600-14-6Relevant academic research and scientific papers
MECHANISM OF OXIDATION OF SOME ALIPHATIC KETONES BY N-BROMOSUCCINIMIDE IN ACIDIC MEDIA
Singh, Bharat,Pandey, Lalji,Sharma, J.,Pandey, S. M.
, p. 169 - 172 (1982)
Kinetics of the oxidation of methyl n-propyl ketone and methyl isobutyl ketone by N-bromosuccinimide (NBS) have been studied in perchloric acid media in presence of mercuric acetate.A zero order dependence to N-bromosuccinimide and a first order dependence to both ketones and hydrogen ion concentrations have been observed.Sodium perchlorate, mercuric acetate and succinimide additions have negligible effect while methanol addition has a positive effect on the reaction rate.A solvent isotope effect (k0D2O/K0H2O=2.3-2.7 and 2.4-2.8 for MeCOn.pr and MeCOi-Bu, respectively) has been observed at 35 deg.Kinetic investigations have revealedthat the order of reactivity is methyl n-propyl ketone>methyl isobutyl ketone.Various thermodinamic parameters have been computed and corresponding 1,2-diketones were found to be the products.A suitable mechanism in conformity with the above observations has been proposed.
Highly efficient and robust Mg0.388Al2.408O4 catalyst for gas-phase decarbonylation of lactic acid to acetaldehyde
Tang, Congming,Zhai, Zhanjie,Li, Xinli,Sun, Liangwei,Bai, Wei
, p. 206 - 217 (2015)
Abstract The process for decarbonylation of lactic acid into acetaldehyde over magnesium aluminum oxides was explored. Magnesium aluminum oxides were prepared with co-precipitation method by varying pH values, Mg/Al molar ratios and calcination temperatures. The as-prepared magnesium aluminum oxides were characterized by nitrogen adsorption-desorption, XRD, FT-IR, NH3-TPD, CO2-TPD and SEM, and were employed to catalyze the gas-phase decarbonylation of lactic acid to produce acetaldehyde. It is found that pH value is a crucial factor for the formation of magnesium aluminum oxides. At pH = 7-8, the obtained magnesium aluminum oxide is indexed to Mg0.388Al2.408O4, while at pH > 8, it is ascribed to MgAl2O4 spinel. At low calcination temperature such as 550°C, Mg0.388Al2.408O4 can be formed, and it enhances crystallinity with an increase of calcination temperature. However, as the calcination temperature exceeded 1200°C, the structure of Mg0.388Al2.408O4 encountered a serious destruction. Comparative study on catalytic performance for Mg0.388Al2.408O4 and MgAl2O4 spinel suggests that the former has more excellent performance than the latter. Besides mixtures including Mg0.388Al2.408O4 and Al2O3, pure MgO and pure Al2O3 were also investigated on their catalytic performance. In the presence of Mg0.388Al2.408O4, the stability experiment was performed at high LA LHSV such as 13.0 h-1. Encouragingly, the decarbonylation reaction of lactic acid proceeded efficiently at around 500 h on stream, and acetaldehyde selectivity remained constant (ca. ～93%).
An efficient and durable hierarchically porous KLA/TiPO catalyst for vapor phase condensation of lactic acid to 2,3-pentanedione
Zhang, Ju,Li, Xinli,Pang, Jun,Zou, Weixin,Tang, Congming,Dong, Lin
, p. 5972 - 5979 (2019)
Sustainable production of 2,3-pentanedione from bio-lactic acid via a vapor condensation reaction over KLA/TiPO (KLA: potassium lactate) was investigated in this work. A KNO3 precursor supported on the surface of TiPO was in situ converted to basic sites in a KLA/TiPO catalyst. KLA together with Ti4+(Lewis acidic site) make up the acid-base pairs in the KLA/TiPO catalyst, resulting in excellent activity for the condensation of lactic acid to 2,3-pentanedione. The loading amount of KNO3 was shown to have an important influence on the catalytic performance, since the acid-base properties of the catalysts were found to vary with the addition of KNO3. Reaction conditions such as lactic acid feed flow rate and lactic acid concentration were also discussed. Both lactic acid conversion and 2,3-pentanedione selectivity increased with elevated lactic acid feed flow rates, indicating the existence of an external diffusion resistance of the lactic acid reactant during the catalytic reactions. However, the lactic acid feed flow rate increased to 1.0 mL h?1 (corresponding to LA liquid hourly space velocity (LHSV) = 2.6 H?1), and the external diffusion resistance was efficiently eliminated. Enhancing the LA concentration improved the selectivity of 2,3-pentanedione, suggesting that the reaction order of the lactic acid molecule for lactic acid conversion to 2,3-pentanedione is higher than the other side reactions. Encouragingly, in retaining 30-45% of the lactic acid conversion, the condensation reaction with a 2,3-pentanedione selectivity of around 73% proceeded efficiently for at least 116 h on stream. The long-term stability of the present catalyst was found to be related to its hierarchical pores, which ameliorated the mass transfer effect of the reactant and product, except for the appropriate acid-base properties for lactic acid condensation to 2,3-pentanedione.
Sustainable production of acrylic acid: Rb+- and Cs+-exchanged Beta zeolite catalysts for catalytic gas-phase dehydration of lactic acid
Yan, Bo,Mahmood, Azhar,Liang, Yu,Xu, Bo-Qing
, p. 65 - 73 (2016)
Rb+- and Cs+-exchanged Beta zeolites (RbxNa1-xβ and CsxNa1-xβ) of varying exchange degrees (x = 0-1.00) were employed to catalyze the gas-phase dehydration of lactic acid (LA) for sustainable production of acrylic acid (AA) in a flow fixed-bed reactor at 360°C, using an aqueous solution of LA (10 mol% or 35.7%) as the reaction feed at a weight hourly space velocity by LA of 2.1 h-1. An appropriate window of the ion exchange degrees for highly selective AA production (≥60 mol%) was determined for either series of the samples, i.e., x = 0.85-0.98 for the RbxNa1-xβ and x = 0.71-0.90 for the CsxNa1-xβ samples. The best performing catalysts Rb0.95Na0.05β, and Cs0.81-0.90Na0.19-0.10β offered the highest AA selectivity (ca. 70 mol%) and yield (ca. 60-65 mol%) for reaction periods of longer than 10 h. Measurements of the surface acidity and basicity of the catalyst samples by temperature-programmed desorption of NH3 and CO2 showed that the highly selective catalysts in such widows should have both weakly acidic and weakly basic surface sites with suitably balanced acidity and basicity. The acid-catalyzed decarbonylation/decarboxylation and base-catalyzed condensation of LA, which lead respectively to formation of acetaldehyde and 2,3-pentanedione, always occurred as the competing reactions over the investigated catalysts. Observations on the catalyst selectivity changes for these competing reactions clearly demonstrate that the suitably balanced acidity and basicity at the catalyst surface is the key to the high selectivity for the desired dehydration reaction.
Potassium-Ion-Exchanged Zeolites for Sustainable Production of Acrylic Acid by Gas-Phase Dehydration of Lactic Acid
Yan, Bo,Tao, Li-Zhi,Mahmood, Azhar,Liang, Yu,Xu, Bo-Qing
, p. 538 - 550 (2017)
Development of high-performance solid acid catalysts for chemicals and materials production from bioresourced feedstock has become an important research topic in heterogeneous catalysis for renewable energy and green chemistry. We provide herein a comprehensive study on the catalytic performance of various K+-exchanged zeolites (KxNa1-xZ-y, x = 0.90-0.98) with similar molar K/Al ratios for acrylic acid (AA) production by gas-phase dehydration of lactic acid (LA) and discuss the effects of zeolite type (Z = ZSM-22, ZSM-35, MCM-22, ZSM-11, ZSM-5, ZSM-5/ZSM-11, and β) and SiO2/Al2O3 ratio (y). ZSM-5 and β are found more efficient than the other zeolites for this LA-to-AA reaction. Variation of y in the zeolite (β and ZSM-5) is shown to significantly affect the catalytic performance: not only higher AA selectivity and yield but also better catalytic stability is achieved by lowering y. A K0.97Na0.03ZSM-5-27 is then identified as the best-performing catalyst, offering very high AA selectivity (80-81 mol%) and yield (74-78 mol%) at 360 °C under high LA space velocity (WHSVLA = 2.1 h-1). This catalyst also shows a remarkable long-term stability, being capable to maintain a high AA selectivity (>70 mol%) and yield (>55 mol%) for longer than 80 h. Furthermore, an in situ calcination of the used catalyst with flowing air at 450 °C is shown to be efficient for complete catalyst regeneration. Correlating the catalyst performance with its surface acid-base property measured by NH3- and CO2-TPD clearly uncovers that balance between the surface acidity and basicity would be a key, besides Z and y of the zeolite, to the catalyst performance.
Efficient Conversion of Bio-Lactic Acid to 2,3-Pentanedione on Cesium-Doped Hydroxyapatite Catalysts with Balanced Acid–Base Sites
Li, Xinli,Sun, Liangwei,Zou, Weixin,Cao, Ping,Chen, Zhi,Tang, Congming,Dong, Lin
, p. 4621 - 4627 (2017)
We report the design and synthesis of cesium-doped hydroxyapatite for direct and high-yield conversion of biobased lactic acid to 2,3-pentanedione (72.3 %). Cs species derived from CsNO3 at high temperature of calcination is introduced into the hydroxyapatite structure to regulate its acid–base properties. It is found that a balance of acid–base chemistry favors the condensation of lactic acid to 2,3-pentanedione. As a result, the undesired reactions such as lactic acid dehydration, decarbonylation, and coking are suppressed. Instead, a concerted catalysis between surface basic site and acidic site for lactic acid condensation to 2,3-pentanedione dominates on the cesium-doped hydroxyapatite catalyst, leading to a highly selective process for direct conversion of bio-lactic acid to 2,3-pentanedione.
Selective conversion of lactic acid into acrylic acid over hydroxyapatite catalysts
Matsuura, Yumiko,Onda, Ayumu,Yanagisawa, Kazumichi
, p. 5 - 10 (2014)
Lactic acid conversion into acrylic acid was carried out over Ca-HAP catalysts at 623 K. Stoichiometric Ca-HAP catalyst gave a high acrylic acid yield of about 60 C-%. Furthermore, non-stoichiometric calcium deficient Ca-HAP catalysts containing the specific amounts of sodium ions, which were prepared under hydrothermal conditions, exhibited remarkably high acrylic acid yields of about 80 C-%. In contrast, non-stoichiometric Ca-HAP catalysts with vacancy sites and Ca-HAP catalysts with excess amounts of sodium species showed relatively low acrylic acid yields and high selectivities into acetaldehyde and 2,3-pentanedione.
Synthesis method of pentanediol and synthesis method for preparing biomass-based linear pentadiene based on lactic acid conversion
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Paragraph 0204-0206; 0211-0213; 0218-0220; 0225-0227, (2021/05/19)
The invention provides a method for synthesizing pentanediol. The method comprises the following steps: carrying out hydrogenation reaction on a mixed solution obtained by mixing pentanedione, a hydrogenation catalyst and an organic solvent in a hydrogen-containing atmosphere to obtain the pentanediol. According to the invention, a large amount of cheap and easily available bio-based chemical lactic acid can be utilized to obtain pentanediol, and linear pentadiene is further obtained; the raw materials are from renewable resources, and linear pentadiene is obtained through the following steps: (1) condensing lactic acid to prepare pentanedione, (2) hydrogenating pentanedione to prepare pentanediol, and (3) dehydrating pentanediol to obtain linear pentadiene; linear pentadiene, especially 1, 3-pentadiene, is prepared from lactic acid through a process route of condensation, hydrogenation and dehydration; and a green and sustainable linear pentadiene synthesis method based on bio-based chemical conversion is provided, and is simple to operate, short in process, free of harsh experimental conditions, easy to prepare raw materials and catalysts, and has a large-scale synthesis prospect.
Confined alkali metal ions in two-dimensional aluminum phosphate promoted activity for the condensation of lactic acid to 2,3-pentanedione
Dai, Yunsheng,Li, Xinli,Tang, Congming,Yang, Chenglong,Zhang, Ju
supporting information, p. 13806 - 13813 (2021/08/16)
The sustainable production of 2,3-pentanedione from bio-lactic acid was investigated over alkali metal ion-intercalated laminar aluminum phosphate. The confined alkali metal ion through the adjacent layers of aluminum phosphate offered excellent stability for the condensation of lactic acid to 2,3-pentanedione at least 80 h on stream, remaining constant at 55% conversion of lactic acid as well as around 80% of 2,3-pentanedione selectivity. The intercalated alkali metal ions can efficiently stabilize the enol intermediate, promoting the activity of lactic acid condensation. Besides, it can also prevent the occurrence of a layered stack of aluminum phosphate, providing an excellent mass transfer space for molecular diffusion, which is demonstrated by the calculation of the relation between molecular mean free paths for lactic acid and 2,3-pentanedione and the interlamellar spacing of aluminum phosphate. As a result, the alkali metal ion-intercalated laminar aluminum phosphate exhibited excellent performance for the condensation of lactic acid to 2,3-pentanedione at 270 °C, achieving 90% of lactic acid conversion and 80% of selectivity towards 2,3-pentanedione.
PREPARATION METHOD OF ACRYLIC ACID FROM LACTIDE BY USING ION EXCHANGE RESIN
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Paragraph 0050; 0067-0071, (2019/10/11)
The present invention provides a method for manufacturing acrylic acid from a dehydration reaction of lactide derived from biomass using two or more strongly acidic cation exchange resins, for example, a strong acid cation exchange resin having a particle
