetric flow rate, and slug length. Even though the product, methyl 9,10-epoxystearate is obtained at a maximum selectivity of only 58% in flow mode, higher space time yield combined with possible reactant recycling in flow mode offers a promising avenue of research. This work analyses the use of slug flow parameters as tools for controlling selectivity towards oxidation products of methyl oleate.

One-step, ultrasonication-mobilized, solvent-free extraction/synthesis of nanocurcumin from turmeric

RSC Advances ◽  
2015 ◽  
Vol 5 (60) ◽  
pp. 48391-48398 ◽  
Author(s):  
Judy Gopal ◽  
Manikandan Muthu ◽  
Se-Chul Chun
Keyword(s):  
Solvent Free ◽  
Water Soluble ◽  
One Step

One step ultrasonication for direct recovery of water soluble nanocurcumin from turmeric.

scholarly journals Construction and characterization of a novel glucose dehydrogenase-leucine dehydrogenase fusion enzyme for the biosynthesis of l-tert-leucine

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Langxing Liao ◽  
Yonghui Zhang ◽  
Yali Wang ◽  
Yousi Fu ◽  
Aihui Zhang ◽  
...  
Keyword(s):  
Glucose Dehydrogenase ◽  
Catalytic Efficiency ◽  
Space Time ◽  
Cofactor Regeneration ◽  
Enzyme Complex ◽  
Regeneration System ◽  
Regeneration Rate ◽  
Leucine Dehydrogenase ◽  
Fusion Enzyme ◽  
Space Time Yield

Abstract Background Biosynthesis of l-tert-leucine (l-tle), a significant pharmaceutical intermediate, by a cofactor regeneration system friendly and efficiently is a worthful goal all the time. The cofactor regeneration system of leucine dehydrogenase (LeuDH) and glucose dehydrogenase (GDH) has showed great coupling catalytic efficiency in the synthesis of l-tle, however the multi-enzyme complex of GDH and LeuDH has never been constructed successfully. Results In this work, a novel fusion enzyme (GDH–R3–LeuDH) for the efficient biosynthesis of l-tle was constructed by the fusion of LeuDH and GDH mediated with a rigid peptide linker. Compared with the free enzymes, both the environmental tolerance and thermal stability of GDH–R3–LeuDH had a great improved since the fusion structure. The fusion structure also accelerated the cofactor regeneration rate and maintained the enzyme activity, so the productivity and yield of l-tle by GDH–R3–LeuDH was all enhanced by twofold. Finally, the space–time yield of l-tle catalyzing by GDH–R3–LeuDH whole cells could achieve 2136 g/L/day in a 200 mL scale system under the optimal catalysis conditions (pH 9.0, 30 °C, 0.4 mM of NAD+ and 500 mM of a substrate including trimethylpyruvic acid and glucose). Conclusions It is the first report about the fusion of GDH and LeuDH as the multi-enzyme complex to synthesize l-tle and reach the highest space–time yield up to now. These results demonstrated the great potential of the GDH–R3–LeuDH fusion enzyme for the efficient biosynthesis of l-tle.

scholarly journals Development of a versatile source apportionment analysis based on positive matrix factorization: a case study of the seasonal variation of organic aerosol sources in Estonia

2019 ◽  
Vol 19 (11) ◽  
pp. 7279-7295 ◽  
Author(s):  
Athanasia Vlachou ◽  
Anna Tobler ◽  
Houssni Lamkaddam ◽  
Francesco Canonaco ◽  
Kaspar R. Daellenbach ◽  
...  
Keyword(s):  
Matrix Factorization ◽  
Organic Aerosol ◽  
Positive Matrix Factorization ◽  
Water Soluble ◽  
Oxidation Products ◽  
Positive Matrix ◽  
Bootstrap Analysis ◽  
Seasonal Behavior ◽  
Yearly Cycle ◽  
Aerosol Mass

Abstract. Bootstrap analysis is commonly used to capture the uncertainties of a bilinear receptor model such as the positive matrix factorization (PMF) model. This approach can estimate the factor-related uncertainties and partially assess the rotational ambiguity of the model. The selection of the environmentally plausible solutions, though, can be challenging, and a systematic approach to identify and sort the factors is needed. For this, comparison of the factors between each bootstrap run and the initial PMF output, as well as with externally determined markers, is crucial. As a result, certain solutions that exhibit suboptimal factor separation should be discarded. The retained solutions would then be used to test the robustness of the PMF output. Meanwhile, analysis of filter samples with the Aerodyne aerosol mass spectrometer and the application of PMF and bootstrap analysis on the bulk water-soluble organic aerosol mass spectra have provided insight into the source identification and their uncertainties. Here, we investigated a full yearly cycle of the sources of organic aerosol (OA) at three sites in Estonia: Tallinn (urban), Tartu (suburban) and Kohtla-Järve (KJ; industrial). We identified six OA sources and an inorganic dust factor. The primary OA types included biomass burning, dominant in winter in Tartu and accounting for 73 % ± 21 % of the total OA, primary biological OA which was abundant in Tartu and Tallinn in spring (21 % ± 8 % and 11 % ± 5 %, respectively), and two other primary OA types lower in mass. A sulfur-containing OA was related to road dust and tire abrasion which exhibited a rather stable yearly cycle, and an oil OA was connected to the oil shale industries in KJ prevailing at this site that comprises 36 % ± 14 % of the total OA in spring. The secondary OA sources were separated based on their seasonal behavior: a winter oxygenated OA dominated in winter (36 % ± 14 % for KJ, 25 % ± 9 % for Tallinn and 13 % ± 5 % for Tartu) and was correlated with benzoic and phthalic acid, implying an anthropogenic origin. A summer oxygenated OA was the main source of OA in summer at all sites (26 % ± 5 % in KJ, 41 % ± 7 % in Tallinn and 35 % ± 7 % in Tartu) and exhibited high correlations with oxidation products of a-pinene-like pinic acid and 3-methyl-1, 2, 3-butanetricarboxylic acid (MBTCA), suggesting a biogenic origin.

Synthesis of pure and uniform nano-sized TS-1 crystal with high titanium content and high space-time yield

2021 ◽  
Author(s):  
Lejian Zhang ◽  
Xiaoxiao Zhu ◽  
Xinping Wang ◽  
Chuan Shi
Keyword(s):  
Selective Oxidation ◽  
Cost Efficiency ◽  
Environmental Issues ◽  
Titanium Content ◽  
Space Time ◽  
Titanium Silicalite ◽  
Oxidation Reactions ◽  
High Space ◽  
Space Time Yield ◽  
Selective Oxidation Reactions

Anatase-free titanium silicalite-1 (TS-1) zeolite with high framework titanium content is highly required for catalysing selective oxidation reactions, while its synthesis generally suffers from cost, efficiency and environmental issues. Herein,...

Micro-Treatment Mechanism Study on Ionic Soil Stabilizer Improving Clay

2015 ◽  
Vol 667 ◽  
pp. 370-375 ◽  
Author(s):  
Xiao Hua Luo ◽  
Xin Qiu ◽  
Yu Jie Wang ◽  
Jin Hong Wu ◽  
Shang Lin Xiao
Keyword(s):  
Organic Matter Content ◽  
Emission Spectra ◽  
Particle Size Analysis ◽  
Matter Content ◽  
Water Soluble ◽  
Size Analysis ◽  
Physical Parameters ◽  
Mechanism Study ◽  
Soil Stabilizer ◽  
Typical Soil

In order to study the treatment mechanism of the ionic liquid soil stabilizer, a series tests were performed for a typical soil, the red-brown clay. The basic physical parameters of typical soil were conducted by variety of tests, including particle size analysis, crucial water content coefficient, loss on ignition, organic matter content, etc. Furthermore, the treatment mechanism of the ionic soil stabilizer was analyzed, involving PH, conductivity, plasma emission spectra, scanning electron microscopy, X-ray diffraction and BET test. The results indicate: Firstly, the ionic soil stabilizer is a sulfonated oleoresin with the features of water soluble, high conductivity and strongly acidic, which exchanged with cations adsorbed on the surface of clay particles to reduce the thickness of hydrated film and the electric double layer thickness. Secondly, it reduced the mutual repulsion energy between soil particles and made the flaky particles of clay minerals contact closely. Finally, it made the particles of clay be close to each other and gradually formed larger particles. Hence, the clay became denser. Therefore, the research provided a theoretical foundation and practical basis for the wide application of the ionic soil stabilizer in China's highway construction.

Solvent-free synthesis and properties of carboxymethyl starch fatty acid ester derivatives

2009 ◽  
Vol 63 (1) ◽  
Author(s):  
Viera Mazíková ◽  
Iva Sroková ◽  
Anna Ebringerová
Keyword(s):  
Fatty Acid ◽  
Methyl Esters ◽  
Solvent Free ◽  
Water Soluble ◽  
Polymeric Surfactants ◽  
Acid Complex ◽  
Carboxymethyl Starch ◽  
Solvent Free Conditions ◽  
Structural Surface ◽  
Solvent Free Synthesis

AbstractWater-soluble, partially hydrophobized polysaccharides have become attractive due to their potential to act as polymeric surfactants. From carboxymethyl starch (CMS), water-soluble polymeric surfactants were prepared by esterification using two unconvential methods based on (A) a reaction with mixed anhydrides and (B) with methyl laureate (MELA) and methyl esters of the fatty acid complex of rape seed oil (MERO) under ‘solvent-free’ conditions. The obtained CMS derivatives were characterized by structural, surface-active and surfactant performance properties. Esterification using method B was successful in contrast to method A which yielded derivatives with a very low extent of esterification. Although the derivatives reduced the surface tension moderately, they exhibited remarkable emulsifying properties. The performance tests indicated good washing power and antiredeposition efficiency. The results suggest that suitable polymeric surfactants can be prepared by the unconventional esterification method B using both acylation agents. The preparations might substitute the expensive and invasive industrially applied conventional methods.

scholarly journals Ion Mobility Spectrometry-Mass Spectrometry (IMS-MS) for on- and off-line analysis of atmospheric gas and aerosol species

2016 ◽  
Author(s):  
Jordan E. Krechmer ◽  
Michael Groessl ◽  
Xuan Zhang ◽  
Heikki Junninen ◽  
Paola Massoli ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Ion Mobility Spectrometry ◽  
Ion Mobility ◽  
Measurement Techniques ◽  
Molecular Ions ◽  
Molecular Structures ◽  
Water Soluble ◽  
Oxidation Products ◽  
Time Resolved ◽  
Organic Species

Abstract. Measurement techniques that provide molecular-level information are needed to elucidate the multi-phase processes that produce secondary organic aerosol (SOA) species in the atmosphere. Here we demonstrate the application of ion mobility spectrometry-mass spectrometry (IMS-MS) to the simultaneous characterization of the elemental composition and molecular structures of organic species in the gas and particulate phases. Molecular ions of gas-phase organic species are measured online with IMS-MS after ionization with a custom build nitrate chemical ionization (CI) source. This CI-IMS-MS technique is used to obtain time-resolved measurements (5 min) of highly oxidized organic molecules during the 2013 Southern Oxidant and Aerosol Study (SOAS) ambient field campaign in the forested SE US. The ambient IMS-MS signals are consistent with laboratory IMS-MS spectra obtained from single-component carboxylic acids and multicomponent mixtures of isoprene and monoterpene oxidation products. Mass-mobility correlations in the 2-dimensional IMS-MS space provide a means of identifying ions with similar molecular structures within complex mass spectra and are used to separate and identify monoterpene oxidation products in the ambient data that are produced from different chemical pathways. Water-soluble organic carbon (WSOC) constituents of fine aerosol particles that are not resolvable with standard analytical separation methods, such as liquid chromatography (LC), are shown to be separable with IMS-MS coupled to an electrospray ionization (ESI) source. The capability to use ion mobility to differentiate between isomers is demonstrated for organosulfates derived from the reactive uptake of isomers of isoprene epoxydiols (IEPOX) onto wet acidic sulfate aerosol. Controlled fragmentation of precursor ions by collisional dissociation (CID) in the transfer region between the IMS and the MS is used to validate MS peak assignments, elucidate structures of oligomers, and confirm the presence of the organosulfate functional group.

scholarly journals Molecular Distributions of Soluble Oxidation Products from Coals Characterized by Mass Spectrometers

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Xing Fan ◽  
Fei Wang
Keyword(s):  
Mass Spectrometry ◽  
Direct Analysis ◽  
Water Soluble ◽  
Oxidation Products ◽  
Gas Chromatography Mass Spectrometry ◽  
Mass Spectrometers ◽  
Polycarboxylic Acids ◽  
Alkanoic Acids ◽  
Carboxylic Groups ◽  
Soluble Species

Oxidation of three coals with rank from lignite to anthracite in NaOCl aqueous solution was investigated in this study. The oxidation products were characterized by using gas chromatography/mass spectrometry and direct analysis in real-time mass spectrometry. The results showed that most of organic compounds in coals were converted into water-soluble species under mild conditions, even the anthracite. Benzene polycarboxylic acids (BPCAs) and chloro-substituted alkanoic acids (CSAAs) were major products from the reactions. The products from lower rank coals consist of considerable CSAAs and most products from high rank coals are BPCAs. As coal rank increases, the yield of BPCAs with more carboxylic groups increases.

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