124-40-3Relevant articles and documents
Combustion and sublimation calorimetric studies on acetylurea and trimethyl isocyanurate
Imamura, Akira,Murata, Shigeo,Sakiyama, Minoru
, p. 389 - 396 (1988)
Standard enthalpies of formation in the crystalline and gaseous states have been determined for acetylurea and trimethyl isocyanurate by oxygen bomb-combustion calorimetry and sublimation calorimetry.Derived values are as follows: .Stabilization energies related to intramolecular interaction between ?-electrons of carbonyl groups and lone-pair electrons of adjacent nitrogen atoms have been evaluated for acetamide and urea as well as for these compounds as enthalpy changes of "isodesmic" reactions using ethane as a reagent for the cleavage of CO-N bonds and are discussed.
Closkey, A. L. Mc,Boone, J. L.,Brotherton, R. J.
, p. 1766 - 1767 (1961)
Silicoaluminophosphate molecular sieve DNL-6: Synthesis with a novel template, N,N″-dimethylethylenediamine, and its catalytic application
Wu, Pengfei,Yang, Miao,Zhang, Wenna,Zeng, Shu,Gao, Mingbin,Xu, Shutao,Tian, Peng,Liu, Zhongmin
, p. 1511 - 1519 (2018)
DNL-6, a silicoaluminophosphate (SAPO) molecular sieve with RHO topology, was hydrothermally synthesized using a new structure-directing agent (SDA), N,N′-dimethylethylenediamine. The obtained samples were characterized by X-ray diffraction, X-ray fluorescence, X-ray photoelectron spectroscopy, scanning electron microscopy, and N2 adsorption, which indicated that the synthesized DNL-6s have high crystallinity and relatively high Si content ranging from 20% to 35%. Solid-state magic-angle-spinning (MAS) nuclear magnetic resonance (13C, 29Si, 27Al, 31P, and 27Al multiple-quantum (MQ)) was conducted to investigate the status of the SDA and local atomic environment in the as-synthesized DNL-6. Thermal analysis revealed the presence of a large amount of amines in the DNL-6 crystals (about 4.4 SDAs per α-cage), which was the reason for the formation of DNL-6 with an ultrahigh Si content (36.4% Si per mole). Interestingly, DNL-6 exhibited excellent catalytic performance for methanol amination. More than 88% methanol conversion and 85% methylamine plus dimethylamine selectivity could be achieved due to the combined contribution of strong acid sites, suitable acid distribution, and narrow pore dimensions of DNL-6.
Enhanced catalytic reduction of N-nitrosodimethylamine over bimetallic Pd-Ni catalysts
Chen, Huan,Li, Ting,Jiang, Fang,Wang, Zhe
, p. 167 - 177 (2016)
Catalytic reduction of N-nitrosodimethylamine (NDMA) was investigated over γ-Al2O3 supported bimetallic Pd-Ni catalysts (3%(PdxNi1-x)). NDMA could be reduced to dimethylamine over 3%(Pd0.8Ni0.2) with a metal-loading-normalized pseudo-first-order rate constant of 836 ± 21 L gme-1 h-1. Characterization results showed that the reducibility of PdO (or NiO) was improved by addition of Ni (or Pd) in 3%(PdxNi1-x); Pd-Ni ensembles were formed in 3%(PdxNi1-x) and there was an electronic transfer from Pd to Ni; metal dispersion was affected by the formation of Pd-Ni ensembles and a volcano curve of metal dispersion via Pd/Ni ratio was observed. The activity profiles demonstrated that TOF had a significant positive relationship with metal dispersion of 3%(PdxNi1-x), indicating high metal dispersion favor NDMA reduction. NDMA reduction over 3%(Pd0.8Ni0.2) catalyst could be described by Langmuir-Hinshelwood model, reflecting an adsorption controlled reduction mechanism. The reduction mechanism of NDMA over 3%(Pd0.8Ni0.2) catalyst was proposed to be that H2 was activated by Pd, and H spillover from Pd to Ni/NiO reduced NDMA though N-N cleavage.
Investigating the Underappreciated Hydrolytic Instability of 1,8-Diazabicyclo[5.4.0]undec-7-ene and Related Unsaturated Nitrogenous Bases
Hyde, Alan M.,Calabria, Ralph,Arvary, Rebecca,Wang, Xiao,Klapars, Artis
, p. 1860 - 1871 (2019)
The widespread use of amidine and guanidine bases in synthetic chemistry merits a thorough understanding of their chemical properties. The propensity of these reagents to hydrolyze under mild conditions and generate aminolactams and aminoureas, respectively, has not been adequately described previously. During the synthesis of uprifosbuvir (MK-3682), we became aware of this liability for 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) by observing the formation of an unexpected reaction impurity and traced the root cause to low levels of N-(3-aminopropyl)-?-caprolactam present in the commercial bottle. A controlled stability study over a period of two months at 25 °C demonstrated that, above a threshold water content, DBU steadily hydrolyzed over time. Rates of hydrolysis for DBU, 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and N,N,N′,N′-tetramethylguanidine (TMG) in organic, aqueous, and mixed solvent systems were then measured to gain a more general appreciation of what conditions to avoid in order to maintain their integrity. Our findings indicate that these bases are hydrolytically unstable in unbuffered and very basic solutions but become significantly more stable in buffered solutions at pH values below 11.6.
Efficient intramolecular nucleophilic catalysis in the base-catalyzed hydrolysis of o-(1-hydroxyalkyl)-N,N-dimethylbenzenesulfonamides
Drijfhout,Wagenaar,Engberts
, p. 2423 - 2426 (1986)
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Standard enthalpies of formation of crystalline dimethylammoniumdimethyldithiocarbamate and of dimethyldithiocarbamate complexes of copper(II) and nickel(II). The mean Cu-S and Ni-S bond-dissociation enthalpies
Silva, Manuel A. V. Ribeiro da,Reis, Ana M. M. V.,Faria, Rita I. M. C. P.
, p. 1365 - 1372 (1995)
The standard (p0 = 0.1 MPa) enthalpies of formation of crystalline dimethylammoniumdimethyldithiocarbamate and of the dimethyldithiocarbamate complexes of Ni(II) and Cu(II) were determined, at the temperature 298.15 K, by solution-reaction calorimetry.The enthalpy of "decomposition" of the dimethylammoniumdimethyldithiocarbamate salt and the enthalpies of sublimation of the metal complexes were measured by high-temperature microcalorimetry.From these values, the mean molar bond-dissociation enthalpies m>(M-S) were derived. .
Reactions of Carbonyl Compounds in Basic Solutions. Part 27.1 Alkaline Hydrolysis of Bridged Benz[de]isoquinolin-1-ones: Torsionally Distorted Lactams
Bowden, Keith,Hiscocks, Simon P.
, p. 96 - 97 (1997)
Rate coefficients have been measured for the alkaline hydrolysis of 2,3-ethanoxy- and 2,3-propanamino-2,3-dihydro-1H-benz[de]isoquinolin-1-ones? in 70% (v/v) dimethyl sulfoxide-water at several temperatures and of N,N-dimethyl-1-naphthamide in water: the relative rates of hydrolysis, activation parameters and other studies indicate the importance of the torsional distortion of the lactam nitrogen and steric 'bulk' factors in controlling reactivity.
One-pot synthesis of isoquinolinium salts by rhodium-catalyzed C-H bond activation: Application to the total synthesis of oxychelerythrine
Jayakumar, Jayachandran,Parthasarathy, Kanniyappan,Cheng, Chien-Hong
, p. 197 - 200 (2012)
It's worth its salt: The title reaction leads to the synthesis of highly substituted isoquinolinium salts (see scheme; Cp=Me5C 5). The reaction proceeds through a C-H activation and a subsequent annulation in the presence of a rhodium catalyst. The reaction mechanism is discussed as well as its application to the synthesis of the natural product oxychelerythrine.
Synthesis of Methylamines from Carbon Dioxide and Ammonia
Gredig, Silvia V.,Koeppel, Rene A.,Baiker, Alfons
, p. 73 - 74 (1995)
Methylamines were synthesized from carbon dioxide, hydrogen and ammonia over Cu-Al2O3 catalysts, affording a distribution of monomethylamine : dimethylamine : trimethylamine of 1 : 0.23 : 0.07.
Pushing the limits of energetic materials - The synthesis and characterization of dihydroxylammonium 5,5′-bistetrazole-1,1′- diolate
Fischer, Niko,Fischer, Dennis,Klapoetke, Thomas M.,Piercey, Davin G.,Stierstorfer, Joerg
, p. 20418 - 20422 (2012)
The safe preparation and characterization (XRD, NMR and vibrational spectroscopy, DSC, mass spectrometry, sensitivities) of a new explosive dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) that outperforms all other commonly used explosive materials is detailed. While much publicized high-performing explosives, such as octanitrocubane and CL-20, have been at the forefront of public awareness, this compound differs in that it is simple and cheap to prepare from commonly available chemicals. TKX-50 expands upon the newly exploited field of tetrazole oxide chemistry to produce a material that not only is easily prepared and exceedingly powerful, but also possesses the required thermal insensitivity, low toxicity, and safety of handling to replace the most commonly used military explosive, RDX (1,3,5-trinitro-1,3,5-triazacyclohexane). In addition, the crystal structures of the intermediates 5,5′-bistetrazole-1,1′-diol dihydrate, 5,5′-bistetrazole-1,1′-diol dimethanolate and dimethylammonium 5,5′-bistetrazole-1,1′-diolate were determined and presented.
UV direct photolysis of N-nitrosodimethylamine (NDMA): Kinetic and product study
Stefan, Mihaela I.,Bolton, James R.
, p. 1416 - 1426 (2002)
The ultraviolet (UV) direct photolysis of N-nitrosodimethylamine (NDMA) in aqueous solutions at pH 3 and 7 leads to dimethylamine, and nitrite and nitrate ions as the major degradation products. In addition, small amounts of formaldehyde, formic acid, and methylamine are formed. When the initial concentration of NDMA was 1 mM, only a 13% decrease in the total organic carbon (TOC) was measured at pH 7, whereas no significant change in the TOC was observed at pH 3. In the concentration range 0.01 - 1 mM NDMA, zero-order kinetics is obeyed, whereas first-order kinetics is followed at concentrations below 0.01 mM. The photolysis occurs much faster at pH 3 than at pH 7, which is explained by the difference in the quantum yields of the process at these two pH values. UV Direct photolysis is an efficient process for the removal of NDMA from contaminated waters, and electrical energy per order (EEO) values as low as 0.3 - 0.5 kWh/order/m3 were calculated for treatment of low concentrations of NDMA (0.001 mM).
Determination of 18O Exchange Accompanying Basic Hydrolysis of p-Toluamide and N,N-Dimethyl-p-toluamide
Slebocka-Tilk, H.,Brown, R. S.
, p. 1153 - 1156 (1988)
The base-catalyzed hydrolysis and 18O-exchange rate constants for p-toluamide (IV) and N,N-dimethyl-p-toluamide (V) have been determined under pseudo-first-order conditions as a function of -> at T = 100 deg C, μ = 1.0 M.Both sets of rate constants are linearly dependent on ->, and therefore the ratio of kex/khyd for IV and V does not change as a function of ->.For IV and V the ratios are 3.5 +/- 0.2 and 0.11 +/- 0.007 respectively.The fact that V shows substantial exchange suggests that the original formulation of the Deslongchamps stereoelectronic theory needs to be reassessed with respect to the conformational equilibration of the anionic tetrahedral addition intermediate produced from N,N-dimethylbenzamide and OH-.
Aminoborane polymers as precursors of C-N-B ceramic materials
Maya
, p. 1104 - 1107 (1988)
Aminoborane polymers were prepared via condensation reactions between polyfunctional amines and either triethylborane or tris(dimethylamino)borane. The products were characterized by chemical and spectroscopic analyses. The thermal degradation of these ma
Acid-catalysed chlorine transfer from N-chloramines to iodide ion: Experimental evidence for a predicted change in mechanism
Calvo, Paula,Crugeiras, Juan,Rios, Ana
, p. 4137 - 4142 (2010)
Rate constants for acid catalysis of the reactions of N-chlorodimethylamine (1), N-chloro-2,2,2-trifluoroethylamine (2) and N,N-dichlorotaurine (3) with iodide ion were determined in H2O at 25°C and I = 0.5 (NaClO 4). The failure to detect significant catalysis by general acids of chlorine transfer from 1 to the nucleophile, together with the observed inverse solvent deuterium isotope effect on the hydronium ion-catalysed reaction (k H/kD = 0.37), indicates that this process occurs by protonation of 1 in a fast equilibrium step, followed by rate determining chlorine transfer to iodide ion. The appearance of general acid catalysis for the reactions of 2 and 3 shows that increasing the leaving group ability leads to a change to a concerted mechanism, which is suggested to be enforced by the absence of a significant lifetime of the protonated chloramine intermediate in the presence of iodide ion.
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Norris,W.P.
, p. 1965 - 1972 (1972)
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Richarz et al.
, p. 2212 (1959)
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Absence of stereoelectronic control in the hydrolysis of fully and partially N-alkylated cyclic amidinium ions
Perrin, Charles L.,Thoburn, John D.
, p. 3140 - 3145 (1993)
Deslongchamps' hypothesis of stereoelectronic control states that preferential cleavage of a tetrahedral intermediate occurs when a leaving group is antiperiplanar to two lone pairs. Yet substantial amounts of lactams were produced from hydrolysis of cyclic amidines, through cleavage of the exocyclic C-N bond that is antiperiplanar to only one lone pair and syn to the other. It may be that proton transfer catalyzes nitrogen inversion, leading to an intermediate with two antiperiplanar lone pairs, such that the product distribution is indeed consistent with stereoelectronic control. To exclude this possibility, three cyclic amidinium ions (1a,b,c) with methyl groups at both nitrogens were synthesized, and their hydrolysis products in NaOD/D2O were analyzed by NMR. Although stereoelectronic control favors ring opening to amino amide 3, substantial amounts (40-90%) of lactam 4 are again produced. To exclude the possibility that lactam formation is due to a steric effect, hydrolysis of a cyclic N,N′-dimethyl amidine (2) was also studied, and 26-35% lactam is still produced. These results cannot be rationalized by assuming reaction via a boat conformer, since the lone pair of the ring nitrogen does not become antiperiplanar even in the boat form. Thus stereoelectronic control is not operative in amidine hydrolysis.
An Unusual Suppression of Trimethylamine Formation in the High Temperature Alkylation of Ammonia with Methanol over (NH4)3PW12O40
Nasikin, Mohammad,Nakamura, Ryuichi,Niiyama, Hiroo
, p. 209 - 212 (1993)
A synthesis of methylamines from ammonia and methanol was studied by using mainly the title heteropoly catalyst.Although at low temperatures below ca. 750 K the three methylamines (MMA, DMA, and TMA) were formed as usual, at higher temperatures the formation of TMA was completely suppressed.This unusual product selectivity was explained by the strong adsorption of TMA to the catalyst.
A new route to α-hetero β-enamino esters using a mild and convenient solvent-free process assisted by focused microwave irradiation
Dahmani, Zohra,Rahmouni, Mustapha,Brugidou, Richard,Bazureau, Jean Pierre,Hamelin, Jack
, p. 8453 - 8456 (1998)
New α-hetero β-enamino esters 5 (X = NH, O, S) are obtained in good to excellent yields by transamination reactions from ethyl 3-dimethylamino acrylate 2(a-c) and various volatile amines 3(a-e) using solvent-free conditions assisted by focused microwave irradiation. Most of the α-hetero β-enamino ester derivatives 3 present a (E)s-cis/trans conformation.
Adsorption and photocatalytic degradation of gas-phase UDMH under simulated sunlight by AgBr/TiO2/rGA
Ruomeng, Hou,Ying, Jia,Xiaomeng, Lv,Yuanzheng, Huang,Keke, Shen
, p. 12583 - 12594 (2021)
The degradation of UDMH has long been a concern for its harmful effects on humans and the environment. The current research on gas-phase UDMH treatment is limited and mainly focuses on ultraviolet light and high temperature environments, however the highly toxic substance NDMA is easily produced. In order to investigate the possibility of UDMH degradation in sunlight, AgBr/TiO2/rGA composites were prepared with the addition of different amounts of silver bromide. The highest UDMH conversion of AgBr/TiO2/rGA in humid air is 51%, much higher than the control group value of 24%, which can be ascribed to the synergy of adsorption and photocatalysis. The graphene and silver in AgBr/TiO2/rGA not only enhance the adsorption of light and UDMH, but also inhibit charge recombination and enhance electron-hole separation. More importantly, the temperature of the AgBr/TiO2/rGA composite was raised by the photothermal effect of graphene with promoted UDMH degradation efficiency. Furthermore, it is noted that NDMA was not detected in the optimal conditions.
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Shaw,Walker
, p. 4329 (1957)
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Synthesis and Characterization of Tungsten Nitrido Amido Guanidinato Complexes as Precursors for Chemical Vapor Deposition of WNxCy Thin Films
Nolan, Michelle M.,Touchton, Alexander J.,Richey, Nathaniel E.,Ghiviriga, Ion,Rocca, James R.,Abboud, Khalil A.,McElwee-White, Lisa
, p. 46 - 53 (2018)
Tungsten nitrido amido guanidinato complexes of the type WN(NR2)[(NR′)2C(NR2)]2 (R = Me, Et; R′ = iPr, Cy) were synthesized as precursors for aerosol-assisted chemical vapor deposition (AACVD) of WNxCy thin films. The reaction of tungsten nitrido amido complexes of the type WN(NR2)3 (R = Me, Et) with two equivalents of a carbodiimide R′N=C=NR′ (R′ = iPr, Cy) resulted in two insertions of a carbodiimide into W–N(amido) bonds, affording bis(guanidinato) amido nitrido tungsten complexes. These compounds were characterized by 14N NMR, indicating distinctive chemical shifts for each type of N-bound ligand. Crystallographic structure determination of WN(NMe2)[(NiPr)2C(NMe2)]2 showed the guanidinato ligands to be non-equivalent. The complex WN(NMe2)[(NiPr)2C(NMe2)]2 was demonstrated to serve as a precursor for AACVD of WNxCy thin films, resulting in featureless, X-ray amorphous thin films for growth temperatures 200–400 °C.
Reactions of Alkylnitrosoureas in Aqueous Solution
Snyder, John K.,Stock, Leon M.
, p. 1990 - 1999 (1980)
The acid- and base-catalyzed decompositions of N-methyl-, N,N'-dimethyl-, and N,N',N'-trimethyl-N-nitrosourea in aqueous solution have been studied.Below pH 2, the N-methyl compound undergoes both denitrosation and hydrolysis.The denitrosation yields methylurea and nitrous acid.The hydrolysis yields largely methylamine, nitrogen, and carbon dioxide.The acid-catalyzed denitrosation and hydrolysis of the trimethylnitrosourea are somewhat more rapid than the corresponding reactions of N-methyl-N-nitrosourea.The denitrosation of this compound yields trimethylurea and nitrous acid.The hydrolysis yields methanol, dimethylamine, nitrogen, and carbon dioxide.The solvent isotope effect, kH2O / kD2O = 1.3, and the absence of chloride ion catalysis suggest that the denitrosation reaction proceeds by a rate-determining proton transfer which is followed by the rapid loss of the nitroso group.The results for the hydrolysis reaction are compatible with a formulation in which a hydrate of the nitrosourea is protonated in a rate-determining step to form a tetrahedral intermediate which subsequently decomposes to yield methyldiazonium hydroxide and a carbamic acid derivative.The base-catalyzed reactions of the mono-, di-, and trimethylnitrosoureas are first order in hydroxide ion over a broad pH range.The hydrolysis of N-methyl-N-nitrosourea yields methanol and derivatives of carbamic acid.Salt effects on the reaction rate are negligible except for the influence of lithium ion.The rate constants for the hydrolysis of the mono- and dimethyl compounds depend upon the buffer concentration at pH 9.5.These constants reach limiting values.The rate constants for the hydrolysis of the trimethyl compound alsodepend upon the buffer concentration, but a limiting value is not achieved.The solvent isotope effect for the base-catalyzed reaction, the exchange reaction of water-18O with the carbonyl group of the urea, and the fact that N-methyl-N-nitrosourea is hydrolyzed about 2.2104 times more rapidly than N,N',N'-trimethyl-N-nitrosourea suggest that the hydrolysis occurs by a mechanism in which a tetrahedral intermediate is formed.Often, the formation of this intermediate is rate limiting.However, under certain conditions, its decomposition to methyldiazonium hydroxide and a carbamate anion which decompose to form methanol and the other products may be rate determining.
TiO2-reduced graphene oxide for the removal of gas-phase unsymmetrical dimethylhydrazine
Ruomeng, Hou,Ying, Jia,Yuanzheng, Huang,Keke, Shen,Huixin, Zhu
, p. 394 - 402 (2021)
Unsymmetrical dimethylhydrazine (UDMH) contaminated waste gas and related intermediates pose a great threat to human health. TiO2-reduced graphene oxide aerogel (rGA) samples with different graphene content levels were synthetized and characterized for the degradation of UDMH. The effects of GO content, humidity, and temperature were investigated under UV and VUV light, with highest UDMH conversion values of 68% and 95%, respectively. Compared with pure TiO2, the enhanced degradation activity of TiO2-rGA under UV light can be attributed to a synergetic effect between absorption and photocatalysis, while the high UDMH conversion under VUV light relies on photolysis and ozonation. The high oxygen-containing group content, rather than a high SSA, and electron trapping by graphene are key factors determining the outstanding performance of TiO2-rGA with 80 mg of GO. The prepared TiO2-graphene aerogels are promising for the degradation of gas-phase UDMH. This journal is
Degradation of gaseous unsymmetrical dimethylhydrazine by vacuum ultraviolet coupled with MnO2
Huang, Yuanzheng,Jia, Ying,Shen, Keke,Hou, Ruomeng,Zhang, Yongyong,Hou, Li'an
supporting information, p. 1194 - 1202 (2021/02/06)
In this study, α-, β-, and δ-MnO2 were prepared by a uniform hydrothermal method and then coupled with vacuum ultraviolet (VUV) for the degradation of gaseous unsymmetrical dimethylhydrazine (UDMH). The performance in the removal of UDMH, by-product distribution and mechanism were systematically investigated. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption/desorption, Field Emission Scanning Electron Microscopy (FE-SEM), Raman, thermogravimetry (TG), Fourier-transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) to investigate the factors affecting the catalytic activity. The results showed that O2 and H2O were essential for the removal of UDMH. Photooxidation and ozone catalytic oxidation contribute to the removal and mineralization of UDMH. The integrated process considerably improved the removal and mineralization of UDMH by ozone catalytic oxidation. More reactive oxygen species were generated in the integrated process. The catalytic activity of the prepared catalysts follows the order: δ-MnO2 > α-MnO2 > β-MnO2. δ-MnO2 displayed the highest removal rate of 100% and a CO2 concentration of 42 ppmv. The good performance of δ-MnO2 was mainly attributed to the large number of surface oxygen vacancies.
Electrochemical Reductive N-Methylation with CO2Enabled by a Molecular Catalyst
Rooney, Conor L.,Wu, Yueshen,Tao, Zixu,Wang, Hailiang
supporting information, p. 19983 - 19991 (2021/12/01)
The development of benign methylation reactions utilizing CO2 as a one-carbon building block would enable a more sustainable chemical industry. Electrochemical CO2 reduction has been extensively studied, but its application for reductive methylation reactions remains out of the scope of current electrocatalysis. Here, we report the first electrochemical reductive N-methylation reaction with CO2 and demonstrate its compatibility with amines, hydroxylamines, and hydrazine. Catalyzed by cobalt phthalocyanine molecules supported on carbon nanotubes, the N-methylation reaction proceeds in aqueous media via the chemical condensation of an electrophilic carbon intermediate, proposed to be adsorbed or near-electrode formaldehyde formed from the four-electron reduction of CO2, with nucleophilic nitrogenous reactants and subsequent reduction. By comparing various amines, we discover that the nucleophilicity of the amine reactant is a descriptor for the C-N coupling efficacy. We extend the scope of the reaction to be compatible with cheap and abundant nitro-compounds by developing a cascade reduction process in which CO2 and nitro-compounds are reduced concurrently to yield N-methylamines with high monomethylation selectivity via the overall transfer of 12 electrons and 12 protons.