Trichloroisocyanuric Acid: An Alternate Green Route for the Transformation of Alkenes into Epoxides

A argila comercial brasileira Bentonit Brasgel ® foi caracterizada por análises química e textural, DRX e RMN no estado sólido de 27 Al and 29 Si, que indicaram a presença de quartzo-α e esmectita como argilo-minerais. Essa argila se mostrou um catalisador eficiente para a conversão de alquenos nos respectivos epóxidos através da reação com iodo/água seguida de adição de KOH em hexano in situ (80-91 %). Resultados similares foram obtidos usando-se Bentonit Brasgel™ intercalada com Ag(I).The commercial Brazilian clay Bentonit Brasgel™ was characterized by chemical and textural analyses, XRD, and 27 Al and 29 Si MAS-NMR, that indicated the presence of α-quartz and smectite as clay-minerals. This natural clay proved to be an efficient catalyst for the conversion of alkenes into epoxides by the reaction with iodine/water followed by in situ addition of KOH in hexane (80-91 % yield). Similar results were obtained with Bentonit Brasgel™ intercalated with Ag(I). Keywords: epoxide, coiodination, iodohydrin, clay, alkenes IntroductionNowadays, the search for cleaner process is one of the major challenges in modern chemical industries. 1 Moreover, the high versatility, low-cost and gain in yield/ selectivity turn clays very attractive catalysts in the green chemistry point of view as they are reusable and present minimal environmental impact. 2 Within this context, the use of clays and clay-minerals in synthetic organic chemistry has increased enormously in the last years. 3 Epoxides are useful compounds in synthetic organic chemistry 3 and the interest for these valuable compounds has increased with the discovery of some biological activities related to the oxirane ring. 5 There are several efficient methodologies for the preparation of epoxides, for example: the oxidation of alkenes with peracids and the cyclization of halohydrins with bases are the most employed. 4 Peracids and analogues have been used to prepare epoxides; even though, these reagents must be carefully manipulated, due to their tendency to explosion. 6 The epoxidation of alkenes with molecular O 2 or H 2 O 2 seems to be very attractive, but it is expensive because it needs a metal-based catalytic system 7 or zeolites 8 and frequently suffers from formation of undesirable oxygenated by-products. Metal-free epoxidation of alkenes with H 2 O 2 occurs in the presence of some auxiliaries (nitriles, carbodiimides, etc) which convert hydrogen peroxide to a more active oxidant. 9 On the other hand, halohydrins are widely used in epoxide synthesis in both laboratorial and industrial scale. 10 The cohalogenation 11 with water (halogenation of alkenes in aqueous solutions) is an effective way to prepare these intermediates. 12 Although this methodology is effective, the handling and manipulation of toxic and corrosive halogens is problematic (especially in large-scale), then the search for alternative sources of electrophilic halogen is of great interest. 13 1510A New Environmentally Friendly Clay Catalyst for One-pot Coiodination J. Braz. Chem. Soc.Recently, we...

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A new environmental friendly clay catalyst for one-pot coiodination and epoxidation of alkenes

Bernini

Aguiar

2007

“…The products were characterized by spectroscopic methods and, wherever possible, by coinjection in HRGC with authentic commercial samples or prepared by an alternative route. 13 In summary, NCSac and NBSac are alternative and attractive reagents to perform halogenation of electron rich aromatic compounds and cohalogenation of alkenes. Furthermore, the reaction conditions are simple, safe and these halosaccharins are easily prepared by commercial sodium saccharin.…”

Section: Resultsmentioning

confidence: 99%

N-Chloro and N-bromosaccharins: valuable reagents for halogenation of electron rich aromatics and cohalogenation of alkenes

Souza¹,

Silva²,

Mattos³

2003

Self Cite

acetona aquosa fornecem as respectivas haloidrinas.N-Chloro-and N-bromosaccharins react with electron rich aromatic compounds (anisole, acetanilide, N,N-dimethylaniline) producing halogenated compounds. The reaction with N-bromosaccharin gives para-substituted compounds only, whereas N-chlorosaccharin produces orto and para mixtures (para isomer predominantly, ca. 4-5 : 1). The reactions of the N-halosaccharins with alkenes (cyclohexene, styrene, α-methylstyrene, and 1-hexene) give the corresponding halohydrins.

“…7 This compound is extensively used as a disinfectant agent for swimming pools (algicide and bactericide). 8 Presently, TCI is also widely employed as an effective chlorinating reagent for various chemical reactions, such as the α-chlorination of carbonyl derivatives, 9 the production of nitriles from amines, 10 the halogenation and epoxidation of alkenes, 11 and the chlorination of aromatic systems, 5,12 among others; extensive reviews on the reactions of TCI have been offered by Tilstan and Weinmann, 4 Cunha and Ferreira 13 and Mendonça and Mattos. 14 Figure 1 shows the chemical structures of these molecules.…”

Section: Introductionmentioning

confidence: 99%

Using Bar Infrared Spectra and Coincidence Indexes to Study the Diversity of Solid Cyanuric Acid Structures

Nilo¹,

Simões²,

Neto³

2018

A general method was developed for studying the diversity of individuals in a population based on the diversity of infrared spectra of solid cyanuric acid analytes obtained from various reactions of trichlorocyanuric acid. This method first generates infrared bar spectra for the analytes and then measures the coincidence and continence among pairs of the spectral peaks via confrontation matrices. Class markers are established to characterize analyte classes. Possible correlations among the employed reaction conditions and the nature of the produced solids, which are based on their infrared bar spectra, are discussed. The method of coincidence may be useful for characterizing polymorphs, particularly those of active pharmaceutical ingredients (APIs). The method may also be extended to define the homogeneity of solid analytes. The ANALIN module of the ANALOR software suite running on a dBase platform is used to generate the bar infrared spectra and to handle all calculations.