scholarly journals Direct synthesis of dimethyl carbonate and propylene glycol using potassium bicarbonate as catalyst in supercritical CO2

2015 ◽  
Vol 17 (1) ◽  
pp. 62-65 ◽  
Author(s):  
Yicun Wen ◽  
Rui Zhang ◽  
Yu Cang ◽  
Jianchao Zhang ◽  
Lixiao Liu ◽  
...  
Keyword(s):  
Propylene Glycol ◽  
Propylene Oxide ◽  
Large Scale ◽  
Dimethyl Carbonate ◽  
Direct Synthesis ◽  
Potassium Bicarbonate ◽  
One Pot ◽  
Optimized Conditions ◽  
First Time ◽  
By Products

Abstract The improved one-pot synthesis of dimethyl carbonate and propylene glycol from propylene oxide, supercritical carbon dioxide, and methanol with potassium bicarbonate as the catalyst has been reported in this paper. As far as we know, it is the first time to use potassium bicarbonate only as the catalyst in the production process which is simple and cheap. Satisfactory conversion rate of propylene oxide and yield of the products could be achieved at the optimized conditions with quite a small amount of by-products. Our new method offers an attractive choice for the production of dimethyl carbonate in large-scale industry efficiently and environmental friendly.

scholarly journals Conversion of Fructose to HMF in a Continuous Fixed Bed Reactor with Outstanding Selectivity

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1802 ◽  
Author(s):  
Eric Weingart ◽  
Sarah Tschirner ◽  
Linda Teevs ◽  
Ulf Prüße
Keyword(s):  
Large Scale ◽  
Continuous Process ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Water Addition ◽  
Batch Systems ◽  
Formation Conditions ◽  
High Yields ◽  
Optimized Conditions ◽  
By Products

5-Hydroxymethylfurfural (HMF) is a very promising component for bio-based plastics. Efficient synthesis of HMF from biomass is still challenging because of fast degradation of HMF to by-products under formation conditions. Therefore, different studies, conducted mainly in monophasic and biphasic batch systems with and without water addition have been published and are still under investigation. However, to produce HMF at a large scale, a continuous process is preferable. Until now, only a few studies have been published in this context. In this work, it is shown that fluorous alcohol hexafluoroisopropanol (HFIP) can act as superior reaction solvent for HMF synthesis from fructose in a fixed bed reactor. Very high yields of 76% HMF can be achieved in this system under optimized conditions, whilst the catalyst is very stable over several days. Such high yields are only described elsewhere with high boiling reaction solvents like dimethylsulfoxide (DMSO), whereas HFIP with a boiling point of 58 °C is very easy to separate from HMF.

Einfache photochemische Synthese von Benzylphosphanen / Facile Photochemical Synthesis of Benzylphosphines

1994 ◽  
Vol 49 (12) ◽  
pp. 1606-1614 ◽  
Author(s):  
Gerhard Müller ◽  
Martin Waldkircher ◽  
Martin Winkler
Keyword(s):  
Photochemical Reaction ◽  
Large Scale ◽  
Photochemical Synthesis ◽  
Product Selectivity ◽  
One Pot ◽  
Good Product ◽  
Consecutive Reactions ◽  
Soxhlet Apparatus ◽  
Short Period ◽  
By Products

Facile large-scale synthesis of the benzyl-dibromo-phosphines RPBr2 (R = C6H5CH2, 3,5-Me2C6H3CH2, 2-BrC6H4CH2) is accomplished by the photochemical reaction of toluene, mesitylene, and 2-bromotoluene, respectively, with PBr3 in the absence of solvent. If the reactions are carried out up to 50% completion the amount of by-products formed is remark­ ably low, rarely exceeding 10% of the total amount of products formed. The selectivity of the photoreaction may be improved up to 98% if it is carried out in a modified Soxhlet apparatus which allows the predominant irradiation of only the starting materials. The appar­ ent limitations imposed by the low turnovers required to achieve good product selectivity are by far outweighed by the large amounts of desired products formed in a short period of time and by the easy recovery of unreacted starting material by distillation. Thus in the case of 2-BrC6H4CH2PBr2, in a typical run 94 g (261 mmol) of product may be isolated after 2.5 h of irradiation of 970 mmol of 2-BrC6H5CH3 and 1.39 mol of PBr3. In this case the turnover is 32%. the isolated yield 27%, and the by-product 2-methylphenyl-dibromo-phosphine only amounts to less than 2%. The benzyl-dibromo-phosphines are easily methylated with two equivalents of MeMgCl to give the respective benzyl-dimethyl-phosphines in 79-93% yield. Tertiary benzylphosphines MePRR′ (R = 2-BrC6H4CH2, R′ = Me3SiCH2; R = R′ = 2-BrC6H4CH2) are obtained in easy one-pot syntheses by consecutive reactions of 2-BrC6H4CH2PBr2 with Me3SiCH2MgCl and MeMgCl, and with 2-BrC6H4CH2MgBr and MeMgCl, respectively.

One-pot synthesis of dimethyl carbonate and glycols from supercritical CO2, ethylene oxide or propylene oxide, and methanol

2004 ◽  
Vol 263 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Yanhong Chang ◽  
Tao Jiang ◽  
Buxing Han ◽  
Zhimin Liu ◽  
Weize Wu ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Propylene Oxide ◽  
Supercritical Co2 ◽  
Dimethyl Carbonate ◽  
One Pot ◽  
One Pot Synthesis

An Improved One-Pot Synthesis of Dimethyl Carbonate from Propylene Oxide, CO2 and Methanol

2011 ◽  
Vol 35 (11) ◽  
pp. 654-656 ◽  
Author(s):  
Bin Fan ◽  
Bo Qu ◽  
Qingchuan Chen ◽  
Yicun Wen ◽  
Liang Cai ◽  
...  
Keyword(s):  
Propylene Oxide ◽  
Dimethyl Carbonate ◽  
One Pot ◽  
One Pot Synthesis

Synthesis of [18F]FAZA Using Nosyl and Iodo Precursors for Nucleophilic Radiofluorination

2019 ◽  
Vol 12 (1) ◽  
pp. 49-57
Author(s):  
William Sun ◽  
Cheryl Falzon ◽  
Ebrahim Naimi ◽  
Ali Akbari ◽  
Leonard I. Wiebe ◽  
...  
Keyword(s):  
Large Scale ◽  
Side Reactions ◽  
Automated Synthesis ◽  
Complex Reaction ◽  
Chemical Structures ◽  
Standardized Protocol ◽  
High Yields ◽  
Automated Procedures ◽  
Optimized Conditions ◽  
By Products

Background: 1-&#945;-D-(5-Deoxy-5-[18F]fluoroarabinofuranosyl)-2-nitroimidazole ([18F]FAZA) is manufactured by nucleophilic radiofluorination of 1-&#945;-D-(2’,3’-di-O-acetyl-5’-O-toluenesulfonylarabinofuranosyl)- 2-nitroimidazole (DiAcTosAZA) and alkaline deprotection to afford [18F]FAZA. High yields (>60%) under optimized conditions frequently revert to low yields (<20%) in large scale, automated syntheses. Competing side reactions and concomitant complex reaction mixtures contribute to substantial loss of product during HPLC clean-up. Objective: To develop alternative precursors for facile routine clinical manufacture of [18F]FAZA that are compatible with current equipment and automated procedures. Methods: Two new precursors, 1-&#945;-D-(2’,3’-di-O-acetyl-5’-O-(4-nitrobenzene)sulfonyl-arabinofuranosyl)-2- nitroimidazole (DiAcNosAZA) and 1-&#945;-D-(2’,3’-di-O-acetyl-5’-iodo-arabinofuranosyl)-2-nitroimidazole (DiAcIAZA), were synthesized from commercially-available 1-&#945;-D-arabinofuranosyl-2-nitroimidazole (AZA). A commercial automated synthesis unit (ASU) was used to condition F-18 for anhydrous radiofluorination, and to radiofluorinate DiAcNosAZA and DiAcIAZA using the local standardized protocol to manufacture [18F]FAZA from AcTosAZA. Results: DiAcNosAZA was synthesized via two pathways, in recovered yields of 29% and 40%, respectively. The nosylation of 1-&#945;-D-(2’,3’-di-O-acetyl-arabinofuranosyl)-2-nitroimidazole (DiAcAZA) featured a strong competing reaction that afforded 1-&#945;-D-(2’,3’-di-O-acetyl-5’-chloro-arabinofuranosyl)-2- nitroimidazole (DiAcClAZA) in 55% yield. Radiofluorination yields were better from DiAcNosAZA and DiAcIAZA than from DiAcTosAZA, and the presence of fewer side products afforded higher purity [18F]FAZA preparations. Several radioactive and non-radioactive by products of radiofluorination were assigned tentative chemical structures based on co-chromatography with authentic reference compounds. Conclusion: DiAcClAZA, a major side-product in the preparation of DiAcNosAZA, and its deprotected analogue (ClAZA), are unproven hypoxic tissue radiosensitizers. DiAcNosAZA and DiAcIAZA provided good radiofluorination yields in comparison to AcTosAZA and could become preferred [18F]FAZA precursors if the cleaner reactions can be exploited to bypass HPLC purification.

Acid-Base Bifunctional Metal-Organic Frameworks: Green Synthesis and Application in One-Pot Glucose to 5-HMF Conversion

NANO ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. 1850132 ◽  
Author(s):  
Yunlei Zhang ◽  
Pei Jin ◽  
Minjia Meng ◽  
Lin Gao ◽  
Meng Liu ◽  
...  
Keyword(s):  
Active Sites ◽  
Large Scale ◽  
Direct Synthesis ◽  
Metal Organic Frameworks ◽  
Acid Base ◽  
One Pot ◽  
Ring Opening Reaction ◽  
Metal Organic ◽  
Base Strength ◽  
Viable Approach

The direct synthesis of metal-organic frameworks (MOFs) with acidic and basic active sites is challenging due to the introduction of functional groups by post-functionalization method often jeopardize the framework integrity. Herein, we report the direct synthesis of acid-base bi-functional MOFs with tuning acid-base strength. Employing modulated hydrothermal (MHT) approach, microporous MOFs named UiO-66-NH2 was prepared. Through the ring-opening reaction of 1,3-propanesultone with amino group, UiO-66-NH2-SO3H-type catalysts can be obtained. The synthesized catalysts were well characterized and their catalytic performances were evaluated in one-pot glucose to 5-HMF conversion. Results revealed the acid-base bi-functional catalyst possessed high activity and excellent stability. This work provides a general and economically viable approach for the large-scale synthesis of acid-base bi-functional MOFs for their potential use in catalysis field.

scholarly journals Lignin Phenol Formaldehyde Resins Synthesised Using South African Spent Pulping Liquor

2021 ◽  
Author(s):  
Chelaine Maree ◽  
Johann F. Görgens ◽  
Luvuyo Tyhoda
Keyword(s):  
South African ◽  
Phenol Formaldehyde ◽  
One Pot ◽  
Substitution Level ◽  
Central Composite Designs ◽  
Soda Lignin ◽  
First Time ◽  
Composite Designs ◽  
Central Composite ◽  
By Products

Abstract Purpose The current study investigated to which extent phenol could be replaced by lignins to produce lignin phenol formaldehyde (LPF) resins, utilising soda lignin and sodium lignosulphonate as by-products from the South African pulping industry.Method The lignins were characterised and soda lignin indicated the highest reactivity. It was therefore utilised to produce LPF resins at 60%, 80%, and 100% phenol substitution, using central composite designs to maximise the adhesive strength. A one-pot method allowing direct transition from phenolation to resin synthesis was used for the first time with a pulping lignin at 60% and 80% substitution.Results Plywood made with LPF60, LPF80, and LPF100 resins attained their highest shear strengths of 0.786, 1.09, and 0.987 MPa, respectively, which adhered to the GB/T 14732-2013 standard (≥ 0.7 MPa). A substitution level of 68% produced the highest shear strength of 1.11 MPa. High-density particleboard made with this LPF68 resin gave a MOR and MOE of 40 and 3209 MPa, respectively, adhering to the ANSI A208.1 requirements. Thickness swelling and water absorption was 13.5% and 37.2%, respectively.Conclusion The soda-lignin isolated by precipitation from sugarcane bagasse pulping liquor is the first industrial lignin shown to produce LPF100 resins adhering to standard requirements, without modification or additives.

scholarly journals A Zn-MOF-Catalyzed Terpolymerization of Propylene Oxide, CO2, and β-butyrolactone

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 393 ◽  
Author(s):  
Sudakar Padmanaban ◽  
Sivanesan Dharmalingam ◽  
Sungho Yoon
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Propylene Oxide ◽  
One Pot ◽  
The One ◽  
First Time ◽  
Poly Carbonate ◽  
Thermal Stability Of

The terpolymerization of propylene oxide (PO), CO2, and a lactone is one of the prominent sustainable procedures for synthesizing thermoplastic materials at an industrial scale. Herein, the one-pot terpolymerization of PO, CO2, and β-butyrolactone (BBL) was achieved for the first time using a heterogeneous nano-sized catalyst: zinc glutarate (ZnGA-20). The reactivity of both PO and BBL increased with the CO2 pressure, and the polyester content of the terpolymer poly (carbonate-co-ester) could be tuned by controlling the infeed ratio of PO to BBL. When the polyester content increased, the thermal stability of the polymers increased, whereas the glass transition temperature (Tg) decreased.

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