2155-30-8Relevant academic research and scientific papers
Promotion effect of Sn on Au/Sn-USY catalysts for one-pot conversion of glycerol to methyl lactate
Lu, Tianliang,Fu, Xiaomin,Zhou, Lipeng,Su, Yunlai,Yang, Xiaomei,Han, Li,Wang, Jianfeng,Song, Chengying
, p. 7274 - 7284 (2017)
Herein, hierarchical bifunctional catalysts of Sn-USY-supported Au nanoparticles were designed for the one-pot conversion of glycerol (GLY) to methyl lactate (MLA). Over Au/Sn-USY catalyst, 79% MLA yield can be obtained with a high selectivity (～90%). The promotion effect of Sn was investigated, and the interaction between extraframework SnOx and Au was confirmed by TEM, pyridine-FT-IR, CO-FT-IR, and XPS. The interaction promotes the dispersion of Au particles (smaller and much more uniform). This is important for the oxidation of GLY to 1,3-dihydroxyacetone (DHA) and glyceraldehyde (GA), which are the intermediate species for the conversion of GLY to MLA. Meanwhile, introduction of Sn modified the acid properties of the catalyst, which are critical for the selective conversion of DHA and GA to MLA.
Tandem catalytic conversion of glycerol using solid catalysts followed by transesterification to produce alkyl lactate
Ren, Shoujie,Ye, X. Philip,Ayers, Paul D.
, p. 53230 - 53239 (2015)
This study investigated alkyl lactate production from glycerol by tandem processes which included glycerol conversion to calcium lactate using solid catalysts and subsequent transesterification of calcium lactate to alkyl lactate using methanol/ethanol and carbon dioxide. The effect of reaction conditions on alkyl lactate production was systematically investigated. A central composite design (CCD) and response surface methodology were used to design the experiments and evaluate the optimum process conditions. At the optimum conditions, the methyl lactate yield reached 57 mol% with a glycerol conversion of 94 mol% using refined glycerol. A yield of approximately 42 mol% for ethyl lactate was obtained using refined glycerol at the optimum conditions. Similar glycerol conversion and alkyl lactate yields were obtained using crude glycerol, indicating that the impurities in the crude glycerol had no significant effects on alkyl lactate production. The examination of regenerated catalysts that had been reused twice showed no negative effects on glycerol conversion and methyl lactate production. Compared to the traditional lactic acid and alkyl lactate production, this two-step process for alkyl lactate production from glycerol is both economical and environmentally benign since no gypsum was produced and the solid catalysts can be regenerated and reused.
Tin-Carboxylate MOFs for Sugar Transformation into Methyl Lactate
Murillo, Beatriz,Zornoza, Beatriz,de la Iglesia, Oscar,Wang, Sujing,Serre, Christian,Téllez, Carlos,Coronas, Joaquín
, (2019)
With the purpose of improving the production of methyl lactate (ML) from sugars (glucose and sucrose), a new metal-organic framework (MOF) denoted as UZAR-S10, containing Sn ions and ligand 2-aminobenzene-1,4-dicarboxylate was synthesized. The SEM and PXRD characterization revealed that UZAR-S10 was highly crystalline. The empirical formula of UZAR-S10 is [(NH2-BDC)Sn]·(NH2-BDC)0.5, i.e., per Sn atom, with one structural ligand molecule and half ligand molecule trapped in the MOF structure. The removal of the trapped ligand by either solvent extraction or thermal treatment damaged the structure of UZAR-S10, not enabling its activation. The performance of UZAR-S10 in the production of ML was compared to those achieved with different types of carboxylate MOFs, especially with that of Sn partially substituted Ti tetracarboxylate MOF denoted MIP-177-LT (MIP-177-LT(Ti/Sn)). The highest ML yields achieved from sucrose were 29.5 % and 42.0 % for UZAR-S10 and MIP-177-LT(Ti/Sn), respectively. For comparison, other carboxylate type MOFs (MIL-53(Al), NH2-MIL-53(Al), UiO-66, MIL-101(Cr) and HKUST-1) were tested at the same conditions with worse performance than the two Tin-containing MOFs.
Dinuclear zinc-N-heterocyclic carbene complexes for either the controlled ring-opening polymerization of lactide or the controlled degradation of polylactide under mild conditions
Fliedel, Christophe,Vila-Vicosa, Diogo,Calhorda, Maria Jose,Dagorne, Samuel,Aviles, Teresa
, p. 1357 - 1367 (2014)
We describe the synthesis of the new Zn-N-heterocyclic carbene (NHC) alkoxide complexes [(S,CNHC)ZnCl(OBn)]2 (5) and [(O,C NHC)ZnCl(OBn)]2 (6) for use as ring-opening polymerization (ROP) initiators for lactide polymerization. Complexes 5 and 6 are readily available through an alcoholysis reaction between BnOH and the corresponding Zn-NHC ethyl species [(S,CNHC)ZnCl(Et)] (3) and [(O,C NHC)ZnCl(Et)] (4), and species 3 and 4 were obtained from the reaction of ZnEt2 with the N-methyl-N'-ethylphenylsulfide (1HCl) and N-methyl-N'-ethylmethylether (2HCl) imidazolium salts, respectively. Both solution and solid-state structural data for Zn benzyloxide species 5 and 6 agree with dimeric structures under the studied conditions (reaction conditions: CH2Cl2 or THF, room temperature). A computational analysis of species 3 and 4 supports a dimeric structure in solution. The ZnII alkoxide species 5 and 6 were found to mediate either the ROP of lactide (in an effective and controlled manner) to produce chain length-controlled polylactide (PLA) or, in the presence of an alcohol source such as MeOH, the controlled degradation of PLA through extensive transesterification reactions to afford methyl lactate as the major product. A thorough DFT computational analysis of the ROP of lactide initiated by complex 5 was performed, which revealed that the operating coordination-insertion mechanism was assisted by the second Zn center, leading to a lower-energy ROP process; this result may be of interest for the future design of well-defined and high-performance metal-based catalysts. Mild thing: Simple dinuclear zinc-N-heterocyclic carbene (NHC) alkyl/alkoxide complexes mediate, under mild conditions, either the ring-opening polymerization of lactide (in an effective and controlled manner) for the production of chain length-controlled polylactide or, in the presence of an alcohol source such as MeOH, the controlled depolymerization of polylactide through extensive transesterification reactions.
Chemocatalysis of sugars to produce lactic acid derivatives on zeolitic imidazolate frameworks
Murillo, Beatriz,Zornoza, Beatriz,De La Iglesia, Oscar,Téllez, Carlos,Coronas, Joaquín
, p. 60 - 67 (2016)
Several research studies related to biorefining have focused on developing routes for biomass conversion into biomaterials or platform molecules. In this work, the zeolitic imidazolate frameworks (ZIFs) ZIF-8 and ZIF-67 have been tested as catalysts in th
Highly selective and immortal magnesium calixarene complexes for the ring-opening polymerization of rac-lactide
Walton, Mark J.,Lancaster, Simon J.,Redshaw, Carl
, p. 1892 - 1898 (2014)
The lithiation of 1,3-dipropoxy-p-tert-butylcalix[4]arene (LH2) followed by reaction with nBuMgBr in THF resulted in the formation of the hetero-bimetallic complex [Li(THF)Mg(nBu)L] (1). By contrast, the treatment of tripropoxy-p-tert-butylcalix[4]arene (LH) with nBu2Mg afforded a mononuclear complex [LMg(nBu)] (2). Single-crystal XRD studies revealed that in both structures the calix[4]arene adopts a cone conformation, and a Li cation resides in the cavity for 1. Both 1 and 2 were active for the ring-opening polymerisation of rac-lactide. Compound 2 displayed not only exceptional activity (100 equivalents, 3 min, 92% conversion, BnOH, room temperature) but also high selectivity (probability to form an r dyad, Pr=0.85) and exhibited an immortal character in THF. Surprisingly, compound 2 also showed isotactic bias (Pr=0.30-0.36) and an immortal character if toluene was employed as the solvent; 2D J-resolved 1H NMR spectroscopy was employed for the assignment of the stereoselectivity.
Confinement of Ultrasmall Cobalt Oxide Clusters within Silicalite-1 Crystals for Efficient Conversion of Fructose into Methyl Lactate
Yan, Yue,Zhang, Zihao,Bak, Seong-Min,Yao, Siyu,Hu, Xiaobing,Shadike, Zulipiya,Do-Thanh, Chi-Linh,Zhang, Feng,Chen, Hao,Lyu, Xilei,Chen, Kequan,Zhu, Yimei,Lu, Xiuyang,Ouyang, Pingkai,Fu, Jie,Dai, Sheng
, p. 1923 - 1930 (2019)
Chemocatalysis of sugars to methyl lactate (MLA) exhibits great advantages over the conventional fermentation approach because of its higher productivity and cost-effective separation process. However, widely used supported metal oxide catalysts suffer from deactivation resulting from sintering during the reaction and removal of coke at high temperatures. Herein, we report ultrasmall cobalt oxide clusters (～1.7 nm) stabilized within silicalite-1 crystals catalyst (CoO@silicalite-1), exhibiting superior catalytic activity and resistance to sintering for the conversion of fructose into methyl lactate. HAADF-STEM, EDS-mapping, and XRD experiments identify the existence of confined CoO clusters. XANES and Raman spectra demonstrated the covalent interaction between CoO and silicalite-1. Thanks to the ultrasmall CoO particle size (～1.7 nm), the CoO@silicalite-1 affords nearly 100-fold higher Co-mass-based activity (mg MLA/mg Co) compared with CoO or Co3O4 particles outside the silicalite-1 framework. More importantly, this catalyst exhibits good reuse performance via the removal of coke with facile calcination.
Two-Step Continuous-Flow Synthesis of Fungicide Metalaxyl through Catalytic C?N Bond-Formation Processes
Ishitani, Haruro,Yu, Zhibo,Ichitsuka, Tomohiro,Koumura, Nagatoshi,Onozawa, Shun-ya,Sato, Kazuhiko,Kobayashi, Shū
, p. 18 - 23 (2022)
Metalaxyl, an acylalanine fungicide, was synthesized through catalytic continuous sequential-flow reactions. Commonly used syntheses of this compound use batch systems and suffer from problems such as coproduction of halogen-containing by-products derived from acyl and alkyl halides in the substitution reactions of 2,6-dimethylaniline. To minimize waste and enhance efficiency, a halide-free approach including two continuous-flow catalytic processes, heterogeneous Pt-catalyzed reductive alkylation and homogeneous acid-catalyzed amidation with an acid anhydride, was developed. Systematic examination of the two reactions in flow mode enabled a high-yielding, two-step sequential continuous-flow process to be achieved. (Figure presented.).
Conversion of lactides into ethyl lactates and value-added products
Bykowski, Dominik,Grala, Agnieszka,Sobota, Piotr
, p. 5286 - 5289 (2014)
This Letter describes an attractive and efficient method for Mg(OR)2-mediated lactide alcoholysis. The catalysts were generated in situ from di-n-butylmagnesium and ROH to prevent aggregation of Mg(OR)2. The reaction of ROH [R = Me,
Asymmetric nitrogen: 81. * diastereomeric derivatives of 1-alkoxy-2,2-bis(trifluoromethyl)aziridines. Structure and absolute configuration
Prosyanik,Mishchenko,Zelenskaya,Forni,Moretti,Torre,Bruekner,Malpezzi,Kostyanovsky,Kostyanovsky
, p. 1359 - 1364 (1998)
The 1H NMR spectra of O-derivatives of 1-hydroxy-2,2-bis(trifluoromethyl)aziridine containing such substituents as EtO2CCH2, (R/S)-RO2CCH(Me) (R = Me, Pri, or But), (R/S)-H2NC(O)CH(Me), and (R)-H2NC(O)CH(Me) were analyzed. Both of the diastereomerically pure amides of the latter type were isolated. The validity of the 1H NMR criteria, which were suggested for the determination of absolute configurations of diastereomers of N-alkoxyaziridines, was confirmed by X-ray diffraction study of the (R,R)-amide.
