scholarly journals Atmospheric Sulfuric Acid‐Dimethylamine Nucleation Enhanced by Trifluoroacetic Acid

2020 ◽  
Vol 47 (2) ◽  
Author(s):  
Yiqun Lu ◽  
Ling Liu ◽  
An Ning ◽  
Gan Yang ◽  
Yiliang Liu ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Trifluoroacetic Acid

Non-peripherally alkylamino-substituted phthalocyanines: Synthesis, spectral, photophysical and acid-base properties

2019 ◽  
Vol 23 (04n05) ◽  
pp. 427-436 ◽  
Author(s):  
Lucia Kociscakova ◽  
Merve Ipek Senipek ◽  
Petr Zimcik ◽  
Veronika Novakova
Keyword(s):  
Sulfuric Acid ◽  
Trifluoroacetic Acid ◽  
Fluorescence Emission ◽  
Optimal Conditions ◽  
Oxygen Production ◽  
Acid Base ◽  
Metal Free ◽  
Near Ir ◽  
Zinc Phthalocyanines ◽  
Photophysical Study

Non-peripherally substituted metal-free and zinc phthalocyanines (Pcs) bearing four diethylamino groups and four Br atoms were prepared. Optimal conditions for synthesis of corresponding precursor ([Formula: see text] 3-bromo-6-(diethylamino)phthalonitrile) either by nucleophilic substitution or by Buchwald–Hartwig coupling were studied. Noteworthy, 3,6-bis(diethylamino)phthalonitrile was also formed, nevertheless only at low yield (typically below 1%) and all attempts for its cyclotetramerization failed. Q bands of prepared Pcs were strongly red shifted up to the near-IR region (769 and 800 nm in THF for zinc and metal-free Pc, respectively). Unusually large hypsochromic shifts of the Q bands, 130 and 80 nm for metal-free and zinc Pc, respectively, were observed upon treating these Pcs with trifluoroacetic acid, which was attributed to the protonation of non-peripheral amines. Treatment with sulfuric acid led to subsequent protonation on the azomethine nitrogens as well. Photophysical study revealed low fluorescence emission of both derivatives ([Formula: see text] <0.03, in THF) and efficient singlet oxygen production only for zinc Pc ([Formula: see text] 0.77 in THF and 0.60 in DMF).

REACTIONS OF AMIDES AND RELATED COMPOUNDS: III. N.M.R. INVESTIGATION OF THE PROTONATION OF N,N-DIMETHYLNITROSOAMINE, N,N-DIETHYLNITROSOAMINE, AND N-NITROSOPIPERIDINE

1966 ◽  
Vol 44 (2) ◽  
pp. 105-109 ◽  
Author(s):  
Stephen J. Kuhn ◽  
John S. McIntyre
Keyword(s):  
Sulfuric Acid ◽  
Magnetic Resonance ◽  
Perchloric Acid ◽  
Trifluoroacetic Acid ◽  
Proton Magnetic Resonance ◽  
Acid Solutions ◽  
Concentrated Sulfuric Acid ◽  
Related Compounds ◽  
Equimolar Solution ◽  
Magnetic Resonance Spectra

Protonation of N,N-dimethylnitrosoamine has been investigated by dissolving the nitrosoamine in different acids and recording the proton magnetic resonance spectra of these solutions. Concentrated sulfuric acid, sulfuric acid monohydrate, perchloric acid (72%), trifluoroacetic acid, and fluorosulfuric acid have been used in this study. Only in fluorosulfuric acid near 0 °C and lower was a new signal observed for the protonated nitrosoamine molecule. Integration of the peaks has shown that only one proton is captured by the nitrosoamine. The following structure is suggested for the protonated nitrosoamine.[Formula: see text]The n.m.r. spectra of fluorosulfuric acid solutions of N,N-diethylnitrosoamine and N-nitrosopiperidine also show separate signals for the captured proton.The n.m.r. spectrum of an equimolar solution of N,N-dimethylnitrosoamine, N,N-dimethylformamide, and trifluoroacetic acid in 2-nitropropane indicates that N,N-dimethylnitrosoamine is a weaker base.

scholarly journals Influence of atmospheric conditions on the role of trifluoroacetic acid in atmospheric sulfuric acid–dimethylamine nucleation

2021 ◽  
Vol 21 (8) ◽  
pp. 6221-6230
Author(s):  
Ling Liu ◽  
Fangqun Yu ◽  
Kaipeng Tu ◽  
Zhi Yang ◽  
Xiuhui Zhang
Keyword(s):  
Sulfuric Acid ◽  
Trifluoroacetic Acid ◽  
Density Functional ◽  
Cluster Formation ◽  
Formation Rate ◽  
Urban Environments ◽  
Nucleation Process ◽  
Atmospheric Conditions ◽  
Wide Range

Abstract. Ambient measurements combined with theoretical simulations have shown evidence that the tropospheric degradation end-products of Freon alternatives, trifluoroacetic acid (TFA), one of the most important and abundant atmospheric organic substances, can enhance the nucleation process based on sulfuric acid (SA) and dimethylamine (DMA) in urban environments. However, TFA is widespread all over the world under different atmospheric conditions, such as temperature and nucleation precursor concentration, which are the most important factors potentially influencing the atmospheric nucleation process and thus inducing different nucleation mechanisms. Herein, using the density functional theory combined with the Atmospheric Cluster Dynamics Code, the influence of temperature and nucleation precursor concentrations on the role of TFA in the SA–DMA nucleation has been investigated. The results indicate that the growth trends of clusters involving TFA can increase with the decrease in temperature. The enhancement on particle formation rate by TFA and the contributions of the SA–DMA–TFA cluster to the cluster formation pathways can be up to 227-fold and 95 %, respectively, at relatively low temperature, low SA concentration, high TFA concentration, and high DMA concentration, such as in winter, at the relatively high atmospheric boundary layer, or in megacities far away from industrial sources of sulfur-containing pollutants. These results provide the perspective of the realistic role of TFA in different atmospheric environments, revealing the potential influence of the tropospheric degradation of Freon alternatives under a wide range of atmospheric conditions.

Intensification of the Sulfuric Acid Alkylation Process with Trifluoroacetic Acid

AIChE Journal ◽  
2018 ◽  
Vol 65 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Liantang Li ◽  
Jisong Zhang ◽  
Chencan Du ◽  
Guangsheng Luo
Keyword(s):  
Sulfuric Acid ◽  
Trifluoroacetic Acid ◽  
Acid Alkylation ◽  
Sulfuric Acid Alkylation ◽  
Alkylation Process

scholarly journals Influence of atmospheric conditions on the role of trifluoroacetic acid in atmospheric sulfuric acid-dimethylamine nucleation

2020 ◽  
Author(s):  
Ling Liu ◽  
Fangqun Yu ◽  
Kaipeng Tu ◽  
Zhi Yang ◽  
Xiuhui Zhang
Keyword(s):  
Sulfuric Acid ◽  
Trifluoroacetic Acid ◽  
Density Functional ◽  
Cluster Formation ◽  
Formation Rate ◽  
Precursor Concentration ◽  
Nucleation Process ◽  
Atmospheric Conditions ◽  
Wide Range

Abstract. Ambient measurements combined with theoretical simulations have shown evidence that the tropospheric degradation end-products of Freon alternatives, trifluoroacetic acid (TFA), one of the most important and abundant atmospheric organic substances, can enhance the process of sulfuric acid (SA) – dimethylamine (DMA) – based nucleation process in urban environments. However, TFA is widespread all over the world with different atmospheric conditions, such as temperature and nucleation precursor concentration, which are the most important factors potentially influencing the atmospheric nucleation process and thus inducing different nucleation mechanisms. Herein, using the Density Functional Theory combined with the Atmospheric Cluster Dynamics Code, the influence of temperature and nucleation precursor concentration on the role of TFA in the SA-DMA nucleation has been investigated. The results indicate that the growth trends of clusters involving TFA can increase with the decrease of temperature. The enhancement of particle formation rate by TFA and the contributions of SA-DMA-TFA cluster to the cluster formation pathways can be up to as much as 227 times and 95 %, respectively, at relatively low temperature, low SA concentration, high TFA concentration and high DMA concentration, such as in winter or at relatively high atmospheric boundary layer and in megacities far away from industrial sources of sulfur-containing pollutants. These results provide the perspective of the realistic role of TFA in different atmospheric environments, revealing the potential influence of the tropospheric degradation of Freon alternatives under a wide range of atmospheric conditions.

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