Influence of the functionalization degree of acidic ion-exchange resins on ethyl octyl ether formation
摘要:
Ethyl octyl ether (EOE) can be obtained by the ethylation of 1-octanol by means of ethanol or diethyl carbonate over acidic ion-exchange resins. However, EOE formation has to compete with the less steric demanding formation of diethyl ether, by-product obtained from ethanol dehydration or diethyl carbonate decomposition. In the present work, the influence of the resin functionalization degree on EOE formation has been evaluated. A series of partially sulfonated resins (0.87-4.31 mmol H+/g) were prepared by the sulfonation of a macroreticular styrene-divinylbenzene copolymer. The catalysts were characterized, and subsequently, tested in a batch reactor (T = 150 degrees C, P = 25 bar). Amberlyst 15 and 46 were also tested for comparison purposes. Catalytic runs revealed that EOE formation occurred mainly in the firstly sulfonated domain of the polymer skeleton, the least crosslinked; while diethyl ether was formed in the whole polymer bead. Accordingly, the functionalization of the least accessible polymer domain, as a result of increasing the sulfonation temperature or by using a pre-swelling solvent, is not suitable to produce long chain ethers such as EOE; which are preferred as diesel fuels. (C) 2014 Elsevier Ltd. All rights reserved.
1-Methylcarbapenem compounds having antibacterial activity, pharmacologically acceptable esters or salts thereof and pharmaceutical compositions (particularly antibacterial agents) containing them as an active ingredient are described. In addition, the invention includes the use of these compounds, ester derivatives or salts for the manufacture of pharmaceutical compositions, or a method for the prevention or treatment of diseases (particularly bacterial infections) by administering a pharmacologically effective amount of the compounds, ester derivatives or salts to warm-blooded animals (particularly human beings).
Certain embodiments include carbonate esters of rapamycin at position 42 that are synthesized by a lipase catalyzed regio-specific process. These compounds or a pharmaceutically acceptable salt thereof are useful in the treatment of organ and tissue transplant rejection, autoimmune disease, proliferative disorder, restenosis, cancer, or microbial infection.
One-pot carbonyl reduction and carbonate formation using sodium borohydride in dialkyl carbonate solvents
作者:Abdulakeem Osumah、Jakob Magolan、Kristopher V. Waynant
DOI:10.1016/j.tetlet.2019.151203
日期:2019.10
Preparation of mixed carbonates proceeded in one step from ketones and aldehydes via treatment with NaBH4 in dimethyl or diethyl carbonate solvent at elevated temperatures. This is an efficient and convenient alternative to the traditional two-step sequence of carbonyl reduction to alcohol and subsequent carbonateformation by treatment with an alkyl chloroformate. 25 examples are presented from 49-92% yield
Immobilization of 1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene on Magnetic γ‐Fe
<sub>2</sub>
O
<sub>3</sub>
Nanoparticles: A Highly Recyclable and Efficient Nanocatalyst for the Synthesis of Organic Carbonates
作者:Liqiang Wu、Shuanbao Tian
DOI:10.1002/ejic.201301586
日期:2014.4
1,5,7-Triazabicyclo[4.4.0]dec-5-ene was immobilized on magnetic γ-Fe2O3 nanoparticles as a magneticnanocatalyst. The nanoparticle reagent was obtained with good loading levels and has been successfully used for the efficient and selective synthesis of organic carbonates by the direct condensation of alcohols and diethyl carbonate. The catalyst is quantitatively recovered by an external magnet and
Catalytic Activity of MCM-41–TBD in the Selective Preparation of Carbamates and Unsymmetrical Alkyl Carbonates from Diethyl Carbonate
作者:Silvia Carloni、Dirk E. De Vos、Pierre A. Jacobs、Raimondo Maggi、Giovanni Sartori、Raffaella Sartorio
DOI:10.1006/jcat.2001.3439
日期:2002.1
The synthesis of carbamates 3 and unsymmetrical alkyl carbonates 5 by reaction of diethyl carbonate with aliphatic amines or alcohols has been realized by using as heterogeneous catalyst a hybrid organic–inorganic material prepared by anchoring TBD to MCM-41 silica. Products are obtained in high yield and very good selectivity and the solid catalyst can be recovered simply by filtration and reused