- Biomass-derived dibasic acids to diesters with inorganic ligand-supported catalyst: synthesis, optimization, characterization
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Several attempts have been made to obtain aliphatic dicarboxylic diesters from esterification reaction to develop the biomass-derived platform molecules and green manufacturing processes. In this paper, Na3(H2O)6[AlMo6O18(OH)6], an Anderson-type polyoxometalate, firstly, was reported as a catalyst for diester synthesis from dicarboxylic acid to diester which showed an well productivity and selectivity characterized by 1H and 13C. Response surface methodology (RSM) integrated with the desirability function approach was used to determine the best operative conditions, and the optimal reaction parameters for maximum dipropyl succinate yield (77 ± 2.5%) were identified as 1.19?mol.% catalyst loading, 4.9:1 propanol/succinic acid ratio, 113?°C, and 9.6?h. Three batches of tests were carried for catalyst recycling with 78–75% yield even after 6 cycles of esterification. In addition, the substrate carbon chain was increased for investigation of substrate scope achieving satisfactory results and all products were characterized by 1H and 13C nuclear magnetic resonance spectroscopy.
- Chen, Zhe,Han, Sheng,Lu, Deli,Xu, Yumeng
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- Direct synthesis of adipic acid esters via palladium-catalyzed carbonylation of 1,3-dienes
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The direct carbonylation of 1,3-butadiene offers the potential for a more cost-efficient and environmentally benign route to industrially important adipic acid derivatives. However, owing to the complex reaction network of regioisomeric carbonylation and isomerization pathways, a selective practical catalyst for this process has thus far proven elusive. Here, we report the design of a pyridyl-substituted bidentate phosphine ligand (HeMaRaphos) that, upon coordination to palladium, catalyzes adipate diester formation from 1,3-butadiene, carbon monoxide, and butanol with 97% selectivity and 100% atom-economy under industrially viable and scalable conditions (turnover number > 60,000). This catalyst system also affords access to a variety of other di- and triesters from 1,2- and 1,3-dienes.
- Yang, Ji,Liu, Jiawang,Neumann, Helfried,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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p. 1514 - 1517
(2020/01/08)
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- Exceptionally active and reusable nanobiocatalyst comprising lipase non-covalently immobilized on multi-wall carbon nanotubes for the synthesis of diester plasticizers
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A new method for the synthesis of dicarboxylic acid esters in the presence of a new heterogeneous nanobiocatalyst consisting of Candida antarctica lipase B immobilized on multi-walled carbon nanotubes (MWCNTs) has been developed. Selection and characterization of the support for Candida antarctica lipase B (CALB) was initially performed. Pristine and modified MWCNTs of different geometries, morphologies and surface/core modifications were tested as a lipase carrier and determining that the CheapTubes MWCNTs nanobiocatalyst with a 15.7 wt.% CALB loading was the most active nanobiocatalyst. The model reaction of succinic acid with n-butanol was carried out with a 4-molar excess of alcohol and 150 mg of nanobiocatalyst per 1 mmol of succinic acid at 45 °C in cyclohexane. The di-n-butyl succinate was obtained with 95% yield after 3 h. The activities of the new nanobiocatalysts were compared with the benchmark Novozyme-435 and other acidic catalysts. Recycling studies demonstrated the possibility of utilizing the most active MWCNTs-lipase biocatalyst six times without any significant loss of activity. The main advantage of this study is the superior activity of the new nanobiocatalyst, which resulted in a significant reduction of reaction times as compared to those reported in the literature.
- Szelwicka, Anna,Boncel, S?awomir,Jurczyk, Sebastian,Chrobok, Anna
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- Micro-flow nanocatalysis: synergic effect of TfOH@SPIONs and micro-flow technology as an efficient and robust catalytic system for the synthesis of plasticizers
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The combination of continuous flow technology with immobilizing of only 0.13?mol% of triflic acid (TfOH) on silica-encapsulated superparamagnetic iron oxide nanoparticles (SPIONs) under solvent-free conditions successfully provided a powerful, efficient, and eco-friendly route for the synthesis of plasticizers. The turnover frequency value in micro-flow conditions varied in the range of 948.7 to 7384.6 h?1 compared to 403.8 to 3099 h?1 for in-flask. This technique works efficiently, encouraging future applications of micro-flow nano-catalysis in green chemistry.
- Tashi, Maryam,Shafiee, Behnaz,Sakamaki, Yoshie,Hu, Ji-Yun,Heidrick, Zachary,Khosropour, Ahmad R.,Beyzavi, M. Hassan
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p. 37835 - 37840
(2018/11/26)
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- The synthesis of di-carboxylate esters using continuous flow vortex fluidics
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A vortex fluidic device (VFD) is effective in mediating the synthesis of di-esters at room temperature. Processing under ambient conditions allows for a simple and efficient synthesis, whilst operating under continuous flow addresses scalability. The rotational speed of the sample tube and the flow rate were critical variables during reaction optimization, and this relates to the behaviour of the fluid flow at a molecular level. Whilst at specific rotational speeds the tube imparts a vibrational response into the fluid flow, the flow rate dictates residence time and the ability to maintain high levels of shear stress. The combination of mechanically induced vibrations, rapid micromixing, high levels of shear stress and water evaporation results in yields up to 90% for 3.25 minutes or less residence time. These results are key for devising greener and more efficient processes both mediated by the VFD and other continuous flow platforms.
- Britton, Joshua,Dalziel, Stuart B.,Raston, Colin L.
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p. 2193 - 2200
(2016/04/19)
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- Synthesis of carboxylic acid esters in the presence of micro- and mesoporous aluminosilicates
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The catalytic properties of zeolites HY, HBeta, and HZSM-12 and of mesoporous amorphous aluminosilicate in liquid-phase esterification of aliphatic (monobasic C1-C18, dibasic C6, C10) and aromatic (benzoic, trimellitic, phthalic) carboxylic acids with butanol were studied. Zeolite HBeta appeared to be the most active catalyst. Procedures were developed for preparing esters in the presence of zeolitic catalyst HBeta, ensuring 100% selectivity of ester formation at 90-98% conversion of the acid.
- Grigor'Eva,Suleimanova,Agliullin,Kutepov
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p. 773 - 779
(2015/01/30)
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- NOVEL FORMULATION OF DEHYDRATED LIPID VESICLES FOR CONTROLLED RELEASE OF ACTIVE PHARMACEUTICAL INGREDIENT VIA INHALATION
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A new formulation of dehydrated lipid vesicles employs a vesicle preserver and permits the control of release and delivery of active pharmaceutical ingredients into the respiratory system for treatment in particular of asthma. The typical formulation provides controlled release of the active pharmaceutical ingredient from 0% to 100% from 0 to 72 hours after inhalation, changes the systemic administration to topical administration, allows prolonged therapeutic period for one administration, increased stability, with reduced dose, reduced systemic side effects, reduced toxicity.
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- Polyaldimines
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Two component PUR composition can be obtained when a first component (A) is prepared having a PUR prepolymer with isocyanate groups and an aromatic polyisocyanate, a polyol, and a polyaldimine, obtainable from a polyamine with primary aliphatic amino groups and an aldehyde, and a second component (B). Two component PUR composition having high early strength can be obtained when a first component (A) is prepared having a PUR prepolymer with isocyanate groups and an aromatic polyisocyanate, a polyol, and a polyaldimine, obtainable from a polyamine with primary aliphatic amino groups and an aldehyde, which has no C-H groups in the alpha-position to the carbonyl group, and a second component (B) containing water bonded to a carrier material. Independent claims are included for: (1) a process for preparation of a two-component PUR composition involving a step for preparation of a polyaldimine from an aldehyde and a polyamine; (2) a process for mixing a two-component PUR composition where the mixing ratio of the first component A to the second component B is selected so that the ratio of equivalent water (sic) to equivalent aldimine groups is 0.5-10.0, especially 1.0-5.0; and (3) a process for application of a two-component PUR composition involving the steps: mixing of A and B, contacting solid body surface (sic) with the mixed PUR composition, and curing of the mixed PUR composition.
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Page/Page column 8
(2008/06/13)
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- Evolution of products in the combustion of scrap tires in a horizontal, laboratory scale reactor
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A horizontal laboratory reactor was used to study the evolution of byproducts from the combustion of scrap tires at five nominal temperatures (ranging from 650 to 1050 °C) and different oxygen:sample ratios A model was used to calculate the bulk air ratio (λ), and the oxygen consumption was discussed considering this ratio λ. More than 100 volatile and semivolatile compounds were identified and quantified by gas chromatography mass spectrometry, plotting their yields vs the bulk air ratio and temperature. Five different behaviors considering the bulk air ratio and the temperature were identified.
- Fullana,Font,Conesa,Blasco
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p. 2092 - 2099
(2007/10/03)
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- Selective monoesterification of dicarboxylic acids catalysed by ion-exchange resins
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Symmetrical dicarboxylic acids with 4-14 carbon atoms gave selectively the corresponding monoesters in high yields in the transesterification catalysed by strongly acidic ion-exchange resins in ester-hydrocarbon mixtures. It was found that the rate of the esterification of the dicarboxylic acids is much higher than that of the monocarboxylic acids formed. This result can explain the high selectivity for the monoester formation and can also be explained by the existence of an aqueous layer on the surface of the resins. This method of selective esterification is quite simple and practical. The Royal Society of Chemistry 1999.
- Nishiguchi, Takeshi,Ishii, Yasuhiro,Fujisaki, Shizuo
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p. 3023 - 3027
(2007/10/03)
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- Convenient selective monoesterification of α, ω-dicarboxylic acids catalyzed by ion-exchange resins
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Symmetric dicarboxylic acids, ranging from pentanedioic acid to tetradecanedioic acid, gave selectively the corresponding monoesters in high yields in the transesterification catalyzed by strongly acidic ion-exchange resins in ester/octane mixtures.
- Saitoh, Masahiko,Fujisaki, Shizuo,Ishii, Yasuhiro,Nishiguchi, Takeshi
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p. 6733 - 6736
(2007/10/03)
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- Cosmetic composition
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A composition suitable for topical application to mammalian skin or hair for inducing, maintaining or increasing hair growth comprises: (i) a first chemical inhibitor chosen from proteoglycanase inhibitors, glycosaminoglycanase inhibitors, glycosaminoglycan chain cellular uptake inhibitors or mixtures thereof; and (ii) a cosmetically acceptable vehicle for the chemical inhibitor; provided that when the first chemical inhibitor is a weak inhibitor, such that a 1 mM aqueous solution of the inhibitor reduces proteoglycanase activity, glycosaminoglycanase activity or cellular uptake of glycosaminoglycan chains, by from 5 to 50%, in accordance with at least one of the assay tests as herein described, then there is also present in the composition a second chemical inhibitor and/or an activity enhancer. When minoxidil is the sole chemical inhibitor, then the activity enhancer is a penetration enhancer chosen from a limited number of materials, including certain esters and cationic polymers. The total amount of chemical inhibitor present in the composition is sufficient to increase hair growth in the rat, when said composition is applied topically thereto, by at least 10% more than that obtainable using a control composition from which the said inhibitors have been omitted.
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- SELECTIVE MONOETHERIFICATION AND MONOESTERIFICATION OF DIOLS AND DIACIDS UNDER PHASE-TRANSFER CONDITIONS
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Research on the selectivity of etherification reactions of diols and esterification reactions of diacids by alkyl halides under phase-transfer catalysis has shown that under such conditions, selectivity of monoetherification increases in the order prim sec tert diols, though overall yield of monoether decreases from sec to tert diols.Monoesterification of diacids was accomplished with a high degree of selectivity.Optimal extraction of diols and diacids was found to correspond in general to chain lengths of around 5 carbons.This could mean that the complex formed between the catalyst and the anion to react is stabilized for certain carbon lengths by inner solvation in virtue of its spatial conformation.
- Zerda, Jaime de la,Barak, Gabriela,Sasson, Yoel
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p. 1533 - 1536
(2007/10/02)
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