Liquid Methylamine Research Articles

Fully Screen‐Printed Perovskite Solar Cells with 17% Efficiency via Tailoring Confined Perovskite Crystallization within Mesoporous Layer

AbstractUsing a screen‐printing techniques is thought to be a good candidate for simplified, cost‐effective, reliable, and scalable fabrication of fully printed perovskite solar cells (PSCs) for industrialization. Nevertheless, the screen‐printing of perovskite film has not been realized until recently. This group finished the work using ionic liquid methylamine acetate (MAAc) as pure solvent. However, the space‐confining effect during the perovskite crystallization in mesoporous impeded the escape of bottom MAAc molecules, which leads to the poor crystalline quality of the screen‐printed film. In this work, ionic liquid methylamine propionate (MAPa) with stronger coordination is introduced as a co‐solvent to promote the escape of MAAc molecules by forming the solvent volatilization channels in a confined mesoporous structure, which results in the complete MAAc volatilization and high filling degree of perovskite crystals inside the mesoporous structure. Also, MAPa promotes the vertical growth of perovskite crystals and coordinates with unbonded Pb2+ on the perovskite surface, leading to efficient charge transport and interfacial band alignment of the screen‐printed film. Finally, fully screen‐printed PSCs yields a champion power conversion efficiency (PCE) of ≈17%, which is the record value for fully screen‐printed PSCs. Moreover, the unencapsulated device shows robust operational stability that maintains >85.3% of initial PCE (25%RH and 25 °C) under continuous illumination at the maximum power point after 250 h.

Perovskite synthesis out in the open

Solar Cells Although methods have been developed that create the photoactive black perovskite phase of formamidinium lead iodide (α-FAPbI3), these routes are temperature and humidity sensitive and less compatible with large-scale solar cell production. Hui et al. report an alternative route in which vertically aligned lead iodide thin films are grown from the ionic liquid methylamine formate. Nanoscale channels in the films lower the barrier to permeation of formamidinium iodide and enable transformation to α-FAPbI3, even at high humidity and room temperature. Solar cells made with these films have power conversion efficiencies as high as 24.1% that display high stability. Science , this issue p. [1359][1] [1]: /lookup/doi/10.1126/science.abf7652

Stabilizing black-phase formamidinium perovskite formation at room temperature and high humidity.

The stabilization of black-phase formamidinium lead iodide (α-FAPbI3) perovskite under various environmental conditions is considered necessary for solar cells. However, challenges remain regarding the temperature sensitivity of α-FAPbI3 and the requirements for strict humidity control in its processing. Here we report the synthesis of stable α-FAPbI3, regardless of humidity and temperature, based on a vertically aligned lead iodide thin film grown from an ionic liquid, methylamine formate. The vertically grown structure has numerous nanometer-scale ion channels that facilitate the permeation of formamidinium iodide into the lead iodide thin films for fast and robust transformation to α-FAPbI3 A solar cell with a power-conversion efficiency of 24.1% was achieved. The unencapsulated cells retain 80 and 90% of their initial efficiencies for 500 hours at 85°C and continuous light stress, respectively.

Improvement of Complete Circulation of Aqueous Solution for Urea Production Processing with Premixing

Half of the urea is produced by complete circulation of aqueous solution processing in China. The mixing between the gas and liquid is the key of the technology. This paper presents an improvement of the complete circulation of aqueous solution processing by premixing and atomizing liquid NH3 and Methylamine. And a novel atomizer was developed for the high pressure and limited space. We proposed a new model based on the two innovations and predicted the performance of the suggested processing. The modeling prediction agreed well with the experimental results. For the same urea synthesis tower structure, the conversion rate increased 3~5%. This indicates this technology is competitive to retrofit the existed units.

Homoleptic Octahedral Methylamine Complexes of Manganese(II): Solvothermal Syntheses and Crystal Structures of [Mn(NH2CH3)6]Cl2 and the Pentaselenide [Mn(NH2CH3)6]Se5

Abstract[Mn(NH2CH3)6]Cl2 (1) and [Mn(NH2CH3)6]Se5 (2) were prepared by solvothermal reactions in liquid methylamine from MnCl2 at 150 °C for 1 and from a mixture of MnCl2, Rb2Se and selenium at 120 °C for 2. Both 1 and 2 were obtained in high yields as colorless and dark‐red crystals and represent the first homoleptic methylamine complexes with coordination number six. Compound 1 crystallizes rhombohedral (R$\bar{3}$, Z = 3) and is built of only slightly distorted octahedral [Mn(NH2CH3)6]2+ cations and Cl– anions. Compound 2 crystallizes orthorhombic (Pnna, Z = 4) and is built of octahedral [Mn(NH2CH3)6]2+ cations showing a strong angular distortion and of Se52– anions in the form of chains in transoid conformation. DFT calculations reveal an almost undistorted ground state structure for [Mn(NH2CH3)6]2+ with N–Mn–N angular distortions of 1° from orthogonality, close to the structure found for the complex in 1. The calculated energy necessary for a distortion as found in the structure of 2 is rather low and amounts to 26 kJmol–1 which is in the range typical for hydrogen bonds. The N–Mn–N angular distortions of the complex cation in 2, observed in the range of 10°, is caused by cation‐anion interactions in the crystal structure by N–H····Se hydrogen bonds.

Urinary creatine and methylamine excretion following 4 × 5 g · day−1 or 20 × 1 g · day−1 of creatine monohydrate for 5 days

In this study, we examined the effect of two creatine monohydrate supplementation regimes on 24-h urinary creatine and methylamine excretion. Nine male participants completed two trials, separated by 6 weeks. Participants ingested 4 × 5 g · day−1 creatine monohydrate for 5 days in one trial and 20 × 1 g · day−1 for 5 days in the other. We collected 24-h urine samples on 2 baseline days (days 1–2), during 5 days of supplementation (days 3–7), and for 2 days post-supplementation (days 8–9). Urine was assayed for creatine using high-performance liquid chromatography and methylamine using gas chromatography. Less creatine was excreted following the 20 × 1 g · day−1 regime (49.25 ± 10.53 g) than the 4 × 5 g · day−1 regime (62.32 ± 9.36 g) (mean ± s; P < 0.05). Mean total excretion of methylamine (n = 6) over days 3–7 was 8.61 ± 7.58 mg and 24.81 ± 25.76 mg on the 20 × 1 g · day−1 and 4 × 5 g · day−1 regimes, respectively (P < 0.05). The lower excretion of creatine using 20 × 1 g · day−1 doses suggests a greater retention in the body and most probably in the muscle. Lower and more frequent doses of creatine monohydrate appear to further attenuate formation of methylamine.

Electrochemical and Theoretical Investigation of Corannulene Reduction Processes

The voltammetric generation of corannulene anions was investigated over a large range of experimental conditions comprising either "traditional" electrochemical solvents, such as dimethylformamide, acetonitrile, and tetrahydrofuran, or "unconventional" solvents, such as liquid ammonia, liquid methylamine, or liquid dimethylamine, and several different supporting electrolytes. Strong ion pairing effects were found to dominate the electrochemical generation of corannulene higher anions, and through the suitable choice of the solvent/electrolyte system, we observed, for the first time, the reversible electrochemical generation of up to the triply reduced corannulene. The standard potentials obtained experimentally compared rather well with the theoretical values calculated by ab initio and density functional methods, in which solvation and ion pairing effect were explicitly taken into account. In particular, the calculations considered the effect of the electrolyte cation size on ion pairing in order to rationalize the occurrence of the third reduction within the experimental potential window.

Methylamination of some 3-nitro-1,5-naphthyridines with liquid methylamine/potassium permanganate

3-Nitro-1,5-naphthyridine and its 2-substituted derivatives (1a-f) are dehydro-methylaminated with a solution of potassium permanganate in liquid methylamine (LMA-PP) to the corresponding 4-methylamino-3-nitro-1,5-naphthyridines (3a-e). The intermediary 4-methylamino σ adducts of 2-R-3-nitro-1,5-naphthyridines (R  H, NH2, Cl, NHCH3, OC2H5, OH) (2a-f) are detected by 1H nmr spectroscopy. The observed highly regioselective course of study reactions was confirmed by PM3 quantum chemical calculations of the reaction pathway. The calculations show satisfactory agreement between calculated and observed results. A convenient synthesis of 2-hydroxy- and 4-methylamino-3-nitro-1,5-naphthyridine are reported.

The structure of liquid methylamine and solutions of lithium in methylamine

The technique of hydrogen/deuterium isotopic substitution in neutron diffraction has been used to measure the intra- and intermolecular correlations in liquid methylamine, and 2 and 8 MPM (mole percent metal) lithium methylamine solutions. We find that pure methylamine forms only one strong hydrogen bond per molecule, with evidence for weaker orientations towards the methyl group. As one introduces lithium metal, the intramolecular structure of the solvent is unaltered. However, intermolecular hydrogen bonding is progressively disrupted as the concentration of (solvated) cations and excess electrons increases. Comparison of the total structure factors for 0, 2, 8 and 20 MPM lithium methylamine solutions shows that the greatest shift in the position of the principal peak occurs between 8 and 20 MPM. This can be correlated to the electron delocalization associated with the non-metal-metal transition.

The local structure in liquid methylamine and methylamine–water mixtures

Molecular dynamics (MD) computer simulations are carried out on liquid methylamine and on 10 and 30 wt % aqueous solutions of methylamine. The local three-dimensional structure in these liquid systems is investigated using standard one-dimensional radial distribution functions and the fully three-dimensional measure of the local structure around the molecule, spatial distribution functions. Time correlation functions for the linear and angular motion of methylamine in the molecular coordinate system are also explored. From this analysis, a detailed structural picture emerges, revealing local molecular environments in these liquids that are both complex and varied. Hydrogen bond balance is found to play a key role in determining preferred arrangements. Strong hydrogen bonds are formed around the amino group in the pure liquid and in aqueous solution. At the same time, there is a strong hydrophobic association of methyl groups. The hydration structure in aqueous solution is found to be particularly rich, where in addition to the usual H-bonding nearest neighbors in the first hydration shell of the amino group, there are bridging water molecules and a novel type of distinctly non-H-bonding neighbors. The hydration structure in aqueous methylamine solution differs substantially from that found in methanol–water liquid mixtures.

Methylamination of some 3,6-dinitro-1,8-naphthyridines with liquid methylamine – potassium permanganate

3,6-Dinitro-1,8-naphthyridine and its 2-substituted derivatives are dehydro-methylaminated with the solution of potassium permanganate in liquid methylamine (LMA–PP) to the corresponding mono- or mono- and bis(methylamino)-3,6-dinitro-1,8-naphthyridines. In the case of 2-chloro- and 2-methoxy-3,6-dinitro-1,8-naphthyridine the replacement of chloro and methoxy substituents by the NHCH3 group occurs as well. Quantum-chemical calculations indicate the reactions to be controlled by the interaction of the frontal molecular orbitals (FMO) of the reagents. Moreover the heats of formation of intermediary methylamino-σ-adducts and transition states are calculated for the reaction studied. The calculations show satisfactory agreement between calculated and observed results. A convenient synthesis of some 2-substituted-3,6-dinitro-1,8-naphthyridines is reported.Key words: methylaminations, calculations PM3, nitro-1,8-naphthyridines, oxidation.

Methylamination of some 3,6-dinitro-1,8-naphthyridines with liquid methylamine – potassium permanganate

Methylamination of some 3,6-dinitro-1,8-naphthyridines with liquid methylamine – potassium permanganate

Oxidative methylamination of some nitropyridines

2-, 3-, 4-Nitropyridine (1a, i, j) and some simple derivatives of 3-nitropyridine (1b-h) undergo dehydro-methylamination in a solution of potassium permanganate in liquid methylamine. In the case of 2- and 6-chloro and 6-methoxy derivatives of 3-nitropyridine (1b-d) dechloro- or demethoxy-methylamination occurs as well.

Isotope effects in tritium exchange between liquid pyrrole, pyrrolidine and gaseous hydrogen

The overall tritium separation factor between molecular hydrogen and liquid pyrrole and pyrrolidine has been measured between 280 and 325 K. The data are comparable with values of α measured for similar exchange reactions involving ammonia and methylamine. There is a visible correlation of the isotope effect with the energy of hydrogen bond formed by NH groups of liquid ammonia, methylamine, pyrrole and pyrrolidine.

Methylamination of Some 3‐Nitro‐1,8‐naphthyridines with Liquid Methylamine/Potassium Permanganate

Abstract3‐Nitro‐1,8‐naphthyridines (1a–1h) are aminated, with a liquid methylamine solution of potassium permanganate (LMA/PP), to the corresponding 4‐methylamino‐substituted nitro compounds (3a–g). The intermediary 4‐methylamino‐σ‐adducts of some 3‐nitro‐1,8‐naphthyridines are detected by 1H‐NMR spectroscopy. Quantum chemical calculations show the reactions to be controlled by the interaction of the frontal molecular orbitals (FMO) of the reagents. Moreover, the heats of formation of the intermediary methylamino‐σ‐adducts of 1a and 1c–1h and transition states are calculated for the reactions studied. The agreement, between the calculated and observed results, is satisfactory for the reactions described.

Superconducting Properties of Alkali Doped C60 Prepared by Precipitation from Liquid Methylamine or Ammonia

Abstract An extremely convenient method of preparing alkali doped face-centered cubic phases of C60 consists of the partial solubilization of the constituent materials in liquid ammonia or monomethylamine followed by precipitation and annealing. The preparation and properties of Rb3C60, K3C60 and Rb2CsC60 prepared in this manner from monomethylamine are decribed. When attempting to prepare Rb2NaC60 from liquid ammonia, one obtains a phase separated material, consisting of the energetically more stable superconducting Rb3C60 and nonsuperconducting NaxC60. This sample exhibits a very sharp superconducting transition temperature at 26.3 K. The decrease in Tc with respect to that of pure-phase Rb3C60 is explained as the result of the decrease in density of states in Josephson-like junctions formed between the two phases. This composition displays a large volume fraction of superconductivity, and all measurements of superconducting parameters are extremely well defined, implying high phase purity of the Rb3C60...

Amination of dinitrobenzenes with liquid methylamine/potassium‐permanganate

Abstract1,3‐Dinitrobenzene (1a) and some simple monosubstituted derivatives (1b–g) were aminated with a liquid methylamine solution of potassium permanganate (LMA/PP) to give the corresponding mono‐ and bis(methylamino)‐substituted compounds (3a‐e and 4a). 1,2‐Dinitrobenzene (1i) was aminated with LMA/PP to give 2‐(methylamino)‐1‐nitrobenzene (3f) in high yield. The intermediacy of 4‐(methylamino) σ‐adducts of 1,3‐dinitrobenzene (2a), 2‐chloro‐ (2b) and 2‐amino‐1,3‐dinitrobenzene (2c) was established by 1H‐NMR spectroscopy. Quantum‐chemical calculations for the dinitrobenzenes suggest that, in general, the experimentally observed regioselectivity of the methylamination is satisfactorily described by frontier molecular orbital (FMO) interaction of the reagents.

Amination of Some Nitroisoquinolines with Liquid Methylamine/Potassium Permanganate

Abstract5‐Nitro‐, 3‐methyl‐5‐nitro‐, 5, 7‐dinitro‐, 5‐chloro‐8‐nitro‐ and 8‐chloro‐5‐nitroisoquinoline (1a–e) as well as 5‐nitroisoquinoline N‐oxide (1f) are aminated with a liquid methylamine solution of potassium permanganate (LMA/PP) to the corresponding mono‐ or mono‐ and bis(methylamino)‐substituted nitro compounds 2 (a–m). 1‐Nitroisoquinoline (1g) is aminated with LMA/PP to 1‐(methylamino)isoquinoline (2n). Quantum‐chemical calculations for some mononitroisoquinolines suggest that, in general, the experimentally observed regioselectivity of the amination is controlled by an interaction of frontal molecular orbitals (FMO) of the reagents. magnified image

Oxidative Methylamination of Nitroquinolines

Abstract3‐, 5‐, 6‐, 7‐ and 8‐nitroquinoline as well as 5,7‐ and 6,8‐dinitroquinoline are methylaminated with a liquid methylamine solution of potassium permanganate (LMA/PP) to the corresponding mono‐ and bis(methylamino)‐substituted compounds. 2‐Nitroquinoline is aminated with LMA/PP to 2‐(methylamino)quinoline. The intermediate methylamino σ‐adducts of 3‐nitro‐ and 5,7‐ and 6,8‐dinitroquinoline are detected by 1H‐NMR spectroscopy. Quantum chemical calculations for the mononitroquinolines suggest that the experimentally observed regioselectivity of the methylamination is controlled by an interaction of frontal molecular orbitals (FMO) of the reagents.

Determination of photoelectron emission threshold in liquid methylamine: conduction band concept for electron-accepting energy states in polar solvents

Threshold potentials were measured for photoelectron emission from Pt, W, and Hg electrodes into liquid methylamine containing BuCl, BuBr, and N{sub 2}O as electron scavengers. From these values determined photoelectrochemically, the lowest unoccupied energy level (V{sub O}) of liquid methylamine at -50{degree}C was found to be -0.61 {plus minus} 0.03 eV relative to vacuum, which was 0.7 eV more positive than that of liquid ammonia at -55{degree}C, -1.29 eV. The V{sub O} value in either of the solvents was more positive than the solvation energy of a solvated electron in the corresponding solvent by 0.65 eV for methylamine and by less than 0.29 eV for ammonia. The unambiguous difference in the energetic separation between ammonia and methylamine (0.29 and 0.65 eV) and similar kinetic parameters of solvated electron electrodes in both solvents favored the conduction band model over the preexisting solvent trap model to account for the meaning of V{sub O} values evaluated from the photoelectron emission experiments.