Ketonization of fatty methyl esters over Sn−Ce−Rh−O catalyst

A mixture of methyl esters of fatty acids obtained by transterification of nonerucic rape oil was ketonized. The starting material, diluted with methanol, was converted at atmospheric pressure over a catalyst that contained Sn, Ce, and Rh oxides in a molar ratio of 90:9:1. At a temperature of 385°C ketones were obtained with a total yield of 63% at the 96% conversion of starting material. The reported experiments prove that catalysts other than iron that are active in ketonization of primary alcohols can be successfully used in ketonization of esters of fatty acids. The kind of diluent used plays a crucial role in the conversion.     

Aqueous‐phase ketonization of acetic acid over Zr/Mn mixed oxides

Aqueous‐phase ketonization possesses significant advantages over gas‐ or organic‐phase ketonization for improved conversion efficiency of aqueous fraction accompanied by algal bio‐oil production. In this study, synthetized ZrO₂ and Zr/Mn oxides are used for aqueous‐phase ketonization of acetic acid. ZrMn_0.5O_x shows the highest ketonization activity at 340°C for 12 h, achieving maximum acetone yield of 88.27%; and all catalysts exhibited selectivity higher than 96.75%. Apparent activation energy and acid reaction order are 161.2 kJ mol^?1 and 0.70, respectively. Results suggest high ketonization activity of poorly crystallized tetragonal ZrO₂. Addition of Mn results in ZrO₂/MnO_x solid solution and improves active sites. Acid property and Mn⁴⁺ content are important factors, and oxygen vacancy demonstrates relationship with ketonization activity for ZrO₂. Examination of recovered catalysts indicates that ZrMn_yO_x exhibits improved stability, and Mn leaching and crystal phase transformation are main causes of deactivation in aqueous‐phase ketonization. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2958–2967, 2017     

Reactions of normal alcohols in the presence of a dehydrogenating iron catalyst

A oxidizing condensation of normal alcohols C₄ to C₁₂ in the gas phase over Fe₃O₄ catalyst containing Cr, Si and K oxides was studied. The reactions were carried out in a continuous process at atmospheric pressure. Initially the alcohols undergo dehydrogenation to aldehydes and esters, and at higher temperatures symmetric ketones containing 2n - 1 atoms of carbon in a molecule are formed. A mechanism for the reaction is proposed. This revised version was published online in July 2006 with corrections to the Cover Date.     

New β-diketone-containing styrenic monomers and their polymers: Synthesis, keto-enol tautomerism and related fluorescence behavior

Three new β-diketone-containing styrenic monomers and their polymers were synthesized. The phenol and naphthol groups, and the electron-donating N,N-dimethylaniline groups were covalently attached to the β-diketone monomers at a designed position. The keto-enol tautomerism was characterized by ¹H, ¹³C NMR and UV-vis absorption spectroscopy. It was found that the β-diketone monomers exist in three forms, i.e. two cis-enol forms and one keto form. Their relative contents were determined by NMR spectroscopy. The β-diketone monomers bearing the phenol (1) and naphthol (2) groups display photoinduced enolization during UV irradiation due to the formation of intramolecular hydrogen bonds between the phenolic or naphtholic hydroxyl groups and the carbonyl groups. For their polymers and copolymers, however, photoinduced ketonization occurred during UV irradiation. The β-diketone monomer bearing N,N-dimethylaniline group (3) is a novel charge transfer fluorophore, which can be potentially employed as a dual-purpose functional monomer.     

Formation of long chain ketones over an iron catalyst

Primary aliphatic alcohols, aldehydes, esters, carboxylic acids, and their anhydrides undergo a transformation to ketones with high yield and selectivity. The reactions proceed in a continuous way in the gas phase over an iron catalyst. This revised version was published online in August 2006 with corrections to the Cover Date.     

乙酸与异丁酸催化合成甲基异丙基酮催化剂

采用浸渍法制备了一系列负载型催化剂,用于催化乙酸（AA）与异丁酸（IBA）酮化反应合成甲基异丙基酮（MIPK）。通过催化剂性能评价,筛选出较好的催化剂CeO2-TiO2/SiO2。用SEM、XRD、BET等方法对CeO2-TiO2/SiO2进行了表征。分别考察了不同反应温度与时间、原料组成、及进料空速等因素对反应活性和选择性的影响。结果表明：CeO2-TiO2/SiO2催化剂可有效催化AA与IBA催化合成MIPK,并且在450℃获得MIPK最高收率,450℃以后催化活性呈下降趋势。控制原料液相进料空速LHSV为0.5h-1,IBA与AA进料物质的量比为1∶1.7,水占原料的质量分数为10%,该催化剂于450℃连续反应30d后,异丁酸转化率由第1d的96.4%下降为82.6%,MIPK的收率由第1d的79.2%下降为70.5%。     

Ketonization of long chain esters from transesterification of technical waste fats

The methyl ester mixture obtained from rape oil, and the mixture of butyl esters produced from animal fatty acids, were converted into mixtures of ketones with a total yield above 65%. The experiments were performed at atmospheric pressure in a temperature range of 300–400 °C using a standard flow system, with an iron catalyst modified with silicon, chromium, and potassium oxides, in the molar ratio of 100 : 2 : 1 : 0.1. The described method may extend the prospects of using waste technical fats. © 2001 Society of Chemical Industry