A multi-syringe flow system for monitoring moderately fast chemical reactions

• Autor(a) principal: Cerdà,Víctor
• Data de Publicação: 2012
• Outros Autores: Ubide,Carlos, Zuriarrain,Juan
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532012001100005
• topic: multi-syringe flow analysis; zone stopping; bromine generation; bromine-salicylic acid reaction

The zone stopping mode of the multi-syringe flow injection analysis (MSFIA) technique was exploited for monitoring of moderately fast reactions. The performance of MSFIA relies on the use of both efficient mixing chambers (cross unions) and a motor that propels a bar pushing up a number of syringes to provide dead times of about 20 ms. The well-known bromine generation from a bromate-bromide mixture in acidic medium is used as chemical system. The rate constant found (3.9 ± 0.7 mol-3 L³ s-1) agrees to values given in literature. Reagents in statu nascendi were also produced and used at once. As an example, bromine was generated and immediately used in the bromination of salicylic acid, avoiding the handling of dangerous chemicals; the rate constant found (5.5 ± 0.8 mmol-1 L s-1) agrees to the values given in literature. The methodology is an easy alternative to the traditional stopped-flow apparatus used in moderately fast reactions.