- An efficient method for the refinement of 1,3-methyleneglycerol via bridged acetal exchange and the synthesis of a symmetrically branched glycerol trimer
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Acid-catalyzed equilibrium of a mixture of 1,2- and 1,3-methyleneglycerol in 1,4-dioxane affords predominantly the 1,3-isomer via bridged acetal exchange. The minor 1,2-isomer is removed via sequential pivaloylation and tritylation to afford the desired 1,3-isomer in >99.5% purity. A symmetrically branched triglycerol is efficiently synthesized starting from the purified 1,3-isomer. Georg Thieme Verlag Stuttgart · New York.
- Hattori, Hatsuhiko,Matsushita, Tsuyoshi,Yoshitomi, Kohsuke,Katagiri, Ayato,Nemoto, Hisao
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- Glycerol acetalization with formaldehyde using water-tolerant solid acids
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The acid-catalyzed reaction of glycerol with aqueous formaldehyde was studied using various heterogeneous catalysts for the production of glycerol formal. Owing to the high amount of water involved in the reaction medium, three types of water-tolerant heterogeneous catalysts namely acid functionalized periodic mesoporous organosilicas (PMOs), zeolite ZSM-5 and a heteropoly compound Cs2.5H0.5PW12O40 as well as commercial catalyst Amberlyst-15 were used for glycerol acetalization. The activity of Cs2.5H0.5PW12O40 was found superior to that of the other catalysts and the glycerol conversion was over 70% within 60 min of reaction time. The effects of different parameters including temperature, feed composition and catalyst content, were studied as well. The distribution of the two glycerol formal isomers could be controlled by changing reaction parameters. Optimum reactive parameters were studied to control the distribution of the acetal isomers aiming to reach a high selectivity to the six-member ring isomer.
- Chen, Lin,Nohair, Bendaoud,Kaliaguine, Serge
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- Mesoporous Zr-SBA-16 catalysts for glycerol valorization processes: Towards biorenewable formulations
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Zr-containing SBA-16 materials were utilized in glycerol valorization for the production of esters (via reaction with levulinic acid) and glycerol formal (GF) via acetalisation with paraformaldehyde. The materials were found to be highly active and selective for the production of valuable compounds from glycerol using benign by design solventless protocols which employ mild reaction conditions. Certain materials were also found to be highly reusable and stable under the investigated conditions.
- Gonzalez-Arellano, Camino,Parra-Rodriguez, Leticia,Luque, Rafael
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Read Online
- Biomass alcoholysis method for petroleum-based plastic POM
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The invention discloses a biomass alcoholysis method for petroleum-based plastic POM. According to the method, simple biomass derivative alcohol and the petroleum-based plastic POM are allowed to generate a cyclic acetal product through dehydration condensation under catalytic conditions; low reaction cost and high added value are realized, and only water is byproduced and is easy to separate; and an obtained product has high added value, can be used for preparing organic solvents such as lignin and chromatographic analysis solvents, metal surface treatment agents or medical intermediates and monomers, realizes green, efficient and low-cost recovery, and has a high practical application value.
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Paragraph 0030-0052
(2021/05/01)
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- Interaction of triols with formaldehyde and acetone: Experimental and theoretical study
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Experimental and theoretical aspects of the condensation of glycerol and its homologs (1,2,3- and 1,2,4-butanetriols) with formaldehyde and acetone are studied under conditions of acid catalysis. Calculation of the thermodynamic parameters of the resulting products by the composite method CBS-QB3 shows that the six-membered heterocycles, the products of the interaction of triols with formaldehyde, are thermodynamically more stable than the five-membered acetals, while the reaction of the same triols with acetone is preferable for the formation of the five-membered acetals. This is due to the fact that the regioselectivity of the studied reactions is determined by the structural features and reactivity of the carbocations formed in a condensed medium during the course of the reaction. According to the theoretical data obtained experimentally, during the condensation of glycerol and 1,2,4-butanetriol with formaldehyde in the most stable form of the six-membered cyclic carbocation, intramolecular hydrogen bonding and anomeric stabilization due to the axially oriented hydroxyl group take place. As a result, cation 1b–1 is 1.2–1.6 kJ/mol more stable than its five-membered isomers (1a–1 and 1b–2). It leads to the predominant formation of 1,3-dioxane (3b). However, upon condensation of butanetriol-1,2,3 with formaldehyde, the intermediate cation 4a–1 turns out to be significantly more stable than the other isomers due to the strong intramolecular hydrogen bond in the six-membered ring with the participation of the hydroxyl group of the substituent and the hydroxyl group of the cationic center, leading to the predominant formation of the dioxolane 6a.
- Sultanova, Rimma,Borisevich, Sophia,Raskil'dina, Gulnara,Borisova, Julianna,Baykova, Irina,Spirikhin, Leonid,Khursan, Sergey,Zlotsky, Simon
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p. 1144 - 1151
(2020/02/25)
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- A bifunctional catalyst based on Nb and v oxides over alumina: Oxidative cleavage of crude glycerol to green formic acid
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A bimetallic vanadium and niobium oxide catalyst using alumina as support was developed for the conversion of crude glycerol from biodiesel production into formic acid. The high dispersion of the active oxide phase combined with the presence of acid and redox active centers resulted in a high glycerol conversion (>90% for 25 h) with a good selectivity for formic acid (～55%). This process is the first example of a heterogeneous liquid-phase process for the conversion of crude glycerol to formic acid, which is an important chemical intermediate currently derived from petroleum feedstock.
- Chagas, Poliane,Figueiredo, Marcio P.,Hensen, Emiel J. M.,Oliveira, Henrique S.,Oliveira, Luiz Carlos A.,Sangiorge, Daniel L.,Siqueira, Kisla P. F.
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p. 8538 - 8544
(2020/06/19)
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- Method for preparing glycerol benzaldehyde
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The invention discloses a method for preparing glycerol benzaldehyde. Metal zinc modified strong acid cation exchange resin is used as a catalyst for synthesizing the glycerol benzaldehyde. Owing to modification of metal zinc, the strong acid cation exchange resin has the function of activating aldehydic carbonyl, glycerol conversion rate reaches up to 95% or more, and product yield is 88% or more.
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Paragraph 0032; 0033
(2019/04/17)
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- Method for preparing glycerolformal
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The invention discloses a method for preparing glycerolformal. According to the invention, SO42-/Fe2O3-CNTS super acid is used as a catalyst for compounding glycerolformal, so that the method has theadvantages that reaction temperature is low, catalyst activity is high, no new water-carrying agent is brought, yield of reaction products is 95% or above and hexatomic ring products are high in proportion.
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Paragraph 0029-0034
(2019/04/11)
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- Glycerolformal industrial production method
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The invention discloses a glycerolformal industrial production method. The glycerolformal industrial production method achieves synthesis of glycerolformal by taking SO42-/ZrO2-CNTS (carbon nanotubes)super acids as catalysts. The glycerolformal industrial production method is low in reaction temperature, high in activity of catalysts, free from introduction of new water-carrying agent and short in reaction time; the products achieve a yield of higher than 92% and a high proportional ratio of hexatomic ring products.
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Paragraph 0029-0032
(2019/05/22)
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- Highly Efficient Glycerol Acetalization over Supported Heteropoly Acid Catalysts
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The acetalization of glycerol with acetone to yield solketal was catalyzed by Cs2.5H0.5PW12O40 (Cs2.5) supported on mesoporous silica under mild conditions. It gave a high glycerol conversion and selectivity to the targeted product even at room temperature (23 °C). We studied the use of both bulk and supported Cs2.5 as catalysts in another highly efficient glycerol acetalization reaction with paraformaldehyde, which gave much higher activity than with formaldehyde solution. For the reaction with acetone, the supported Cs2.5 showed a higher activity than the bulk material because of the high surface area of the mesoporous support. Interestingly, the supported Cs2.5 gave a lower conversion than the bulk for the reaction with paraformaldehyde. This is probably because of the high viscosity of the reaction system with the solid reagent paraformaldehyde. Overall, there is a complex relationship between catalyst, reaction conditions, which include the molar ratio of reactants and temperature, reaction mechanism and thermodynamics that affects the achieved activity and byproduct formation. A discussion about these interactions is included for each reaction.
- Chen, Lin,Nohair, Bendaoud,Zhao, Dongyuan,Kaliaguine, Serge
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p. 1918 - 1925
(2018/03/28)
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- Preparation method of cyclic acetal
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The invention discloses a preparation method of cyclic acetal. The method is characterized in that long-chain polyhydroxy compounds and small-molecular aldehydes are used as the substrates, long-chain weak-polarity molecules are used as the solvent, and the aldehydes are condensed with the hydroxyl groups at two ends of the polyhydroxy compounds under the effect of a catalyst to form the intramolecular cyclic acetal. Compared with a traditional acetal preparation method, the method has the advantages that the property differences of the solvent, reactants and the substrates are utilized to allow the aldehydes to be easy to react with the hydroxyl groups, and the cyclic acetal proportion in the product is high; the conversion rate of the aldehyde compounds reaches above 80%, and the selectivity of the cyclic acetal can reach above 80%.
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Paragraph 0020; 0021; 0022; 0023; 0024; 0025; 0026-0029
(2017/08/29)
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- Catalytic behaviour of mesoporous metal phosphates in the gas-phase glycerol transformation
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The catalytic behaviour of mesoporous simple (M = Al, Fe, Co, Mn) and binary (Al/M; M = Fe,V,Ca; molar ratio Al/Fe = 50; Al/V = 2; Al/Ca = 1) metal phosphates, synthesized by an economical gelation method, in the gas-phase glycerol reaction at temperatures between 220 °C and 280 °C, has been investigated. The morphology, textural properties and the acidity by pyridine TPD, of the phosphates were also determined. The activity of the phosphates in the formation of the main reaction product (acrolein) depended not only on their acidity (mainly acid sites of weak-medium strength) but also on the redox sites and morphology exhibited. Thus, the aluminium-vanadium phosphate showed the highest value of yield to acrolein, 62% (equivalent to a productivity of 0.88 gACRgcath) at 280 °C, whereas the amorphous FePO4 and AlPO4 were appreciably more active than the rest of the simple phosphates, exhibiting a high crystalline character. The apparent activation energy values obtained for the acrolein formation ranged between 18 and 91 kJ/mol. Based on the identified products in this study, some possible reactions involved in the glycerol transformation have been suggested.
- Lopez-Pedrajas,Estevez,Navarro,Luna,Bautista
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- Zeolite-supported iron catalysts for allyl alcohol synthesis from glycerol
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Under most reaction conditions studied, acrolein is reported as the primary product in the conversion of glycerol over zeolites. In such processes, acrolein forms at relatively high yields, with negligible allyl alcohol selectivity. In this contribution, we report the development of ZSM5-supported iron catalysts, modified by rubidium deposition, as stable materials for production of allyl alcohol from glycerol. Our results demonstrate a reduced rate of formation of acrolein over modified catalysts. Both unmodified and modified catalysts were analysed by inductively coupled plasma optical emission spectrometry, nitrogen adsorption, scanning electron microscope, X-ray diffraction, ammonia temperature programmed desorption, X-ray photoelectron spectroscopy and ultraviolet-visible spectroscopy. These techniques revealed that differences in product distribution and catalyst performance are due to the combined effects of iron loading, catalyst acidity and changes in the porosity of the catalyst.
- Sánchez,Dlugogorski,Kennedy,Stockenhuber
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p. 130 - 142
(2015/11/24)
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- Synthesis, structure, and transformations of cyclic glycerol formals
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Glycerol reacts with paraformaldehyde to give a mixture of 4-hydroxymethyl-1,3-dioxolane and 5-hydroxy-1,3-dioxane. Some transformations (alkylation and replacement of the OH groups with the Cl atoms) of the synthesized compounds were performed. The differences in NMR and mass spectra of the corresponding 1,3-dioxolanes and 1,3-dioxanes were revealed and discussed.
- Raskildina,Valiev,Sultanova,Zlotsky
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p. 2095 - 2099
(2016/10/03)
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- Al-SBA-15 catalysed cross-esterification and acetalisation of biomass-derived platform chemicals
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Al-SBA-15 exhibited excellent catalytic activities in acid-catalysed glycerol transformation including esterification and acetalisation reactions. Quantitative conversion and good selectivities to mono- and diacetylglycerides could be obtained in the esterification of glycerol with levulinic acid. The catalyst also proved to be very effective in the acetalisation of glycerol with aldehydes and acetone, with an interesting selectivity switch from the 6-membered acetal (using paraformaldehyde as an aldehyde source) to a 5-membered acetal (when benzaldehyde or furfural was employed). Al-SBA-15 materials were also proved to be highly stable and reusable in most glycerol transformations under the investigated reaction conditions.
- Gonzalez-Arellano, Camino,Arancon, Rick A. D.,Luque, Rafael
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p. 4985 - 4993
(2015/01/08)
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- Selective glycerol transformations to high value-added products catalysed by aluminosilicate-supported iron oxide nanoparticles
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Conversion of glycerol to cyclic acetals (with paraformaldehyde, benzaldehyde, furfural and acetone) and to mono-, di- and triacetylglycerides (with levulinic acid) was investigated using a supported iron oxide nanoparticle system of a mesoporous aluminosilicate heterogeneous catalyst (Fe/Al-SBA-15). The effect of various parameters on the reaction, temperature, mol% of catalyst or ratio of glycerol:substrate were studied. An optimization of the reaction conditions carried out with glycerol by means of experimental design methodology showed that a very high glycerol conversion (99%) and high combined selectivity toward di- and triacetylglycerides could be obtained under optimized conditions. All of the acetalisation reactions carried out at 100 °C also gave good to excellent conversions and selectivities to target products, illustrating the potential of Fe/Al-SBA-15 as a highly active, stable and reusable heterogeneous catalyst in glycerol acid-catalysed transformations.
- Gonzalez-Arellano, Camino,De, Sudipta,Luque, Rafael
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p. 4242 - 4249
(2015/01/09)
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- Synthesis and bactericidal activity of substituted cyclic acetals
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A series of substituted cyclic acetals were synthesized and tested for their bactericidal activity against bacteria strain Azospirillum brasilense Sp245.
- Tugarova,Kazakova,Kamnev,Zlotskii
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p. 1930 - 1933
(2015/02/02)
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- Green Acetylation of Solketal and Glycerol Formal by Heterogeneous Acid Catalysts to Form a Biodiesel Fuel Additive
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A glut of glycerol has formed from the increased production of biodiesel, with the potential to integrate the supply chain by using glycerol additives to improve biodiesel properties. Acetylated acetals show interesting cold flow and viscosity effects. Herein, a solventless heterogeneously catalyzed process for the acetylation of both solketal and glycerol formal to new products is demonstrated. The process is optimized by studying the effect of acetylating reagent (acetic acid and acetic anhydride), reagent molar ratios, and a variety of commercial solid acid catalysts (Amberlyst-15, zeolite Beta, K-10 Montmorillonite, and niobium phosphate) on the conversion and selectivities. High conversions (72–95 %) and selectivities (86–99 %) to the desired products results from using acetic anhydride as the acetylation reagent and a 1:1 molar ratio with all catalysts. Overall, there is a complex interplay between the solid catalyst, reagent ratio, and acetylating agent on the conversion, selectivities, and byproducts formed. The variations are discussed and explained in terms of reactivity, thermodynamics, and reaction mechanisms. An alternative and efficient approach to the formation of 100 % triacetin involves the ring-opening, acid-catalyzed acetylation from solketal or glycerol formal with excesses of acetic anhydride.
- Dodson, Jennifer R.,Leite, Thays d C. M.,S. Pontes, Nathália,Peres Pinto, Bianca,Mota, Claudio J. A.
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p. 2728 - 2734
(2016/12/23)
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- 1,2,3-Trimethoxypropane and glycerol ethers as bio-sourced solvents from glycerol: Synthesis by solvent-free phase-transfer catalysis and utilization as an alternative solvent in chemical transformations
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1,2,3-Trimethoxypropane (2), 1-alkoxy-2,3-dimethoxy-propanes, and 1-aryloxy-2,3-dimethoxypropanes were prepared in good yields and selectivity by solid-liquid phase-transfer catalysis in the presence of an inorganic base and an ammonium salt as the phase-transfer catalyst with no additional solvent. No heating was required, and the synthesis was easily performed under atmospheric pressure on a 150g scale. For the preparation of 2, the conversion of glycerol was complete and the selectivity for the expected glycerol trimethylether was above 95%. This product was utilized as a solvent in organic reactions such as transesterifications between glycerol and vegetable oil, organometallic reactions (Grignard- and Barbier-type reactions), carbon-carbon coupling reactions (Suzuki, Sonogashira, Heck), and in etherification reactions by dehydrogenative alkylation. The solvent showed interesting properties for the solubilization of polymers.
- Sutter, Marc,Dayoub, Wissam,Metay, Estelle,Raoul, Yann,Lemaire, Marc
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p. 2893 - 2904
(2013/10/21)
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- HIV PROTEASE INHIBITORS AND METHODS FOR USING
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Compounds that inhibit proteolytic enzymes of Human Immunodeficiency Virus (HIV) are described. Preparation of the inhibitors, pharmaceutical compositions containing them, and uses of the compounds or compositions for the treatment of HIV infections are also described.
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Page/Page column 27
(2011/06/10)
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- Gold catalysts and solid catalysts for biomass transformations: Valorization of glycerol and glycerol-water mixtures through formation of cyclic acetals
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The valorization of pure glycerol and glycerol in water has been achieved by reaction with aldehydes to form valuable acetals. While soluble PTSA is more active than solid Bronsted acids such as zeolites and resins when reacting with pure glycerol, the synthesis of a hydrophobic zeolite with the adequate ratio of polarity/acidity leads to a better catalyst when reacting with glycerol-water mixtures. Best results (up to 94% yield) were obtained with gold as Lewis acid catalysts under very mild reaction conditions. The preparation of a recoverable and reusable gold catalyst allows to achieve high turnover numbers.
- Ruiz, Violeta R.,Velty, Alexandra,Santos, Laura L.,Leyva-Perez, Antonio,Sabater, Maria J.,Iborra, Sara,Corma, Avelino
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scheme or table
p. 351 - 357
(2010/06/01)
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- Water-tolerant zeolite catalyst for the acetalisation of glycerol
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We studied the acid-catalysed reaction of glycerol with aqueous formaldehyde and acetone in absence of solvents and using heterogeneous catalysts. The reactivity of acetone was usually higher than formaldehyde and the glycerol conversion was over 90% within 40 min of reaction time for all the heterogeneous acid catalysts studied. With aqueous formaldehyde solution, the glycerol conversion was within 60 to 80%, depending upon the acid catalyst used (Amberlyst-15, K-10 montmorillonite, p-toluene-sulfonic acid), due to the high amount of water in the reaction medium, which shifts the equilibrium and weakens the acid sites. However, the use of zeolite Beta, with Si/Al ratio of 16, leads to a conversion of over 95% within 60 min of reaction time. The hydrophobic character of the zeolite, due to the high silicon content, prevents the diffusion of the water to the interior of the pore, preserving the strength of the acid sites. In addition, the water formed during the acetalisation is expelled off from the pore environment, impairing the reverse reaction, and avoiding the use of hazard solvents, commonly employed to distil off the water formed.
- Da Silva, Carolina X. A.,Gonalves, Valter L. C.,Mota, Claudio J. A.
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body text
p. 38 - 41
(2010/04/22)
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- Flexible cyclic ethers/polyethers as novel P2-ligands for HIV-1 protease inhibitors: Design, synthesis, biological evaluation, and protein-ligand X-ray studies
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We report the design, synthesis, and biological evaluation of a series of novel HIV-1 protease inhibitors. The inhibitors incorporate stereochemically defined flexible cyclic ethers/polyethers as high affinity P2-ligands. Inhibitors containing small ring 1,3-dioxacycloalkanes have shown potent enzyme inhibitory and antiviral activity. Inhibitors 3d and 3h are the most active inhibitors. Inhibitor 3d maintains excellent potency against a variety of multi-PI-resistant clinical strains. Our structure-activity studies indicate that the ring size, stereochemistry, and position of oxygens are important for the observed activity. Optically active synthesis of 1,3-dioxepan-5-ol along with the syntheses of various cyclic ether and polyether ligands have been described. A protein-ligand X-ray crystal structure of 3d-bound HIV-1 protease was determined. The structure revealed that the P2-ligand makes extensive interactions including hydrogen bonding with the protease backbone in the S2-site. In addition, the P2-ligand in 3d forms a unique water-mediated interaction with the NH of Gly-48.
- Ghosh, Aran K.,Gemma, Sandra,Baldridge, Abigail,Wang, Yuan-Fang,Kovalevsky, Andrey Yu.,Koh, Yashiro,Weber, Irene T.,Mitsuya, Hiroaki
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experimental part
p. 6021 - 6033
(2009/10/23)
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- Probing molecular shape. 1. Conformational studies of 5- hydroxyhexahydropyrimidine and related compounds
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(Chemical Equation Presented) Understanding the factors that determine molecular shape enables scientists to begin to understand and tailor molecular properties and reactivity. Many biomolecules and bioactive compounds contain aliphatic heterocyclic rings whose conformations play a major role in their biological activity. The interplay of a number of factors, both steric and electronic, is examined for 5-hydroxyhexahydropyrimidine (1) and related compounds with use of spectroscopy and molecular modeling.
- Locke, Julie M.,Crumbie, Robyn L.,Griffith, Renate,Bailey, Trevor D.,Boyd, Susan,Roberts, John D.
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p. 4156 - 4162
(2008/02/05)
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- Investigations on heterogeneously catalysed condensations of glycerol to cyclic acetals
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The acid-catalysed condensation of glycerol, a chemical from renewable materials, with benzaldehyde, formaldehyde, acetone (acetalisation), and their dimethyl acetals (transacetalisation) to mixtures of [1,3]dioxan-5-ols and [1,3]dioxolan-4-yl-methanols was investigated. Various solid acids were evaluated as heterogeneous catalysts for the desired glycerol conversion into these potential novel platform chemicals. [1,3]dioxan-5-ols are of particular interest as precursors for 1,3-propanediol derivatives. Therefore, the reported investigations were focused on the identification of reaction conditions that promote the formation of [1,3]dioxan-5-ols and suppress the formation of [1,3]dioxolan-4-yl-methanols.
- Deutsch,Martin,Lieske
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p. 428 - 435
(2007/10/03)
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- 4-Substituted dioxolanes by chemoselective reactions on glycerol formal
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4-Hydroxymethyl-1,3-dioxolane contained in glycerol formal undergoes chemoselective transformations, which constitute a direct entry to 4-substituted-1,3-dioxolanes.
- Gras,Dulphy,Marot,Rollin
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p. 4335 - 4336
(2007/10/02)
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- 6- versus 5-ring selectivity during methylene acetals formation in glycerols
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A detailed analysis of the factors governing the synthesis of cyclic acetals of 12 methylated glycerol derivatives is made.The dioxane versus dioxolane ratio is discussed.Key Words: glycerol / methylenation / transacetalization / methylene acetal / dioxan / dioxolan
- Gras, J. L.,Poncet, A.
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p. 566 - 573
(2007/10/02)
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- TRANSACETALISATION DE TRIOLS A PARTIR DU DIMETHOXYMETHANE. SELECTIVITE ET APPLICATIONS SYNTHETIQUES
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THe LiBr assisted/acid catalyzed transacetalation of triols from DMM affords a highly selective method for the synthesis of hydroxy compounds bearing a dioxane ring.These compounds might further conveniently be alkylated by phase transfer catalyzis.
- Gras, Jean-Louis,Nouguier, Robert,Mchich, Mohammed
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p. 6601 - 6604
(2007/10/02)
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- Cyclohexanones: evidence of chair inversion and estimate for barriers to planarity from the far-infrared spectra
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The far-infrared spectra in the region of 50-450 cm-1 are reported for the vapours of cyclohexanone and the structurally related compounds tetrahydro-4H-pyran-4-one, tetrahydro-4H-thiopyran-4-one, tetrahydro-4H-pyran-3-one, 1,3-dioxan-5-one, and 4H-pyran-4-one.Except for the last mentioned, the spectra are characterized by two or in some cases three sequences of Q branches which are assigned to the out-of-plane deformations of the cyclohexanone ring.The lowest wavenumber sequence in each compound is believed to arise from a vibration which, if completely executed, would take the chair conformation to its equivalent via an inversion through the planar form.Each sequence is amenable to solution by a one-dimensional Hamiltonian incorporating a quadratic-quartic potential function, providing estimates for the magnitudes of the barriers to planarity.
- Smithson, Tracy L.,Ibrahim, Nan,Wieser, Hal
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p. 1924 - 1932
(2007/10/02)
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- 5-Benzyloxy-1,3-dioxanes
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Herbicidal compositions containing compounds of the formula STR1 where R2 is hydrogen, hydrocarbyl or substituted hydrocarbyl radical; R2a is hydrogen or methyl and R2 and R2a may together form a ring; R5 is hydrogen, alkyl, haloalkyl or cyanoalkyl; Rr is aryl, substituted aryl or heterocyclyl.
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