Hydrobromic acid

About: Hydrobromic acid is a research topic. Over the lifetime, 1781 publications have been published within this topic receiving 14698 citations. The topic is also known as: HBr & Hydrobromic acid.

Characterisation of reduced graphene oxide: Effects of reduction variables on electrical conductivity

Abstract: Graphene is a useful material because of its excellent electronic and physical properties. Graphene and its derivatives can be used as functional reinforcements in polymers for applications, such as sensors, flexible devices, packaging, and functional nanocomposites. This article focuses on the synthesis, reduction using three different reductants (hydrobromic acid, hydrazine hydrate and hydroiodic acid) and characterisation (using Raman spectroscopy X-ray diffraction and X-ray photoelectron spectroscopy) of reduced graphene oxide in order to systematically maximise its electrical conductivity and identify a structure with physical properties which possesses higher electrical conductivity. Results for reduced graphene oxide film that has been reduced with hydroiodic acid show an electrical conductivity of 103.3 S cm−1 with better flexibility compared to rGOs reduced by hydrobromic acid and hydrazine hydrate.

Production of cellulose nanocrystals using hydrobromic acid and click reactions on their surface

Abstract: Cellulose nanocrystals (CNCs) were prepared by acidic hydrolysis of cotton fibers (Whatman #1 filter paper). In our efforts to select conditions in which the hydrolysis media does not install labile protons on the cellulose crystals, a mineral acid other than sulfuric acid (H2SO4) was used. Furthermore, in our attempts to increase the yields of nanocrystals ultrasonic energy was applied during the hydrolysis reaction. The primary objective was to develop hydrolysis reaction conditions for the optimum and reproducible CNC production. As such, the use of hydrobromic acid (HBr) with the application of sonication as a function of concentration (1.5–4.0 M), temperature (80–100 °C), and time (1–4 h) was examined. Applying sonic energy during the reaction was found to have significant positive effects as far as reproducible high yields are concerned. Overall, the combination of 2.5 M HBr, 100 °C, and 3 h associated with the sonication during the reaction generated the highest nanocrystal yields. In addition to the optimization study three types of surface modifications including TEMPO-mediated oxidation, alkynation, and azidation were used to prepare surface-activated, reactive CNCs. Subsequently, click chemistry was employed for bringing together the modified nanocrystalline materials in a unique regularly packed arrangement demonstrating a degree of molecular control for creating these structures at the nano level.

Probing the transition state with negative ion photodetachment: the chlorine atom + hydrogen chloride and bromine atom + hydrogen bromide reactions

Abstract: The transition-state region for neutral hydrogen-transfer reactions can be probed by photodetaching the appropriate stable, hydrogen-bonded negative ion. This paper presents a detailed account of this method, in which the Cl + HCl and Br + HBr reactions are investigated by photoelectron spectroscopy of ClHCl{sup {minus}}, BrHBr{sup {minus}}, and the corresponding deuterated species. The photoelectron spectra exhibit resolved vibrational structure attributed to the unstable neutral (ClHCl) or (BrHBr) complex. The BrHBr{sup {minus}} and BrDBr{sup {minus}} spectra exhibit narrow (15-20 meV) peaks that are likely to result from reactive resonance states supported by the Br + HBr potential energy surface, as well as peaks that appear to be from an electronically excited state of the (BrHBr) complex. The BrHBr{sup {minus}} and BrDBr{sup {minus}} results have been analyzed to yield an effective collinear potential energy surface for the Br + HBr reaction.