Green hydrogen is a fuel capable of promoting sustainable energy development and is gaining attention in the current global energy transition framework. The global shift toward decarbonization has triggered a substantial boost in the hydrogen industry. This study presents an overview of the current status of hydrogen production, regulation of the green hydrogen segment, hydrogen storage, distribution, and transportation, and final use and application. We also critically discuss the viability of adopting green hydrogen in terms of possible economic and environmental impacts as well as the main challenges and opportunities it represents for the Chemical Sciences.

O latex de Euphorbia conspicua foi fracionado nas frações triterpênica e irritantes I e II. Da fração triterpênica foram isolados 15 compostos já conhecidos e um novo triterpeno denominado 3β-(E)-cinamoileuforbol. A fração irritante II forneceu o 20-O-acetil-3-O-angeloil-ingenol. A atividade moluscicida dos compostos eufol, 3b-acetoxieufa-8,24-dieno, 3β-(E)-cinamoileuforbol e 20-O-acetil-3-O-angeloil-ingenol foi avaliada. O 20-O-acetil-3-O-angeloil-ingenol apresentou uma LC100 de 1 mg mL-1, a qual foi equivalente ao moluscicida padrão niclosamida. Os compostos eufol, 3b-acetoxieufa-8,24-dieno e 3β-(E)-cinamoileuforbol apresentaram uma fraca atividade moluscicida. O 3β-(E)-cinamoileuforbol foi submetido a testes de mutagenicidade (teste de Ames com TA 98, 100 e 102) na presença e ausência de ativação metabólica (mistura S9). Foram também realizados os ensaios de citotoxicidade (teste MTT) e genotoxicidade (teste dos micronúcleos, CBMN) com e sem mistura S9, em células V79 de Hamster chinês. O 3β-(E)-cinamoileuforbol revelou-se fracamente citotóxico e sem atividade mutagênica ou genotóxica.

Euphorbia conspicua latex was fractionated into triterpenic and irritant fractions I and II. The triterpenic fraction afforded 15 known compounds and a new triterpene, 3β-(E)-cinnamoyleuphorbol. 20-O-Acetyl-3-O-angeloylingenol was isolated from irritant fraction II. The compounds euphol, 3β-acetoxyeupha-8,24-diene, 3β-(E)-cinnamoyleuphorbol and 20-O-Acetyl-3-O-angeloylingenol were evaluated for molluscicidal activity. 20-O-Acetyl-3-O-angeloylingenol presented LC100 value of 1 mg mL-1, equivalent to that of the standard molluscicide niclosamide. Compounds euphol, 3β-acetoxyeupha-8,24-diene and 3β-(E)-cinnamoyleuphorbol showed low molluscicidal activity. Mutagenic assays (Ames test with strains TA 98, 100 and 102) were performed with 3β-(E)-cinnamoyleuphorbol in the presence and absence of metabolic activation (S9 mix). In V79 cells, the cytotoxicity of 3β-(E)-cinnamoyleuphorbol was evaluated using the MTT assay and the genotoxicity was assessed using the cytokinesis-block micronucleus assay (CBMN) with or without S9 mix. Mutagenic or genotoxic activity was not detected, and no significant cytotoxicity was observed for 3β-(E)-cinnamoyleuphorbol at lower doses.

Studies on identification of compounds that make up the aroma and flavor in wines involve research evaluating mainly the influence of terpenes, esters, lactones and alcohols upon these sensory characteristics. However, carbonylic compounds (CC) play an important role concerning the substances that impact aroma to these drinks. Their origin is reported to be linked to the grape's chemical composition, must fermentation or micro-oxidation occurring during storage in barrels. Some CCs, like E-ionone, E-damascenone, siryngaldehyde, can contribute a pleasant aroma and improve the wine quality whereas others are responsible for unpleasant characteristics (acetaldehyde, furfural, 5-hydroxy-methyl furfural, diacetil, E-non-2-enal, etc). A fraction of CCs present is associated with bisulfite ions in the form of hydroxyalkylsulfonic acids. Some of them are stable and play an important role in determining wine quality. The reaction involving the formation of this aduct commonly occurs with CCs of low molar mass, such as formaldehyde and acetaldehyde. The reaction involving CCs with more than three carbon atoms demands further studies.

Embora o primeiro sulfito duplo de valência mista, Cu2SO3.CuSO3.2H2O, tenha sido preparado no início do século XIX por M. Chevreul, o interesse por compostos dessa natureza ressurgiu só depois da metade do século XX com a determinação da estrutura cristalina deste composto e a caracterização de seu espectro de absorção na região do infravermelho. Nos últimos anos, os estudos referentes a este tema têm se intensificado, especialmente após a descoberta da possibilidade de substituição isomórfica do Cu(II) no sal de Chevreul por diversos cátions com o mesmo estado de oxidação, gerando uma série de compostos cujas propriedades são fortemente dependentes da natureza do cátion M(II). Devido às suas propriedades interessantes, esses sistemas de valência mista podem ser usados como modelos para identificar intermediários em processos de corrosão atmosférica, bem como para avaliar o papel de metais de transição como catalisadores de autooxidação de S(IV) na conversão do SO2 na atmosfera.

Although the first mixed valence double sulfite, Cu2SO3.CuSO3.2H2O, was prepared in the early 19th century by M. Chevreul, interest in this type of compound was only rekindled in the mid-1960s, when the crystalline structure of Chevreul's salt was determined and its infrared spectrum characterized. Studies of this type of compound have been intensified in recent years, especially after the discovery that the isomorphic Cu(II) in Chrevreul's salt could be replaced by a divalent metal ion, forming an isomorphic series whose properties are strongly dependent on the nature of the M(II) cation. Because of their interesting properties, these mixed valence systems can be used as models to identify intermediates in atmospheric corrosion processes, and to evaluate the role of transition metals as catalysts of S(IV) autoxidation in the conversion of SO2 in the atmosphere.

A série isomórfica de sulfitos duplos com fórmula empírica Cu2SO3.MSO3.2H 2O (onde M é Cu, Fe, Mn ou Cd) é preparada pela substituição do Cu(II) no sal de Chevreul, Cu2SO3.CuSO3.2H 2O, por íons de metais de transição, tais como Fe(II), Mn(II) e Cd(II). Como conseqüência, as espécies isomórficas apresentam colorações distintas. Cálculos de modelagem molecular foram empregados neste trabalho para o centro dimérico [CuI2(SO3) 2(SO3)2]6- . O espectro eletrônico do sal de Chevreul consiste de uma banda de transferência de carga em 425 nm associada ao cromóforo [CuI2(SO3) 2(SO3)2]6- e duas transições de campo ligante a 785 e 1000 nm envolvendo distorção de Jahn-Teller dos níveis do Cu(II). Além disso, uma banda adicional de transferência de intervalência é observada em 500 nm, sendo responsável pela sua coloração vermelha característica. A substituição do íon Cu(II) pelos íons Fe(II), Mn(II) e Cd(II) não elimina a banda de absorção em 425 nm, associada à transição de transferência de carga centrada nos sítios Cu(I), porém a banda original em 500 nm desaparece, em concordância com a atribuição de transição intervalência.

The isomorphic series of double sulfites with empirical formula Cu2SO3.MSO3.2H 2O (where M is Cu, Fe, Mn, or Cd) have been prepared from the Cu(II) replacement by transition metal ions such as Mn(II), Fe(II) and Cd(II) ions in Chevreul's salt, Cu2SO3.CuSO3.2H 2O. As a consequence, the isomorphic species present distinct colors. Molecular modeling calculations were carried out for the dimeric [CuI2(SO3) 2(SO3)2]6- center. The electronic spectra of the Chevreul's salt consist of a charge-transfer band around 425 nm associated with the [CuI2(SO3) 2(SO3)2]6- chromophore and two ligand field transitions at 785 and 1000 nm involving the Jahn-Teller splitting of the Cu(II) levels. An additional intervalence-transfer band, responsible for its characteristic red color, can be found at 500 nm. The replacement of the Cu(II) ions for Fe(II), Mn(II) and Cd(II) does not eliminate the absorption band at 425 nm, supporting its assignment as a charge-transfer transition centered on the Cu(I) sites; while the original band at 500 nm disappears, in agreement with its intervalence transfer nature.