597-31-9Relevant academic research and scientific papers
A CaMnAl-hydrotalcite solid basic catalyst toward the aldol condensation reaction with a comparable level to liquid alkali catalysts
Zheng, Lirong,Bing, Weihan,Wang, Huimin,Zheng, Lei,Rao, Deming,Yang, Yusen,Wang, Bin,Wang, Yangdong,Wei, Min
, p. 3071 - 3080 (2018)
In a number of heterogeneous catalysis processes, the promotion effect toward active sites is of vital importance and remains a challenge to obtain largely-improved catalytic performance. Herein, rehydrated Ca4MnxAl-layered double hydroxides (denoted as re-Ca4MnxAl-LDH) were prepared based on a structure memory effect of LDH precursors, which exhibited extremely high heterogeneous catalytic performance for the aldol condensation reaction, with the assistance of the promotion effect of Mn. A combination study including XRD, EXAFS, XPS, CDCl3-FTIR and DFT calculations confirms that re-Ca4MnxAl-LDH samples with Ca-O-MnIV structure show a highly-exposed Ca2+ s-orbital and strengthened coordination between Ca2+ with 7-fold OH-, providing a weakened Br?nsted basic site compared with the reference sample re-Ca4Al-LDH. The optimized re-Ca4Mn0.5Al-LDH catalyst exhibits prominent catalytic performance toward the condensation of isobutyraldehyde (IBD) and formaldehyde (FA) to produce hydroxypivaldehyde (HPA), with a HPA yield of 70.3%. This is significantly higher than re-Ca4Al-LDHs (63.3%) and even comparable to the level of liquid alkali catalysts (73.2%). Studies on the structure-property correlation reveal that the weakened basic site originating from Ca-O-MnIV serves as a promoted active center, which accelerates the product desorption and thus largely improves HPA selectivity. This promoted re-Ca4Mn0.5Al-LDH catalyst can be potentially applied as a promising candidate in heterogeneous aldol condensation reactions.
Asymmetric synthesis of (R)-3,3-dimethyl-2-hydroxy-γ-butyrolactone en route to the formal synthesis of calcium D-pantothenate
Rama Rao,Mahender Rao,Sharma
, p. 5735 - 5738 (1994)
An efficient asymmetric protocol for the synthesis of (R)-3,3-dimethyl-2- hydroxy-γ-butyrolactone, a crucial intermediate for the synthesis of calcium D-pantothenate and several other compounds is described, where the requisite chirality is incorporated by Sharpless asymmetric epoxidation reaction.
Poly(ethylene glycol) with Multiple Aldehyde Functionalities Opens up a Rich and Versatile Post-Polymerization Chemistry
Blankenburg, Jan,Maciol, Kamil,Hahn, Christoph,Frey, Holger
, p. 1785 - 1793 (2019)
Two novel epoxide monomers 3,3-dimethoxy-propanyl glycidyl ether (DMPGE) and 3,3-dimethoxy-2,2-dimethylpropanyl glycidyl ether (DDPGE) were developed for the introduction of multiple aldehyde functionalities into the poly(ethylene glycol) (PEG) backbone. The acetal protecting group for the aldehyde functionality is stable against the harsh, basic conditions of the anionic ring-opening polymerization. Both monomers could be homopolymerized as well as copolymerized randomly with ethylene oxide (EO) in a controlled fashion. Copolymers with molecular weights (Mn) in the range of 4500-20100 g/mol and low dispersity (Mw/Mn) between 1.06 and 1.14 were obtained. The polymers were characterized by size exclusion chromatography, 1H NMR spectroscopy, and by differential scanning calorimetry regarding their thermal properties. The controlled character of the copolymerization was verified by MALDI-TOF. To study the distribution of the acetal-protected aldehyde functionalities at the polyether chains, the copolymerization with EO was monitored by in situ 1H NMR kinetics experiments for both monomers. These measurements revealed almost ideally random distribution of the comonomers with reactivity ratio pairs rEO = 0.96, rDMPGE = 1.04 and rEO = 1.20, rDDPGE = 0.83. The acetal functionalities of DMPGE polymers were successfully addressed by hydrazone formation. In addition, DDPGE copolymers were successfully deprotected in acidic media, and various transformations yielded aldehyde-, ester-, and nitrile-functionalized PEG while maintaining a dispersity below 1.1. Consequently, these monomers represent promising building blocks for the synthesis of multifunctional PEG for a variety of biomedical purposes.
Calcium pantothenate. Part 2. Optimisation of oxynitrilase-catalysed asymmetric hydrocyanation of 3-hydroxy-2,2-dimethylaldehyde: Synthesis of (R)-pantolactone
Synoradzki, Ludwik,Rowicki, Tomasz,Wlostowski, Marek
, p. 103 - 108 (2006)
The synthesis of (R)-pantolactone via oxynitrilase-catalysed asymmetric hydrocyanation of 3-hydroxy-2,2-dimethylaldehyde has been investigated. (R)-Oxynitrilases from almonds as well as from apple and plum kernels were employed as catalysts in the form of defatted meal. A number of factors influencing the hydrocyanation process have been studied and the conditions optimised using statistical methods. (R)-Pantolactone with 74% yield and 30% ee has been synthesised.
Preparation method of DL-pantoic acid lactone
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Paragraph 0042-0045; 0048-0051; 0054-0057, (2021/02/06)
The invention discloses a preparation method of DL-pantoic acid lactone, which comprises the following steps: reacting formaldehyde with isobutyraldehyde in the presence of a basic catalyst, slowly dropwise adding the reaction solution into sodium cyanide, adding an acid solution after the reaction is finished, and carrying out esterification reaction to obtain the DLpantoic acid lactone. The reaction is carried out in a water system, high-temperature and high-pressure reaction conditions are not needed, the process safety performance is high, the energy-saving and consumption-reducing effectsare obvious, and a high-content target product is obtained at a high yield, so that the production cost is reduced, and the method is a safe and simple DL-pantoic acid lactone production method.
Preparation method of hydroxypivalaldehyde and application of hydroxypivalaldehyde in preparation of neopentyl glycol
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Paragraph 0039-0041; 0044-0046; 0049-0051, (2021/02/09)
The invention provides a preparation method of 2,2-dimethyl-3-hydroxypropanal and application thereof in preparation of neopentyl glycol. The 2,2-dimethyl-3-hydroxypropanal is prepared from an epoxy compound by a hydroformylation method. The method has the advantages of good atom economy, low raw material cost, no wastewater generation, and high yield. The invention also provides the application of the 2,2-dimethyl-3-hydroxypropanal in preparation of the neopentyl glycol. The application method circumvents the disadvantages of the conventional methods in the prior art, the reaction system is simple, and the industrial application prospect is excellent.
Method for improving selectivity of aldol condensation reaction
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Paragraph 0028-0030; 0037-0040, (2020/09/16)
The invention provides a method for improving selectivity of aldol condensation reaction. The method comprises the following steps: introducing C1-C5 aldehyde participating in the reaction and an aqueous solution of an alkaline compound into a coiled tube type reactor in a parallel flow manner, forming a continuous phase under a turbulence condition by the aqueous solution of the alkaline compound, and dispersing the C1-C5 aldehyde in the continuous phase in a droplet form. The C1-C5 aldehyde is selected from one or two of formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde and isovaleraldehyde; the alkaline compound is selected from at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate,ammonia water, trimethylamine, triethylamine and diisopropylamine. The invention also provides preparation of 1, 3-butanediol by condensation of acetaldehyde and an inorganic alkali compound and preparation of hydroxypivalaldehyde by condensation of formaldehyde, isobutyraldehyde and a trimethylamine aqueous solution. With application of the coiled tube type reactor, the reaction temperature, thematerial ratio and the retention time can be accurately controlled, side reactions are effectively reduced, and the reaction efficiency, the reaction stability and the product selectivity are improvedby adopting the reaction process.
Preparation method of hydroxyaldehyde and method for resolving optical isomer by using electrodialysis technology
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Paragraph 0232-0250, (2020/12/15)
The present invention provides a process for preparing hydroxyaldehydes using an immobilized catalyst, wherein the immobilized catalyst comprises a solid support and a tertiary amine-based functionalgroup. The invention also provides a method for preparing a polyhydroxy alcohol compound and a polyhydroxy acid compound. The invention further provides a method for splitting the optical isomer fromthe raceme through electrodialysis.
Enhancing the photo-efficacy of an organic visible-light-activated chromophore (alizarin red S) on zinc oxide with a Ag-Na electrolyte to photo-transform aromatic and aliphatic alcohols
Underwood, Timothy M.,Robinson, Ross S.
, p. 24259 - 24266 (2019/08/15)
The development of an aqueous silver-sodium/alizarin red sensitised zinc oxide system has been reported to oxidise a range of both aromatic and aliphatic alcohols to aldehydes. Furthermore, photoluminescence spectroscopy validated the electron quenching effect of zinc oxide's defect sites after surface sensitising the metal-oxide with alizarin red. Powder diffuse reflectance UV/Vis data further substantiated the visible-light attenuated properties of alizarin red sensitised zinc oxide, and hence justification for its visible light reactivity towards alcohol oxidations. Lastly, density functional theory calculations supported the intermolecular photo-electronic transfer between alizarin red organic and zinc oxide.
METHOD FOR PRODUCING HYDROXYPIVALALDEHYDE
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Paragraph 0155; 0188, (2019/02/05)
There is provided a method for producing hydroxypivalaldehyde (HPA), including steps (i) to (iii) below in this order, Step (i): a reaction step of reacting IBAL with FA to produce a reaction solution containing HPA, step (ii): an extraction step of extracting the reaction solution with an aldehyde solvent represented by formula (1) under basicity to obtain an extract containing HPA, and step (iii): a distillation and collection step of distilling the extract and then collecting HPA from the residue, wherein R represents a saturated alkyl group having 3 or more and 7 or less carbon atoms, further wherein the distillation step of the step (iii) is a step of distilling an extract in the presence of water, and an amount of the water which is subjected to the distillation is 100 parts by mass or more and 2,000 parts by mass or less, with respect to a total amount, 100 parts by mass, of isobutyraldehyde (IBAL) derived from a raw material and an aldehyde solvent represented by formula (1) in an extract which is subjected to the distillation. The method enables HPA to be mass-produced and the collecting ratio of HPA to be improved while selectively removing impurities other than water contained in HPA, specifically IBAL and the like. According to the method for producing HPA as mentioned above, it is possible to reduce the content of neopentyl glycol-isobutyrate, isobutylaldehyde-hydroxypivalaldehyde-acetal, and isobutylaldehyde-hydroxypivalaldehyde-aldol as specific impurities byproduced from HPA.
