- Synthesis and hydrolysis behavior of side-chain functionalized norbornenes
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The stabilities of various functionalized norbornenes that are monomers for the ring-opening metathesis polymerization (ROMP) in aqueous solution were evaluated toward hydrolysis under a range of temperatures (37, 60, and 80 °C) and pH values (3-9). All monomers contain hydrolyzable linkages to pendant functional groups, and conclusions were drawn relating to how the chemical diversity of these pendant functional groups, in accordance with the pH and temperature variations, affect hydrolysis of the aforementioned linkages. The hydrolysis was monitored by reverse phase HPLC analysis, and/or NMR spectroscopy. As expected, monomers containing ester linkages were fairly labile at higher pH values, while acetal-based linkers were cleaved at lower pH values. β-Amino ester groups experienced a significant increase in hydrolysis rate, while carboxylic acid-containing monomers did not follow any clear trend. Saccharide-containing monomers exhibited unique behaviors for various pH values and temperature ranges.
- Carlise, Joseph R.,Kriegel, Robert M.,Rees Jr., William S.,Weck, Marcus
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- Substituted diether diols by ring-opening of carbocyclic and stannylene acetals
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Reduction of malonaldehyde bis(ethylene and propylene acetals) with borane or monochloroborane produces diether diols 1 and 2 in high yield. Similar reduction of glyoxal his(ethylene acetals) has only limited utility for the preparation of tetrasubstituted triethylene glycols 3. Organotin chemistry is complementary: stannylene acetals prepared from disubstituted vicinal diols can be alkylated with half an equivalent of 1,2-dibromoethane to produce tetrasubstituted triethylene glycols 3, or with two equivalents of 2-chloroethanol to produce disubstituted triethylene glycols 4.
- Martinez-Bernhardt, Rolando,Castro, Peter P.,Godjoian, Gayane,Gutierrez, Carlos G.
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- CO2atmosphere enables efficient catalytic hydration of ethylene oxide by ionic liquids/organic bases at low water/epoxide ratios
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The development of an efficient and low-cost strategy for the production of monoethylene glycol (MEG) through hydration of ethylene oxide (EO) at low H2O/EO molar ratios is an important industrial challenge. We have established that by using CO2as the reaction atmosphere, hydration of EO can be achieved at a low H2O/EO ratio of 1.5?:?1 along with high yields (88-94%) and selectivities (91-97%) of MEG catalyzed by binary catalysts of ionic liquids and organic bases. The results are significantly better than those of experiments conducted under an atmosphere of N2. Isotope labeling experiments revealed that CO2had altered the reaction pathway and participated in the reaction, in which cycloaddition of EO with CO2occurred first followed by the hydrolysis of ethylene carbonate (EC) to generate MEG and recover CO2. The ionic liquids and organic bases synergistically catalyzed the one-pot two-step reaction. DFT calculations confirmed that this route is more kinetically favorable compared to the pathway of direct epoxide hydration.
- Ding, Tong,Gao, Guohua,Xia, Fei,Yuan, Huixia,Zha, Jinyin,Zhang, Dawei,Zhang, Jingshun
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supporting information
p. 3386 - 3391
(2021/05/25)
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- Nanotitania catalyzes the chemoselective hydration and alkoxylation of epoxides
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Glycols and ethoxy– and propoxy–alcohols are fundamental chemicals in industry, with annual productions of millions of tons, still manufactured in many cases with corrosive and unrecoverable catalysts such as KOH, amines and BF3?OEt2. Here we show that commercially available, inexpensive, non–toxic, solid and recyclable nanotitania catalyzes the hydration and alkoxylation of epoxides, with water and primary and secondary alcohols but not with phenols, carboxylic acids and tertiary alcohols. In this way, the chemoselective synthesis of different glycols and 1,4–dioxanones, and the implementation of nanotitania for the production in–flow of glycols and alkoxylated alcohols, has been achieved. Mechanistic studies support the key role of vacancies in the nano–oxide catalyst.
- Ballesteros–Soberanas, Jordi,Leyva–Pérez, Antonio,Martínez–Castelló, Aarón,Oliver–Meseguer, Judit,Tejeda–Serrano, María
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- Photocatalytic Degradation of Hexaethylene Glycol
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Abstract: Polyethylene glycol (PEG) photodegradation was studied in water under UV irradiation in the presence of catalytic amount of TiO2 using hexaethylene glycol as a model compound. Full conversion was achieved in 7 h with an average quantum yield around 1%. Formic acid was found to be the main intermediate and was slower to oxidize into CO2 (traces remains after 24 h). The other intermediates [lower PEG, oxidized PEG (formates, aldehydes and acids, acetic acid)] of the photodegradation have also been identified and quantified. A mechanism based on previous literature but also taking into account these new observations is proposed. Graphical Abstract: [Figure not available: see fulltext.].
- Simangoye Ngobissi, Drocilia Ednah,Soufi, Jihène,Vanoye, Laurent,Richard, Dominique
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p. 1608 - 1614
(2017/08/29)
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- Catalytic hydration process for production of ethylene glycol
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The invention relates to a method for producing glycol by catalytic hydration, which solves the problems of high equipment investment and high energy consumption existed in the direct hydration production of glycol in prior art. The method comprises the following steps: a) a material flow 1 containing ethylene oxide and water is introduced in a catalytic hydration reaction unit R, a material flow 6 containing glycol can be obtained after the reaction; b) the material flow 6 is introduced in a feed preheater of an evaporation tower D3, and preheating is carried out to obtain a material flow 7; c) the material flow 7 is introduced in the center part of the evaporation tower, after being separated, a glycol aqueous solution 8 is obtained at the bottom of the evaporation tower, and a steam material flow 9 is obtained at the top of the tower; and d) the material flow 9 is divided into a material flow 10 and a material flow 11; the material flow 10 is introduced in the feed preheater of the evaporation tower D3; and the material flow 11 is introduced into a subsequent flow. The technical scheme can better solve the problems, and the method of the invention can be used in an industrial production for producing glycol by ethylene oxide catalytic hydration.
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Paragraph 0035-0042
(2017/02/24)
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- Bis-TEGylated poly(p-benzamide)s: Combining organosolubility with shape persistence
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The synthesis of perfectly planar, bis-substituted aromatic polyamides is reported herein. With highly flexible triethylene glycol chains attached and conformational restriction through intramolecular, bifurcated hydrogen bonds these are among the most shape-persistent yet organo-soluble polymers to date. Starting from 4-nitrosalicylic acid, our group developed a route to phenyl-2,5-bis-TEGylated aminobenzoate, which could be polymerized by addition of lithium bis(trimethylsilyl)amide (LiHMDS). Since this technique has not been applied to step-growth polycondensations of polyaramides so far, the influence of two different solvents and an N-protective group was investigated. Therefore, substituted phenyl aminobenzoate derivatives carrying a free amine or an N-protective group have been polymerized. Additionally, the tendency for self-assembly of the readily soluble bis-TEGylated poly(p-benzamide) was observed by transmission electron microscopy (TEM) in the dried state. Dynamic light scattering (DLS) measurements of chloroform solutions did not indicate the formation of aggregates. Thus, intermolecular interactions, which other aromatic polyamides typically exhibit, are prevented. The access to bis-substituted, entirely rigid poly(p-benzamide)s via this new polycondensation method paves the way for exciting new structures in materials science and supramolecular chemistry.
- Schulze, Maren,Michen, Benjamin,Fink, Alke,Kilbinger, Andreas F. M.
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p. 5520 - 5530
(2013/08/23)
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- Two-Stage, Gas Phase Process for the Manufacture of Alkylene Glycol
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A two-stage, gas phase process for manufacturing alkylene glycol (e.g., ethylene glycol) from an alkene (e.g., ethylene), oxygen and water, the process comprising the steps of: (A) Contacting under gas phase, oxidation conditions gaseous alkene and oxygen over a heterogeneous oxidation catalyst to produce a gaseous oxidation product comprising alkylene oxide, water and unreacted alkene;(B) Contacting under gas phase, hydrolysis conditions the gaseous oxidation product of (A) with added water over a heterogeneous hydrolysis catalyst to produce a gaseous alkylene glycol and unreacted alkene; and(C) Recycling the unreacted alkene of (B) to (A). The hydrolysis catalyst is selected from the group consisting of hydrotalcites, metal-loaded zeolites, phosphates, and metal-loaded ion-exchanged molecular sieves. The process improves over the conventional two-stage process by the elimination of steps and equipment to recover and refine alkylene oxide, the use of less water in the hydrolysis reaction, and the elimination of the entire evaporation train used in the recovery of alkylene glycol.
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Page/Page column 8
(2010/03/02)
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- Process for the preparation of alkylene glycols
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Disclosed is a process for the preparation of alkylene glycols from the corresponding alkylene oxide, such as ethylene glycol from ethylene oxide, in the presence of water, a catalyst and, optionally, carbon dioxide. The catalyst contains an amphoteric compound, such as such as (ethylenedinitrilo) tetraacetic acid (EDTA). These befunctional compounds have both acid and base moieties. Preferably, a compound useful in the present invention forms a buffered solution in water, i.e., the acid and base moieties do not completely disassociate. The pH of the buffered solution should be 2-10, preferably 5-10, more preferably 4-9. A compound useful in the present invention is preferably organic with the base moiety and the acid moiety being separated by one to four carbon atoms.
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Page/Page column 3-4
(2008/06/13)
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- Process for preparing alkylene glycols
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The invention relates to a process for preparing alkylene glycols by hydration of alkylene oxides in the presence of polyalkylene glycol dialkyl ethers of the formula [in-line-formulae]R1—O—[—(CH2CH2O)m(CH(CH3)CH2)—O]n—R2 [/in-line-formulae] in which m=0-100, n=0-100, where n+m is at least equal to 1, R1 is a C1- to C6-alkyl radical, R2 is a C1- to C6-alkyl radical, where R2 may be different from R1, with the proviso that for at least 50 mol % of the polyalkylene glycol dialkyl ether m+n is greater than or equal to 11.
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Page/Page column 2
(2008/06/13)
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- WATER AND SOLVENT FREE PROCESS FOR ALKOXYLATION
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A water and solvent free process for alkoxylation of mixed polyhydric compounds comprising at least two different polyhydric compounds each having at least 3 hydroxyl groups is disclosed. The process comprises that at least one polyhydric compound (I) has a melting point exceeding applied alkoxylation temperature and that at least one polyhydric compound (II) has a melting point below said alkoxylation temperature. Compound (II) is used as solution medium and/or as carrier for said compound (I). Yielded mixed polyhydric alkoxylate has a combined monoalkylene, dialkylene and trialkylene glycol content of less than 0.5% by weight.
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Page/Page column 9
(2008/06/13)
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- Selective cleavage of O-(dimethoxytrityl) protecting group with sodium periodate
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Sodium periodate in aqueous organic solvents selectively removes, under mild reaction conditions, the O-(dimethoxytrityl) protecting group. Selectivity of the cleavage was studied using the nucleoside derivatives protected by various types of groups commonly used in nucleoside and nucleotide chemistry.
- Rejman, Dominik,Kralikova, Sarka,Tocik, Zdenek,Liboska, Radek,Rosenberg, Ivan
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p. 502 - 508
(2007/10/03)
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- Strong solid base reagents and catalysts based on carbonaceous supports
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Porous carbons are shown to have very high affinities for basic hydroxides, fluorides and oxides. The resulting materials are demonstrated to be strong base catalysts for solution and gas phase reactions. They can also be used as stoichiometric reagents to generate carbanions in solution. When the solid is filtered off and the solution temperature raised to initiate the reaction, very selective Michael addition reactions occur.
- Drago, Russell S.,Jurczyk, Krzysztof
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p. 927 - 930
(2007/10/03)
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- Relaxation Kinetics and Infrared Spectra of the Complexation of Lithium Ion by Triethylene Glycol and by Tetraethylene Glycol in Acetonitrile
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Ultrasonic absorption relaxation spectra are reported covering the frequency range ca. 1-500 MHz for the complexation of LiClO4 by the open-chain polyethers triethylene glycol (EG3) and tetraethylene glycol (EG4) in acetonitrile at 25 deg C and at a molar ratio R = / or R = / = 1.The ultrasonic spectra can be described by the sum of two Debye relaxation processes which were interpreted according to the Eigen-Winkler mechanism Li+ + EG Li+...EG Li+EG (Li+EG) (where EG denotes either EG3 or EG4), giving the rateconstants k1, k-1, k2, and k-2.The first step is taken to be a preequilibrium step for which K0 is calculated from classical statistical theory.The rate constants are compared with those of the corresponding process involving triglyme and poly(ethylene oxide) (PEO) previously reported.Infrared data for the 3800-3200-cm-1 region show a shift of 70 cm-1 to lower energy, indicating a strong interaction between the ethanolic oxygen of EG3 and the Li+ ion.
- Cobranchi, Daryl P.,Garland, Ben A.,Masiker, Marilyn C.,Eyring, Edward M.,Firman, Paul,Petrucci, Sergio
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p. 5856 - 5865
(2007/10/02)
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- Carbonylation of diols and their ethers and esters with ruthenium catalysts: synthesis of lactones and hydroxyacids ethers and esters
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Diols and their formic or acetic esters can be carbonylated to give lactones or the corresponding hydroxyacid ester or ethers in the presence of carbonylruthenium iodide systems. -/alkyl or metal iodide, at a temperature of 200 deg C and CO pressure of 10-20 MPa.The reaction in the case of 1,3-propanediol gives γ-butyrolactone, with a selectivity of 60-70 percent.Side reactions of homologation to 1,4-butanediol derivatives and hydrogenolysis to n-propyl derivatives by H2 produced by the water gas shift reaction (WGSR) also occur, together with acid-catalyzed dehydration to give linear polypropylene glycols, α,ω-diols with more than 3 carbon atoms in the chain preferentially give hydroxyacid esters and ethers.The cyclic ether by-products and linear polyether by-products can be further activated and carbonylated under the reaction conditions to give lactones or hydroxy-acid derivatives thus increasing the total yield of carbonylation products.The formation of H2 by WGSR involving water produced by the acid-catalyzed dehydration reactions, and the subsequent hydrogenolysis and homologation reactions cannot be avoided.
- Braca, G.,Sbrana, G.,Galletti, A. M. Raspolli,Berti, S.
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p. 245 - 258
(2007/10/02)
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- The Influence of Cation Binding on the Kinetics of the Hydrolysis of Crown Ether Acetals
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The rate of hydrogen ion-catalysed hydrolysis of crown ether acetals in 60:40 (v/v) dioxan-water is found to be strongly decreased by the addition of alkali and alkaline earth metal chlorides having cations of appropriate size to be complexed by the substrate ring.The compounds studied are the monoacetals CH3CH(OCH2CH2)xO with x=1-8.The dependence of the initial rate of formation of acetaldehyde on metal-ion concentration is expressed in terms of (i) the equilibrium constant for complex formation, (ii) the influence of the bound cation on the rate constant, and (iii) an electrolyte effect.A curve-fitting procedure is used to derive the parameters governing the first two of these effects.The equilibrium constants are large and cannot be evaluated with any precision, but a fair estimate of the influence of the guest cation on the rate can be obtained.This effect is explicable by the electrostatic repulsion between the cationic charges of the metal ion and the proton added to the acetal in the first step of the hydrolysis.The size of the effect requires the values of the effective relative permittivity of the space between the charges to be close to that of the bulk solvent.
- Baker, David S.,Gold, Victor,Sghibartz, Cristian M.
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p. 1121 - 1128
(2007/10/02)
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