- Clean preparation method of 4-hydroxymethylthiazole and its intermediate
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The invention discloses a clean preparation method of 4-hydroxymethylthiazole and its intermediate. The clean preparation method includes, taking compound I as an example, the steps of in a solvent, subjecting compound IV and an alkali metal hypohalite to
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Paragraph 0074-0075
(2019/04/06)
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- Gas-Phase Oxidation of Allyl Acetate by O3, OH, Cl, and NO3: Reaction Kinetics and Mechanism
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Allyl acetate (AA) is widely used as monomer and intermediate in industrial chemicals synthesis. To evaluate the atmospheric outcome of AA, kinetics and mechanism of its gas-phase reaction with main atmospheric oxidants (O3, OH, Cl, and NO3) have been investigated in a Teflon reactor at 298 ± 3 K. Both absolute and relative rate methods were used to determine the rate constants for AA reactions with the four atmospheric oxidants. The obtained rate constants (in units of cm3 molecule-1 s-1) are (1.8 ± 0.3) × 10-18, (3.1 ± 0.7) × 10-11, (2.5 ± 0.5) × 10-10, and (1.1 ± 0.4) × 10-14, for reactions with O3, OH, Cl, and NO3, respectively. While results for reactions with O3, OH and Cl are in good agreement with previous studies, the kinetics for the reaction with NO3 is reported for the first time in this study. On the basis of determined rate constants, the tropospheric lifetimes of AA are ρO3 = 9 days, ρOH = 5 h, ρCl = 5 days, ρNO3 = 2 days. On the basis of the products study, reaction mechanisms for these oxidations have been proposed and the reaction products were detected using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) and Fourier transform infrared spectroscopy (FTIR). Results show that the main products formed in these reactions are carbonyl compounds. In particular, 2-oxoethyl acetate was detected in all four AA oxidation reactions. Compared to previous studies, several new products were determined for reactions with OH and Cl. These results form a set of comprehensive kinetic data for AA reactions with main atmospheric oxidants and provide a better understanding of the degradation and atmospheric outcome of unsaturated acetate esters in the troposphere, during both daytime and nighttime.
- Wang, Shuyan,Du, Lin,Zhu, Jianqiang,Tsona, Narcisse T.,Liu, Shijie,Wang, Yifeng,Ge, Maofa,Wang, Wenxing
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p. 1600 - 1611
(2018/02/22)
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- Tropospheric chemical degradation of vinyl and allyl acetate initiated by Cl atoms under high and low NOx conditions
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The products of the reactions of Cl atoms with vinyl acetate (VA) and allyl acetate (AA) have been investigated in a 1080 L chamber using in situ FTIR. The experiments were performed at 296 K and atmospheric pressure of synthetic air in the presence and in the absence of NOx. For the reaction of Cl with VA in the presence of NOx formic acetic anhydride, acetic acid and formyl chloride are the major reaction products. In the absence of NOx, the yields of these products are significantly reduced and formation of the carbon-chain-retaining compound CH3C(O)OC(O)CH2Cl is observed. For the reaction of Cl with AA in the presence of NOx acetoxyacetaldehyde and formaldehyde were observed as the main products. In contrast, without NOx, the observations support that the major reaction pathway is the formation of the carbon-chain-retaining compound CH3C(O)OCH2C(O)CH2Cl. The reaction mechanisms leading to the products are discussed. The formation of the high yields of formyl chloride and formaldehyde in the reactions of Cl with VA and AA, respectively, are at odds with currently accepted mechanistic pathways.
- Blanco, María B.,Bejan, Iustinian,Barnes, Ian,Wiesen, Peter,Teruel, Mariano A.
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p. 48154 - 48163
(2015/06/16)
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- A mild, convenient, and inexpensive procedure for conversion of vinyl halides to α-haloketones
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Treatment of a vinyl chloride with commercially available aqueous sodium hypochlorite solution in a 2:5 mixture of acetic acid/acetone at 0 °C for about 1 h cleanly leads to the corresponding α-chloroketone. Similarly, if a vinyl bromide is exposed to sodium hypobromite (freshly prepared from bromine and sodium hydroxide) at 0 °C in 2:5 acetic acid/acetone as solvent, an α-bromoketone is produced. This methodology has been applied to a number of vinyl chlorides and vinyl bromides, and the transformations generally proceed in high yields. The mild reaction conditions are compatible with a variety of functional groups including amides, esters, and imines.
- VanBrunt, Michael P.,Ambenge, Reuben O.,Weinreb, Steven M.
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p. 3323 - 3326
(2007/10/03)
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- 2-GUANIDINO-4-HYDROXYMETHYL-THIAZOLE AND DERIVATIVES THEREOF
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A compound of the formula: STR1 wherein R is hydrogen, C. sub.1-C. sub.5 alkanoyl or substituted sulfonyl, which is useful as a synthetic intermediate to 2-guanidino-4-[2-(formamido)ethylthiomethyl] thiazole, histamine H 2 receptor antagonist.
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