4547-43-7Relevant articles and documents
Towards efficient Cu/ZnO catalysts for ester hydrogenolysis: The role of synthesis method
Aubrecht, Jaroslav,Kikhtyanin, Oleg,Kubi?ka, David,Pospelova, Violetta
, (2021)
Cu/ZnO catalysts represent an environmentally friendly alternative to Adkins catalysts used for ester hydrogenolysis. Cu/ZnO are mostly synthesized by co-precipitation (COP); however, other synthesis methods may help to obtain small highly dispersed Cu crystallites advantageous for catalyst activity. A comparative study on the effect of synthesis method on Cu/ZnO catalysts properties and activity is missing. Thus, we synthesized 8 wt% Cu/ZnO catalysts by five methods (COP, deposition-precipitation (DP), chemisorption-hydrolysis (CH), incipient wetness (IWI) and wet impregnation (WI)), characterized and tested them in dimethyl adipate hydrogenolysis. The CH-prepared catalyst was prone to Cu sintering, which impaired its performance. IWI led to large Cu nanoparticles, pore blocking and poor catalytic performance. COP and DP resulted in the smallest Cu nanoparticles (13?14 nm), largest Cu surface area (3.9–4.2 m2 gcat?1) and specific surface area (40?43 m2 gcat?1) reflected in their superior catalytic activity making DP a good alternative to COP to prepare active Cu/ZnO catalysts.
CATALYTIC OXIDATIVE COUPLING OF DIOLS BY Ru3(CO)12
Shvo, Youval,Blum, Yigal,Reshef, Deborah,Menzin, Marit
, p. C21 - C24 (1982)
Ru3(CO)12 acts as a homogeneous catalyst precursor for the transformation of α,ω-diols to polyesters and lactones.
Directing Selectivity to Aldehydes, Alcohols, or Esters with Diphobane Ligands in Pd-Catalyzed Alkene Carbonylations
Aitipamula, Srinivasulu,Britovsek, George J. P.,Nobbs, James D.,Tay, Dillon W. P.,Van Meurs, Martin
, p. 1914 - 1925 (2021/06/28)
Phenylene-bridged diphobane ligands with different substituents (CF3, H, OMe, (OMe)2, tBu) have been synthesized and applied as ligands in palladium-catalyzed carbonylation reactions of various alkenes. The performance of these ligands in terms of selectivity in hydroformylation versus alkoxycarbonylation has been studied using 1-hexene, 1-octene, and methyl pentenoates as substrates, and the results have been compared with the ethylene-bridged diphobane ligand (BCOPE). Hydroformylation of 1-octene in the protic solvent 2-ethyl hexanol results in a competition between hydroformylation and alkoxycarbonylation, whereby the phenylene-bridged ligands, in particular, the trifluoromethylphenylene-bridged diphobane L1 with an electron-withdrawing substituent, lead to ester products via alkoxycarbonylation, whereas BCOPE gives predominantly alcohol products (n-nonanol and isomers) via reductive hydroformylation. The preference of BCOPE for reductive hydroformylation is also seen in the hydroformylation of 1-hexene in diglyme as the solvent, producing heptanol as the major product, whereas phenylene-bridged ligands show much lower activities in this case. The phenylene-bridged ligands show excellent performance in the methoxycarbonylation of 1-octene to methyl nonanoate, significantly better than BCOPE, the opposite trend seen in hydroformylation activity with these ligands. Studies on the hydroformylation of functionalized alkenes such as 4-methyl pentenoate with phenylene-bridged ligands versus BCOPE showed that also in this case, BCOPE directs product selectivity toward alcohols, while phenylene-bridge diphobane L2 favors aldehyde formation. In addition to ligand effects, product selectivities are also determined by the nature and the amount of the acid cocatalyst used, which can affect substrate and aldehyde hydrogenation as well as double bond isomerization.
Method for preparing epsilon-caprolactone, 6-hydroxyhexanoic acid and esters thereof from tetrahydrofuranacetic acid and esters thereof
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Paragraph 0005; 0016; 0021; 0023; 0026-0027, (2021/05/29)
The invention provides a method for preparing epsilon-caprolactone and 6-hydroxyhexanoic acid and esters thereof from tetrahydrofuranacetic acid and esters thereof, which comprises the following steps: in a solvent, in a reducing atmosphere and under the action of a catalyst, carrying out reduction reaction on tetrahydrofuranacetic acid and ester compounds thereof under the conditions that the pressure is 0.1-10MPa and the temperature is 20-200 DEG C for 0.5-48 hours, separating the catalyst, and distilling out the solvent, so that the target products epsilon-caprolactone, 6-hydroxyhexanoic acid and ester compounds of 6-hydroxyhexanoic acid are obtained. According to the method, efficient conversion of bio-based tetrahydrofuranacetic acid and esters thereof is realized under relatively mild conditions, the produced epsilon-caprolactone and 6-hydroxycaproic acid and ester compounds thereof are polymer monomers and are wide in application, and the application range of biomass is expanded; and meanwhile, the dilemma that the preparation of [epsilon]-caprolactone, 6-hydroxycaproic acid and ester thereof must depend on fossil resources is solved.
Efficient Catalysts for the Green Synthesis of Adipic Acid from Biomass
Deng, Weiping,Yan, Longfei,Wang, Binju,Zhang, Qihui,Song, Haiyan,Wang, Shanshan,Zhang, Qinghong,Wang, Ye
supporting information, p. 4712 - 4719 (2021/01/20)
Green synthesis of adipic acid from renewable biomass is a very attractive goal of sustainable chemistry. Herein, we report efficient catalysts for a two-step transformation of cellulose-derived glucose into adipic acid via glucaric acid. Carbon nanotube-supported platinum nanoparticles are found to work efficiently for the oxidation of glucose to glucaric acid. An activated carbon-supported bifunctional catalyst composed of rhenium oxide and palladium is discovered to be powerful for the removal of four hydroxyl groups in glucaric acid, affording adipic acid with a 99 % yield. Rhenium oxide functions for the deoxygenation but is less efficient for four hydroxyl group removal. The co-presence of palladium not only catalyzes the hydrogenation of olefin intermediates but also synergistically facilitates the deoxygenation. This work presents a green route for adipic acid synthesis and offers a bifunctional-catalysis strategy for efficient deoxygenation.
Method for producing 1,6-hexanediol from 1,6-adipic acid by continuous esterification and hydrogenation
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Paragraph 0026; 0027, (2017/07/20)
The invention provides a method for producing 1,6-hexanediol from 1,6-adipic acid by continuous esterification and hydrogenation, belonging to the field of fine chemical synthesis. The method comprises the following steps: carrying out continuous esterification reaction on 1,6-adipic acid and methanol/ethanol in an acid-catalyst-filled reactive distillation tower, carrying out reduced pressure distillation purification on the dimethyl/ethyl adipate, and carrying out hydrogenation to obtain the methanol/ethanol and 1,6-adipic acid, wherein the methanol/ethanol returns to continue esterification, and the 1,6-adipic acid is used as the product. The esterification reaction product yield is 96% or above, and the hydrogenation reaction yield is greater than 99%. The method is simple to operate, implements the continuous esterification-purification-hydrogenation-separation production process, and has favorable economic benefits and industrial application prospects.
Introducing an in situ capping strategy in systems biocatalysis to access 6-aminohexanoic acid
Sattler, Johann H.,Fuchs, Michael,Mutti, Francesco G.,Grischek, Barbara,Engel, Philip,Pfeffer, Jan,Woodley, John M.,Kroutil, Wolfgang
supporting information, p. 14153 - 14157 (2015/02/19)
The combination of two cofactor self-sufficient biocatalytic cascade modules allowed the successful transformation of cyclohexanol into the nylon-6 monomer 6-aminohexanoic acid at the expense of only oxygen and ammonia. A hitherto unprecedented carboxylic acid capping strategy was introduced to minimize the formation of the deadend intermediate 6-hydroxyhexanoic acid. For this purpose, the precursor ε-caprolactone was converted in aqueous medium in the presence of methanol into the corresponding methyl ester instead of the acid. Hence, it was shown for the first time that esterases-specifically horse liver esterase-can perform the selective ring-opening of ε-caprolactone with a clear preference for methanol over water as the nucleophile.
METHOD FOR PRODUCING 1,6-HEXANEDIOL
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Page/Page column 6-7, (2012/02/04)
The invention relates to a process for preparing 1,6-hexanediol, preferably with at least 99.5% purity, which are especially virtually free of 1,4-cyclohexanediols, from a carboxylic acid mixture which is obtained as a by-product of the catalytic oxidation of cyclohexane to cyclohexanone/cyclohexanol with oxygen or oxygen-comprising gases and by water extraction of the reaction mixture, by hydrogenating the carboxylic acid mixture, esterifying and hydrogenating a substream to hexanediol.
HIGH-PURITY 1,6-HEXANEDIOL AND MANUFACTURING METHOD THEREOF
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Page/Page column 9-10, (2011/08/08)
There is provided a process for preparing 1,6-hexanediol by esterifying a carboxylic acid mixture resulted from oxidation of cyclohexane with oxygen, and then hydrogenating the esters, which substantially does not contain a compound leading to a high ester value. A process for preparing 1,6-hexanediol from a carboxylic acid mixture containing adipic acid and 6-hydroxycaproic acid, the carboxylic acid mixture is obtained as a by-product in oxidization of cyclohexane to cyclohexanone/cyclohexanol using oxygen or an oxygen-containing gas, the process comprises esterifying the acids with an alcohol, followed by hydrogenation, and the process is characterized by comprising the following steps of: a) separating a component having a boiling point lower than that of water and the alcohol used in the esterification from a mixture obtained by the hydrogenation in a first distillation step; b) separating an EV component having a boiling point higher than that of 1,6-hexanediol further in a second distillation step; c) separating an EV component having a boiling point lower than that of 1,6-hexanediol further in a third distillation step; and then d) obtaining 1,6-hexanediol in a fourth distillation step, in this order.
Kinetic analysis of terminal and unactivated C-H bond oxyfunctionalization in fatty acid methyl esters by monooxygenase-based whole-cell biocatalysis
Schrewe, Manfred,Magnusson, Anders O.,Willrodt, Christian,Buehler, Bruno,Schmid, Andreas
experimental part, p. 3485 - 3495 (2012/03/26)
The alkane monooxygenase AlkBGT from Pseudomonas putida GPo1 constitutes a versatile enzyme system for the ω-oxyfunctionalization of medium chain-length alkanes. In this study, recombinant Escherichia coli W3110 expressing alkBGT was investigated as whole-cell catalyst for the regioselective biooxidation of fatty acid methyl esters to terminal alcohols. The ω-functionalized products are of general economic interest, serving as building blocks for polymer synthesis. The whole-cell catalysts proved to functionalize fatty acid methyl esters with a medium length alkyl chain specifically at the ω-position. The highest specific hydroxylation activity of 104 U gCDW-1 was obtained with nonanoic acid methyl ester as substrate using resting cells of E. coli W3110 (pBT10). In an optimized set-up, maximal 9-hydroxynonanoic acid methyl ester yields of 95% were achieved. For this specific substrate, apparent whole-cell kinetic parameters were determined with a Vmax of 204±9 U gCDW -1, a substrate uptake constant (KS) of 142±17 μM, and a specificity constant Vmax/KS of 1.4 U g CDW-1 μM-1 for the formation of the terminal alcohol. The same E. coli strain carrying additional alk genes showed a different substrate selectivity. A comparison of biocatalysis with whole cells and enriched enzyme preparations showed that both substrate availability and enzyme specificity control the efficiency of the whole-cell bioconversion of the longer and more hydrophobic substrate dodecanoic acid methyl ester. The efficient coupling of redox cofactor oxidation and product formation, as determined in vitro, combined with the high in vivo activities make E. coli W3110 (pBT10) a promising biocatalyst for the preparative synthesis of terminally functionalized fatty acid methyl esters. Copyright
