concentrated sulfuric acid
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2022 ◽  
Vol 52 (5) ◽  
Author(s):  
Wellington Ferreira do Nascimento ◽  
Fabiana Gonçalves Bastos ◽  
Gabriel Dequigiovanni ◽  
Eliane Gomes Fabri ◽  
Maria Imaculada Zucchi ◽  
...  

ABSTRACT: Annatto (Bixa orellana L.) is an arboreal species domesticated in Amazonia from its wild ancestor (B. orellana var. urucurana). Bixin extracted from its orthodox seeds is a natural dye widely used in the food industry. This study evaluated methods to overcome seed dormancy and determine the germination potential, comparing domesticated and wild annatto populations. Seeds from two domesticated-type populations and two families of a wild-type population, stored for two years after field collection, were submitted to five treatments to overcome dormancy: T1 - control; T2 - mechanical scarification (with sandpaper); T3 - mechanical scarification (with sandpaper) + immersion in water at 36 ºC overnight (12 hours); T4 - immersion in water at room temperature (23 ºC, on average) for 24 h; T5 - immersion in concentrated sulfuric acid (95 - 98%) for 15 min + running water for 3 min. Highly significant differences (P < 0.001) were observed in the germination percentage of annatto seeds between wild and domesticated types, and among the treatments tested. Domesticated types showed higher germination percentage (10 - 58%) over all treatments when compared to the wild type (0 - 44%). The best treatments were those performed with mechanical scarification. Given the simplicity, we concluded that mechanical scarification with sandpaper is a good alternative to overcome dormancy of annatto seeds.


ACS Omega ◽  
2021 ◽  
Author(s):  
Yuntao Tian ◽  
Yuanfang Wan ◽  
Liangliang Zhang ◽  
Guangwen Chu ◽  
Adrian C. Fisher ◽  
...  

Author(s):  
И.А. Щурова ◽  
Н.А. Алексеева ◽  
С.В. Сысолятин ◽  
В.В. Малыхин

Статья посвящена усовершенствованию способа получения 2,4,6-тригидрокситолуола, востребованного химического реагента в синтезе азокрасителей и пигментов, а также химико-фармацевтических препаратов и различных полимеров. Основным сырьем для его получения является 2,4,6-тринитротолуол, который подвергают каталитическому гидрированию с последующим гидролизом образовавшегося 2,4,6-триаминотолуола. В данной работе предложены условия многоциклового использования палладиевого катализатора гидрирования 2,4,6-тринитротолуола, позволяющие сохранять активность катализатора и повысить выход 2,4,6-триаминотолуола выше 98 %. Аминопроизводное выделяется в виде дисульфата действием концентрированной серной кислоты. Кроме того, изучено влияние соотношения вода/дисульфат 2,4,6-триаминотолуола на выход 2,4,6-тригидрокситолуола; найдены условия, в которых выход на стадии гидролиза увеличен до 83-84 %. Проведен сравнительный анализ различных способов выделения 2,4,6-тригидрокситолуола из реакционной массы. The paper is concerned with upgrading the synthetic method for 2,4,6-trihydroxytoluene, an in-demand chemical reactant in the synthesis of azo-dyes and pigments, as well as chemical pharmaceuticals and various polymers. The basic feedstock for the synthesis thereof is 2,4,6-trinitrotoluene, which is subjected to catalytic hydrogenation followed by hydrolysis of the resulting 2,4,6-triaminotoluene. Here we suggest conditions for the multicycle use of Pd catalyst employed for the hydrogenation of 2,4,6-trinitrotoluene, which allow the catalyst activity to be retained and the yield of 2,4,6-triaminotoluene to be enhanced above 98%. The amino derivative is liberated as the disulfate by concentrated sulfuric acid. Moreover, we examined how the ratio of water / 2,4,6-triaminotoluene disulfate influences the yield of 2,4,6-trihydroxytoluene. Conditions were found in which the yield from hydrolysis is 83-84 %. Different methods for the isolation of 2,4,6-trihydroxytoluene from the reaction mixture were comparatively analyzed.


2021 ◽  
Vol 118 (52) ◽  
pp. e2110889118
Author(s):  
William Bains ◽  
Janusz J. Petkowski ◽  
Paul B. Rimmer ◽  
Sara Seager

The atmosphere of Venus remains mysterious, with many outstanding chemical connundra. These include the unexpected presence of ∼10 ppm O2 in the cloud layers, an unknown composition of large particles in the lower cloud layers, and hard to explain measured vertical abundance profiles of SO2 and H2O. We propose a hypothesis for the chemistry in the clouds that largely addresses all of the above anomalies. We include ammonia (NH3), a key component that has been tentatively detected both by the Venera 8 and Pioneer Venus probes. NH3 dissolves in some of the sulfuric acid cloud droplets, effectively neutralizing the acid and trapping dissolved SO2 as ammonium sulfite salts. This trapping of SO2 in the clouds, together with the release of SO2 below the clouds as the droplets settle out to higher temperatures, explains the vertical SO2 abundance anomaly. A consequence of the presence of NH3 is that some Venus cloud droplets must be semisolid ammonium salt slurries, with a pH of ∼1, which matches Earth acidophile environments, rather than concentrated sulfuric acid. The source of NH3 is unknown but could involve biological production; if so, then the most energy-efficient NH3-producing reaction also creates O2, explaining the detection of O2 in the cloud layers. Our model therefore predicts that the clouds are more habitable than previously thought, and may be inhabited. Unlike prior atmospheric models, ours does not require forced chemical constraints to match the data. Our hypothesis, guided by existing observations, can be tested by new Venus in situ measurements.


Pharmacia ◽  
2021 ◽  
Vol 68 (4) ◽  
pp. 933-939
Author(s):  
Oksana Strus ◽  
Mariana Fedorovska ◽  
Serhii Holota ◽  
Natalia Polovko

Methodological bases and uniform standardization criteria of humic compounds as substances for drug products have not been developed yet. This is due to the structural complexity of humic compounds, the variety of ways to extract them from natural objects, the impossibility of using many classical methods of analytical chemistry to identify and quantify humic substances (HS), the lack of standard samples. The identification of humic acids (HA) in the aqueous sapropel extract (ASE) is identified after extracting from ASE by alkaline hydrolysis by the quantification method. After further precipitation with a concentrated sulfuric acid solution characteristic dark brown color is appeared. It was carried out the HA extraction from the sample of ASE, the precipitation of HA, the oxidation of HA and Mohr’s salt titration in accordance with the methodology developed on the basis of SSTU 7083:2009. It was determined that the total mass fraction of HA in the ASE sample was 83.8 mg/g± 0.12%. The methods of identification and quantification of the total mass of HA in ASE have been developed and validated. The ASE has been standardized.


Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1506
Author(s):  
Damir Tazeev ◽  
Lenar Musin ◽  
Nikolay Mironov ◽  
Dmitry Milordov ◽  
Elvira Tazeeva ◽  
...  

In the present work, the first data on the catalytic activity of d-metal complexes of petroleum porphyrins obtained via two-stage re-metallization (acid demetallization with subsequent metalation) of high-purity petroleum vanadyl porphyrins are presented. During acid demetallization of petroleum vanadyl porphyrins, the highest yield (49%) and spectral purity of free petroporphyrin bases were achieved with concentrated sulfuric acid and a diluted solution of vanadyl porphyrins in chloroform. In the series of divalent cations of Mn, Fe, Co, Ni, Cu, and Zn, only the last four metals are complexed with demetallated petroporphyrins without significant changes in their component composition, whereas the interaction with Mn and Fe cations causes an evident structural transformation or even full degradation of petroporphyrin macrocycles, respectively. The composition and spectral purity of petroleum porphyrin-containing reactants and products were analyzed by FT-IR, UV-Vis, NMR, and MALDI-TOF mass spectroscopic methods. The obtained petroporphyrin-based d-metal complexes were assayed by the reaction of 2-mercaptoethanol oxidative dimerization, in which the copper porphyrins exhibited the highest catalytic activity.


Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2277
Author(s):  
Gerald S. Pullman ◽  
Kylie Bucalo ◽  
Ron O. Determann ◽  
Jennifer M. Cruse-Sanders

Rhus michauxii is a perennial rhizomatous shrub native to the southeastern United States that is found mainly in sunny, dry, open rocky or sandy woodlands. Moreover, it is found on ridges or river bluffs in the inner coastal plane and lower piedmont of Virginia, Georgia, and the Carolinas. Habitat conversion to agriculture, suppression of fires, and low reproduction have caused R. michauxii to become rare and it is now federally listed as threatened. Methods are needed to multiply and conserve R. michauxii. Protocols were developed for seed cryopreservation, in vitro germination, and micropropagation for R. glabra and R. michauxii. Seed scarification in concentrated sulfuric acid for 6 h and germination on ½ MS medium resulted in germination up to 96% for control and cryopreserved seeds of R. glabra and 70 and 40% for control and cryopreserved seeds of R. michauxii. Shortly after germination in vitro, young seedlings were established in a greenhouse potting mix providing new plants from the endemic Georgia R. michauxii populations. Several of the findings meet goals within the R. michauxii recovery plan by providing methods for sexual and asexual multiplication and long-term seed storage under cryogenic conditions. The protocols developed will assist in the safeguarding and conservation of dwindling natural R. michauxii populations.


2021 ◽  
Author(s):  
Bo Deng ◽  
Ya-xiong Wang ◽  
Li Huo ◽  
Ying Wang ◽  
Li’e Jin

Abstract In this paper, tannic acid, a polyphenolic substance rich in plants, is modified by the glutamic acid and cross-linked with formaldehyde to prepare a high acid density tannin-glutamate acid resin-based imitation enzyme solid acid catalyst (T-Glu-R), which is completely different from traditionally carbon-based solid acid synthesized by concentrated sulfuric acid and carbonized matter. The solid acid catalyst was characterized by Fourier transform infrared spectroscopy, scanning electron microscope, thermogravimetry, and X-ray photoelectron spectroscopy. The catalytic activity and cycle performance of T-Glu-R in the cellulose hydrolysis reaction were evaluated. The results show that the acid density of T-Glu-R reached 7.28 mmol/g, which is much higher than that of the highest acid density of carbon-based solid acid. Microcrystalline cellulose was hydrolyzed in distilled water at 180 °C for 2 h, the yield of total reducing sugars reached 72.15%. After four cycles of hydrolysis, the yield was only reduced by 4.32%, showing excellent cycle performance and stability. The study provides a new strategy with the synthesis of solid acid catalyst for hydrolysis of cellulose converted into platform compounds without concentrated sulfuric acid.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anna Malaika ◽  
Karolina Ptaszyńska ◽  
Mieczysław Kozłowski

AbstractEthylene was thermocatalytically transformed into carbon products via a CCVD process. The filamentous carbon obtained was further modified with concentrated sulfuric acid or 4‐benzenediazonium sulfonate (BDS) to produce acid-type catalysts. The as-prepared samples were characterized by SEM and TEM techniques to confirm their morphological features. TG, XRD, elemental, and porosity analyses were also performed to assess the quality of these materials. The fabricated carbons were tested in eco-friendly green synthesis of value-added fuel bio-additives, namely in glycerol esterification. The reaction of glycerol transformation was performed with acetic acid at 80 °C using different glycerol to acetic acid (Gly/AA) molar ratios. The samples functionalized with diazonium salt showed better performance in the above process than those modified with H2SO4, and this was found to be directly related to the degree of surface functionalization with acidic sites. BDS-modified carbon fibers allowed obtaining acceptable results within 6 h when the reaction was performed with a Gly/AA molar ratio of 1:6, however, the dominant products in this case were mono- and diacetins. Extended reaction time altered the distribution of products. Finally, the combined selectivity to the targeted acetins (i.e., DA and TA) was about 75.5%. A direct correlation between the content of –SO3H groups of CNFs and the yield of higher acetins was found.


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