Xi:Irritant;
1459-93-4Relevant articles and documents
Synthesis of isophthalates from methyl coumalate
Kraus, George A.,Wang, Shuai
, p. 56760 - 56763 (2017)
Methyl coumalate reacts with enol ethers to form stable adducts which can be converted into isophthalates in good to excellent yields. Alkyl vinyl ethers afford higher yields of isophthalates than enol silyl ethers. The adduct of the enol silyl ether of acetophenone with methyl coumalate reacted with PTSA to produce a styryl coumalate.
Surface-enhanced infrared absorption of DMIP on gold-germanium substrates coated by self-assembled monolayers
Domingo,García-Ramos,Sánchez-Cortés,Aznarez
, p. 419 - 427 (2003)
Gold islands coated with self-assembled monolayers of three enough different thiols - thiophenol, propanethiol and octadecanethiol - are shown to enable the detection of molecules without polar groups, such as dimehylisophthalate (DMIP), using Surface enhanced infrared absorption (SEIRA). Binding of thiols was studied using SERS and SEIRA. The careful comparison of the transmission and p-polarized external reflection SEIRA spectra of DMIP taken using the modified substrates, with the corresponding spectra taken on the uncoated gold-Ge and bare Ge and CaF2 surfaces, has allowed to elucidate the role played by the underlayer substrate and the different thiols in the total observed enhancement effect. Furthermore, the DMIP orientation with respect to the gold surface for each thiol-coating has also been deduced, confirming that the surface selection rule in our case applies both to reflection and transmission SEIRA spectra. No SERS spectra of DMIP, either on the modified or on the uncoated gold substrates, were revealed.
A supramolecular porous material comprising Fe(ii) mesocates
Wilson, Benjamin H.,Scott, Hayley S.,Qazvini, Omid T.,Telfer, Shane G.,Mathonière, Corine,Clérac, Rodolphe,Kruger, Paul E.
, p. 13391 - 13394 (2018)
The dinuclear mesocate [Fe2L3](BF4)4, 1, is a supramolecular building block for a microporous material. Structural analysis reveals that extensive noncovalent interactions in the solid state generate a 3D framework with microporous channels. These channels are permanently accessible to incoming guest molecules and adsorption isotherms demonstrate that the material has a high selectivity for CO2 over N2
Electrochemical Reduction of Pyridine- and Benzene-Substituted n-Alkyl Esters and Thioic S-Esters in Acetomtrile
Webster, Richard D.,Bond, Alan M.
, p. 1779 - 1787 (1997)
Bulk controlled potential electrolysis experiments have been performed on a wide range of n-alkyl- substituted esters and thioic S-esters of pyridine and benzene in dry acetonitrile with tetraalkylammonium salts as the supporting electrolyte. In most cases, the bulk one-electron reduction of oxygen esters results in unstable or semistable radicals being formed that decompose via loss of the alkyl radical to leave the carboxylate anion in high yield (ca. 70-100%). Benzoate and dinicotinate esters are the exception to this where the final decomposition products are numerous and complicated. For the thioic S-esters, two types of decomposition mechanism have been identified as operating depending on the stability of their anion radicals. Thioic S-ester radical anions that are very unstable (lifetimes in the order of several milliseconds) decompose with loss of the thiolate ion to leave a neutral acyl radical that undergoes aromatic substitution reactions with other acyl radicals to form, among other products, γ-lactones. Thioic S-esters radical anions that are stable for many minutes to hours ultimately decompose via reaction with molecular oxygen to form carboxylate anions.
Novel Isophthalohydrazide-cDB24C8 cryptand derivative for the selective recognition of fluoride ion: An experimental and DFT study
Bora, Sankar Jyoti,Dutta, Rakesh,Kalita, Dhruba Jyoti,Chetia, Bolin
, p. 225 - 231 (2018)
A highly selective and sensitive novel Isophthalohydrazide-cDB24C8 cryptand derivative was developed for fluoride recognition at a very low concentration of 2.31 × 10?10 M. The binding was established by UV–Vis, fluorescence and 1H NMR titration. The receptor formed very strong H-bonded complex with fluoride, furnished a sharp new UV–Vis absorption peak at 280 nm which was also supported by the DFT-study. The fluorescence emission spectra showed large quenching up to 79.13% upon addition of fluoride.
Carboxyl Methyltransferase Catalysed Formation of Mono- and Dimethyl Esters under Aqueous Conditions: Application in Cascade Biocatalysis
Ashbrook, Chloe,Carnell, Andrew J.,Goulding, Ellie,Hatton, Harry,Johnson, James R.,Kershaw, Neil M.,McCue, Hannah V.,Rigden, Daniel J.,Ward, Lucy C.
supporting information, (2022/02/21)
Carboxyl methyltransferase (CMT) enzymes catalyse the biomethylation of carboxylic acids under aqueous conditions and have potential for use in synthetic enzyme cascades. Herein we report that the enzyme FtpM from Aspergillus fumigatus can methylate a broad range of aromatic mono- and dicarboxylic acids in good to excellent conversions. The enzyme shows high regioselectivity on its natural substrate fumaryl-l-tyrosine, trans, trans-muconic acid and a number of the dicarboxylic acids tested. Dicarboxylic acids are generally better substrates than monocarboxylic acids, although some substituents are able to compensate for the absence of a second acid group. For dicarboxylic acids, the second methylation shows strong pH dependency with an optimum at pH 5.5–6. Potential for application in industrial biotechnology was demonstrated in a cascade for the production of a bioplastics precursor (FDME) from bioderived 5-hydroxymethylfurfural (HMF).
FLOW CHEMISTRY SYNTHESIS OF ISOCYANATES
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Paragraph 0175; 0250-0252, (2021/06/22)
The disclosure provides, inter alia, safe and environmentally-friendly methods, such as flow chemistry, to synthesize isocyanates, such as methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetramethylxylene diisocyanate.
Br?nsted acid-catalyzed chlorination of aromatic carboxylic acids
Yu, Zhiqun,Yao, Hongmiao,Xu, Qilin,Liu, Jiming,Le, Xingmao,Ren, Minna
supporting information, p. 685 - 689 (2021/04/09)
The chlorination of aromatic carboxylic acids with SOCl2 has been effectively performed by reacting with a Br?nsted acid as the catalyst. Based on this discovery, an efficient catalytic method that is cheaper than traditional catalytic methods was developed. 20 substrates were chlorinated offering excellent yields in a short reaction time. And the SOCl2/Br?nsted acid system has been used in a larger scale preparative reaction. A dual activation mechanism was proposed to prove the irreplaceable system of SOCl2/Br?nsted acid.
Mild Copper-Catalyzed Addition of Arylboronic Esters to Di- tert -butyl Dicarbonate: An Easy Access to Methyl Arylcarboxylates
Xu, Jin-Di,Su, Xiao-Bo,Wang, Cai,Yao, Li-Wei,Liu, Jing-Hui,Hu, Guo-Qin
supporting information, p. 833 - 837 (2021/02/26)
An efficient copper-catalyzed addition of arylboronic esters to (Boc) 2O was developed. The reaction can be conducted under exceedingly mild conditions and is compatible with a variety of synthetically relevant functional groups. It therefore represents a useful alternative route for the synthesis of methyl arylcarboxylates. A preliminary mechanistic study indicated the involvement of an addition-elimination mechanism.
Method for coproducing methyl benzoic acid Process for the production of methyl benzoates and diesters of phthalic acids
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Paragraph 0125-0175, (2021/02/09)
The invention discloses a coproduction method of methylbenzoic acid, methyl benzoate and benzenedicarboxylic acid diester. The method comprises the following steps: (1) continuously introducing xylene, a catalyst and oxygen-containing gas into an oxidation reactor for a reaction, and controlling oxygenic concentration in the tail gas to not exceed 5% by controlling introduction amount of the oxygen-containing gas to obtain an oxidation reaction liquid; (2) feeding the obtained oxidation reaction liquid into a predistillation tower for distillation separation to obtain a low-boiling-point component and a predistillation tower bottom liquid; (3) feeding the predistillation tower bottom liquid into a distillation tower for distillation to obtain a methylbenzoic acid product and a distillationtower bottom liquid; (4) mixing the distillation tower bottom liquid and alcohol for an esterification reaction, and controlling the reaction endpoint to be lower than 0.5wt% of the content of methylbenzoic acid to obtain an esterification reaction liquid; (5) performing distillation separation on the obtained esterification reaction liquid to obtain methyl benzoate and benzenedicarboxylic acid diester products. The method has the advantages that the process is simple, equipment investment is low, and the method is environmentally friendly and has good comprehensive economic benefits.
