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An expeditious and consistent procedure for tetrahydrofuran (THF) drying and de...
Simas,Alessandro B. C.; Pereira,Vera L. P.; Barreto Jr.,Cleber B.; Sales,Daniel L. de; Carvalho,Leandro L. deDespite the availability of alternative methods for drying tetrahydrofuran (THF), the use of the still apparatus, wherein a THF solution containing Na-bezophenone ketyl is heated to reflux, remains widespread. We herein propose a set of procedures to solve the problems usually faced in applying this drying technique. Moreover, a discussion is made on the chemical knowledge underlying such procedures. Safety and...
In vitro tests of suitability of bacteriocin-producing lactic acid bacteria, as...
Tomé, Elisabetta; Pereira, Vera L.; Lopes, Carla I.; Gibbs, Paul A.; Teixeira, Paula C.The objectives of this study were to ascertain the in vitro potential of nine bacteriocin-producing lactic acid bacteria (LAB) strains, isolated from vacuum-packaged cold-smoked salmon (CSS), for possible use as biopreservative cultures against Listeria monocytogenes. The antilisterial activity of cultures’ supernatants was assessed at 0.5%, 3.0% and 5.0% w/v of salt, at 5ºC, 10ºC and 25ºC both in aerobic and a...
A new route to keto and alkyl derivatives of (R)-carvone via diastereoselective...
Costa,Jeronimo S.; Freire,Bruno S.; Moura,André L. S.; Pereira,Vera L. PatrocinioThe reactivity and diastereoselectivity of conjugate addition of different nitronates ions to (R)-carvone was systematically studied. The Michael adducts 2a-e were obtained in good yield and 3,2-cis-3,5-trans selectivity. The nitroadducts 2b,c were transformed via Nef reaction into (R)-carvone ketone derivatives 9,10 and nitroadducts 2b,d led to (R)-carvone alkylated derivatives 11,12, via a denitration reaction.
Tendências tecnológicas de polietilenos e polipropileno através da prospecção e...
Antunes,Adelaide M. S.; Giannini,Roberto G.; Borschiver,Suzana; Pereira,Vera L. S. B.O presente artigo fornece uma avaliação estratégica da tecnologia de produção de polímeros à base de etileno, principalmente o polietileno, bem como dos polímeros a base de propileno, principalmente o polipropileno, mostrando a tendência em relação a novos produtos, mercados e de concorrentes, com base em informações extraídas de documentos de patentes publicados a partir de 1990. O termo documento de patente a...
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