Action Of Alkali Research Articles

Effects of synergistic modification using alkalis and guar gum on the pasting, rheological, and microstructural properties of germinated highland barley starch gels

Germination treatment of highland barley enhances its nutritional value while weakening the starch gel properties. This study aims to enhance the characteristics of germinated highland barley starch (GBS) by exploring the synergistic effects of two alkalis (Na2CO3 and NaHCO3) and guar gum (GG) on GBS gel properties. The combined action of alkalis and GG significantly improved the peak viscosity, setback viscosity, and hardness compared with GG alone. The highest G' and G" reached 998 and 204 Pa at 0.4% Na2CO3 addition, which were increased by nearly 44% and 50%, respectively. Fourier-transform infrared spectral analysis revealed that the alkalis strengthened interaction forces, particularly with intensified absorption peaks at 3200–3700 cm−1 and 1550–1750 cm−1. The Na2CO3 and NaHCO3 reduced the spin–spin relaxation time (T2), resulting in a dense starch gel network. This study contributes to enhancing the market application of GBS and offers innovative insights for modifying other starches.

Dependence of the properties of castable samples from low­cement silicon carbide castable before and after heat treatment on the action of alkalis at 1300 °C

The main properties and alkali resistance of silicon carbide castable samples heat­treated at temperatures of 110 and 1000 °C were investigated in comparison with the chamotte product, which is used for the same purposes in lining thermal units in contact with an aggressive environment.
 Samples of carbide­silicon castable after heat treatment at temperatures of 110 and 1000 °C were characterized by the following physical and chemical properties, respectively: wt. %: SiC — 84.60 and 79.70, Al2O3 — 13.65 and 13.60, CaO — 1.35 and 1.33; cold crushing strength — 42.2 and 67.5 N/mm2.
 The thermal conductivity of a silicon carbide castable sample heat­treated at a temperature of 1000 °C was determined to be 8.20 W/(m·K) and its thermal shock resistance (950 °C — water) was determined to be > 20 heat cycles.
 The studies of alkali resistance (to a mixture of alkalis Na2CO3 and K2CO3 in a ratio of 25:75) at a temperature of 1300 of carbide­silicon castable samples heat­treated at temperatures of 110 and 1000 °C in comparison with a sample of chamotte refractory, it was found that castable samples heat­treated at temperatures of 110 and 1000 °C are characterized by quite close alkali resistance (weight increase of 1.42 % and 1.5 %, respectively) and significantly higher (by ~ 4.3—4.5 times) alkali resistance than chamotte samples (weight increase of 6.5 %).
 It was established that castable samples after heat treatment at a temperature of 1000 °C after interaction with alkalis were characterized by a 1.6 times higher cold crushing strength compared to a castable sample heat­treated at a temperature of 110 °C.
 The study’s results made it possible to evaluate the performance of the silicon carbide castable in comparison with chamotte refractory during its operation in thermal units at consumers.

Synergistic effect of red mud, desulfurized gypsum and fly ash in cementitious materials: Mechanical performances and microstructure

The use of industrial solid waste to prepare cementitious materials can not only solve the pollution problem of ecological environment, but also help carbon emission reduction and sustainable development. In this work, typical alkaline solid waste - red mud (RM), sulfate solid waste - desulfurization gypsum (DG) and silicon-aluminum character solid waste - fly ash (FA) were used to prepare cementitious materials. The influence of synergistic effect of RM-DG-FA on the mechanical performances and hydration products of cementitious materials were systematically investigated. The hydration products were characterized and analyzed by XRD, TG, FTIR, MIP and SEM-EDS. It was found that the mechanical performances of cementitious materials were significantly improved under the synergistic effect of three kinds of solid wastes. When the content of the three solid wastes was 50%, the compressive strength of the cementitious materials at 28 d was 50.60 MPa, and the mechanical performances at each age were higher than the # 42.5 Portland cement standard. The microstructure results showed that under the synergistic action of alkali and sulfate, the active silicon and aluminum substances in RM and FA can quickly participate in the reaction, which makes the hydration degree of cementitious materials can move to the reaction direction with higher polymerization degree. The hydration products mainly included ettringite, C-S-H and C(N)-A-S-H gel. A large amount of gel and ettringite grew alternately, which reduced the porosity and formed a dense structure of the cementitious materials matrix, and its mechanical performances were improved. The leaching results showed that the synergistic effect also improved the solidification ability of the cementitious materials to Na+. In this work, the synergistic effect of RM-DG-FA significantly increased the utilization of solid wastes and the performances of cementitious materials. The research results provided a scientific basis for improving the utilization rate of alkaline solid wastes, sulfate solid wastes and silicon-aluminum character solid wastes and their collaborative utilization as building materials.

OBTAINING AN EMULSIFIER OF INVERSE EMULSIONS WITH A CORROSION INHIBITOR PROPERTIES

Reverse emulsions are widely used in oil production processes; moreover, due to a number of unique properties, they are used both in drilling and in killing wells, and for leveling the injectivity profile, as well as in repair and isolation works as a liquid packer. Most industrial emulsifiers belong to the class of fatty acid amides derived from natural and synthetic carboxylic acids and amines (primary and secondary) or amino alcohols. Given that many technological operations, such as killing with concentrated salt solutions (reverse emulsions are used as blocking fluids), treatment of the bottomhole zone with acid compositions (reverse emulsions are used as an acid diverter), are accompanied by intense corrosion of metal equipment and require additional costs for corrosion inhibition, we set ourselves the goal of developing an invert emulsifier with corrosion inhibitor properties. Using rapeseed oil and 2-[(2-aminoethyl)amino]ethanol as the initial compounds of the catalytic reaction under the action of alkali, amidoamine was obtained, which has the properties of an emulsifier of reverse emulsions and a corrosion inhibitor. Synthesis conditions are described and proof of the structure of the resulting compound is given. Its surface-active properties, emulsifying ability, as well as inhibitory activity under conditions of carbon dioxide corrosion were determined.

The Preparation Process and Hydration Mechanism of Steel Slag-Based Ultra-Fine Tailing Cementitious Filler.

Steel slag, desulphurised ash, desulphurised gypsum and ultra-fine iron tailing sand are common industrial solid wastes with low utilisation rates. Herein, industrial solid wastes (steel slag, desulphurised gypsum and desulphurised ash) were used as the main raw materials to prepare a gelling material and ultra-fine tailing was used as an aggregate to prepare a new type of cementing filler for mine filling. The optimal composition of the cementing filler was 75% steel slag, 16.5% desulphurised gypsum, 8.75% desulphurised ash, 1:4 binders and tailing mass ration and 70% concentration. The compressive strength of the 28-day sample reached 1.24 MPa, meeting the mine-filling requirements, while that of the 90-day sample was 3.16 MPa. The microscopic analysis results showed that a small amount of C3A reacted with the sulphate in the desulphurised gypsum to form ettringite at the early stage of hydration after the steel slag was activated by the desulphurisation by-products. In addition, C2S produced hydrated calcium silicate gel in an alkaline environment. As hydration proceeded, the sulphite in the desulphurised ash was converted to provide sulphate for the later sustained reaction. Under the long-term joint action of alkali and sulphate, the reactive silica-oxygen tetrahedra and alumina-oxygen tetrahedra depolymerised and then polymerised, further promoting the hydration reaction to generate hydrated calcium silicate gel and ettringite. The low-carbon and low-cost filler studied in this paper represents a new methodology for the synergistic utilisation of multiple forms of solid waste.

Synthesis and Study of the Properties of Porous Carbon–Carbon Nanocomposites with Nitrogen-Containing Carbon Nanofibers

The possibility of synthesizing carbon–carbon nanocomposites with nanofibers embedded in a carbon matrix by two-stage dehydrochlorination (under the action of alkali followed by carbonization) of a carbon-chain chloropolymer has been shown. Chlorinated polyvinyl chloride was used as the initial chloropolymer, and nitrogen-containing carbon nanofibers (N-CNFs) were used as a nanoscale component. The structure of the resulting nanocomposites was examined by electron microscopy and the texture parameters were studied using low-temperature nitrogen adsorption–desorption. The introduction of N-CNFs into the carbon matrix and the activation of the resulting carbon–carbon nanocomposite in an atmosphere of CO2 contributed to the formation of a micro- and mesoporous material with a specific surface area of ~1100 m2/g. It was shown that the resulting nanocomposites were characterized by high energy capacity and energy efficiency when tested as electrodes of electrochemical supercapacitors.

Analysis of the Formed Protective Layer Inhibiting Alkali Corrosion in Aluminosilicate Refractory Castables

This article analyzes the mechanism of the protective layer formation under the action of alkali in a refractory castable when ground quartz sand (GQS) is used as an admixture to produce refractory conventional castables (CC) and medium cement castables (MCC). It was found that, independently of the castable composition, the addition of GQS (2.5%) reduces the degree of K2CO3 dissolution at high temperature, and the released potassium reacts with the silica and forms a viscous potassium silicate glass, which reduces the mobility of alkali. The liquid phase formed filled some of the open pores and hindered the penetration of potassium into the deeper layers of the refractory castable. The thickness of the formed protective layer, after three cycles of the alkaline corrosion test, varies from 700 µm up to 1300 µm, depending on the castable composition.

4,5‐Dinitrosulfonefluorescein and related dyes: Kinetics of reversible rupture of the pyran ring and their interaction with lysozyme

AbstractFluorescein and sulfonefluorescein dyes are stable in solution within a wide pH range. Nucleophilic addition of the hydroxide (HO–) group to the nodal carbon atom is not typical of these compounds. They are also not prone to rupture of the pyran cycle under the action of alkali. However, the last‐named heterocycle readily opens at high pH values in the case of derivatives containing nitro groups in the xanthene moiety. Moreover, while in the case of nitrofluoresceins, for example, 4,5‐dinitrofluorescein, this reaction is irreversible, with 4,5‐dinitrosulfonefluorescein acidification of the alkaline solution immediately returns the visible absorption spectrum to that of the original hydroxyxanthene dye. We present a quantitative study of the kinetics of the pyran cycle rupture in aqueous alkali without and with micelles of a cationic surfactant. Also, both initial dye and reaction product were studied via the matrix‐assisted laser desorption/ionisation time‐of‐flight (MALDI‐ToF) technique. The second part of the article is devoted to the interaction of 4,5‐dinitrosulfonefluorescein and other dyes of similar structure with lysozyme basing on the MALDI‐ToF mass spectrometry. This made it possible to arrange the dyes according to their affinity for the protein and draw some conclusions about the nature of the association of the dye with lysozyme.

Study on stability of produced water in ASP flooding based on critical micellar theory

The basic properties of produced water and the effect of oil displacement agent for its stability were obtained, through measuring and analyzing water quality characteristics, relationship between critical micelle concentration-oil displacement agent, temperature, pH and content of inorganic salt, particle size distribution and morphology of Nan4-8 and Sanyuan-6 alkali-surfactant-polymer (ASP) produced water of Daqing Oilfield. The critical micelle concentration of ASP flooding was less than its own concentration, and the double bilayer was formed in system. Critical micelle concentration of ASP produced water was less affected by the system temperature and greatly affected by pH. Polymer increases viscosity of produced water and has the properties of surfactant, which partially hydrolyzes under the action of alkali to form polyelectrolyte and promotes the formation of double electric layer. Therefore, the coalescence of oil droplets in ASP produced water is difficult, and the stability is greatly enhanced. ASP produced water contains a large amount of inorganic salts, which can shield the electrostatic repulsion between the surfactant ion head groups, compresses the thickness of the double electric layer, and promotes the formation of surfactant micelles. When it settles after a certain period of time, part of ASP produced water has a particle size distribution less than 100 nm, the micelles are generated in the system, which enhances the stability of ASP produced water.

Synergistic Action of Alkalis Improve the Quality Hemicellulose Extraction from Sugarcane Bagasse for the Production of Xylooligosaccharides

The present study demonstrates an effective alkaline protocol for the extraction of quality hemicellulose using NaOH and NH4OH combination from sugarcane bagasse for the production of xylooligosaacharides (XOs). For achieving maximum recovery of hemicellulose, the statistical optimization technique was adapted, while considering alkali concentration and temperature, as important process parameters, for all of the alkaline tested protocols like individual or mixed alkalis. The comparative study exposed that mixed alkalis promoted higher recovery of hemicellulose (68% wt xylose), which is relatively higher (up to 1.3-times) than the individual alkali protocols, such that it contained predominantly the xylose (xyl/ara ratio was 3.94) in the form of xylan. In perception, the synergistic action of different alkalis (weak and strong bases) have strongly influenced the selective cleavage of lignin-carbohydrate linkages, thereby enabling the higher release of hemicellulose under the modest reaction conditions (10% alkali conc. and 120 °C). Moreover, the analytical characterization witnessed that it is composed of majorly xylose with less or no undesired residual biomass constituents, including lignin. Upon evaluating the resultant hemicelluloses for XOs production via acidic hydrolysis, the hemicellulose obtained through the mixed alkalis protocol exhibited exceptional, resulting in ~ 13% wt XOs yield with a high degree of polymerization (2–4 units); it is relatively ~ 2.8-times higher than the result of other hemicelluloses. In addition, the formation of gaseous ammonia during the reaction of the mixed alkalis could potentially contribute to the reduction of overall processing cost through recovery and reuse strategy during the large-scale XOs production.

SOME REGULARITIES OF WEAR OF COMPLEXED SURFACES, BASES AND MIDDLE BANDS OF DETAILS OF CONICAL TRIBOSYSTEMS

The basics and average jumpers of the rotor and the body are studied, which perform the following functions: provide autonomous work of two sections; carry out autonomous operation of circulation of high and low pressure alkaline; is a frame in which other parts are held to support all functions of the high pressure feeder; support the difference in pressure between the sections. Thus, indicative drawings of the wear of the working surfaces of the rotor and the shell between the windows are formed by the action of alkali in the gap, and its value (at a constant gap) depends on the length of the gap. hus, indicative drawings of the wear of the working surfaces of the rotor and the shell between the windows are formed by the action of alkali in the gap, and its value (at a constant gap) depends on the length of the gap. With a minimum clearance gap between the rotor sections and the feeder housing, the flow rate and the flow rate of the alkali are maximal, and at the maximum length of the gap the flow rate and the flow rate of the alkali are minimal and, consequently, the wear is small. Due to the sinusoidal gap change law, the uneven wear of the working surfaces of the rotor and the body along the length of the circle can be explained.It has been established that on the two working surfaces of the rotor and the body there is a hydro-abrasive wear due to leakage of alkali in the mobile gap and shock hydraulic abrasive wear as a result of the formation of hydraulic shocks in the rotor pocket. The values of these types of wear depend on the time of compensation gap. Compensation for wear on these polling stations is higher than at other polling stations.The nature of the wear and tear of the bases and middle jumpers of the rotor and the body is revealed. The value of this wear is linear in time and its size is comparable to wear on other sections with compulsory micro-impulse gap compensation and not comparable (much less) when compensating for the critical gap. Wear on the bases and mid-joints of the rotor and the body occurs under the influence of hydraulic wear with the forced transfer of solid particles to the friction zone. With an uneven height of 8-10 microns and a minimum clearance of 50-100 microns, abrasive particles are constantly and coercive at these gaps due to cyclic hydraulic shocks. The presence of abrasive particles in the friction zone results in the destruction of both the particles itself and intercontact friction pairs of the surfaces of the bases and middle jumpers of the rotor and the case. As a result, there is a new kind of abrasive wear – hydro-abrasive deterioration in a narrow slit with the forced passage of solid particles into the friction zone.

Influence of different state alkali and alkaline earth metal on chemical structure of Zhundong coal char pyrolyzed at elevated pressures

The investigation on the evolution of coal char structure is the prerequisite in evaluating the catalytic action of alkali and alkaline earth metal (AAEM) during pressurized pyrolysis. In the study, Zhundong raw coal samples were first treated using the chemical fractionation method, and then pyrolyzed at 0.1 MPa–3 MPa in a pressurized thermogravimetric analyzer (PTGA). In order to understand the effect of AAEM on the chemical structure of the samples at elevated pyrolysis pressures, the Fourier transform infrared spectroscopy (FT-IR), the Raman spectroscopy and a series of original structure parameters were employed. It is indicated that over 1 MPa, water-soluble AAEM inhibited the decomposition of phenolic hydroxyl group, while ion exchangeable AAEM inhibited the decomposition of carboxyl functional groups and catalyzed the cracking of aliphatic long chains. The influence of pressure on conversion of functional groups was various at different pyrolysis temperatures. Under 1 MPa, the pressure had distinct influences on the carbon skeleton structure of coal char and mainly promoted the graphitization process of samples during pyrolysis. Besides, the ratios of phenolic hydroxyl, ether and aliphatic aromatic in char were not sensitive with elevated pressure.

Quantum-chemical Study of the Mechanisms of Organic Reactions: VIII. On the Reaction of Ethane-1,2-dithiol with 1,3-Dichlorobut-2-ene in the Hydrazine Hydrate–KOH System

A mechanism of the reaction of 1,3-dichlorobut-2-ene with 1,2-ethanedithiol in the hydrazine hydrate–KOH system is proposed on the basis of the results of DFT calculations at the В3LYP/6-311++G(d,p) level of theory. It is shown that this reaction involves several consecutive stages, including the nucleophilic substitution of the chlorine atom on the sp3-carbon atom by a sulfur atom (SN2 mechanism) to form a monosubstitution product, which is dehydrochlorinated under the action of alkali by the bimolecular mechanism E2 to form an acetylene intermediate. The latter undergoes ring closure via the intramolecular nucleophilic attack of the free thiolate group on the β-carbon atom of the acetylene fragment, yielding the final dithiane derivative.

КВАНТОВО-ХИМИЧЕСКОЕ ИЗУЧЕНИЕ ВЗАИМОДЕЙСТВИЯ 1,2-ЭТАНДИТИОЛА С 1,3-ДИХЛОРБУТЕНОМ-2 В СИСТЕМЕ ГИДРАЗИНГИДРАТКОН

According to the results of quantum-chemical studies in the framework of the theory
 of functional density of the electron density using the B3LYP / 6-311 ++ G (d, p) method, a theoretical
 mechanism of the reaction of 1,3-dichlorobutene-2 with 1,2-ethanedithiol in the hydrazine hydrateKOH system has been proposed. It has been shown that this interaction proceeds sequentially in several stages, including the nucleophilic substitution of the chlorine atom of the sp3 hybridized carbon
 atom to the sulfur atom with the formation of a monosubstitution product (SN2 mechanism), which under the action of alkali undergoes deprotonation of the methylene group to form an allyl carbanion .
 The resulting carbanion, due to the migration of hydrogen and the removal of chlorine, is converted
 into an allene derivative, which as a result of the intramolecular nucleophilic attack of the free
 thiolate group on the central carbon atom of the allene fragment closes into the final dithian cycle.

One-dimensional magnetic nanocomposites with attapulgites as templates: Growth, formation mechanism and magnetic alignment

Magnetic nanocomposite composed of attapulgite and Fe3O4 was synthesized by a simple and facile co-precipitation method. Its structure and morphology was verified using X-ray diffraction, transmission electron microscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. Although the difficulty of forming uniform Fe3O4 on the attapulgite surface was discussed in detail in this study, one-dimensional magnetic nanorod with attapulgites as core and Fe3O4 as uniform shell was implemented for the first time using a cationic polymer surfactant, polyethylenimine. Polyethylenimine concentration, Fe3+/Fe2+ concentration and temperature were controlled to investigate the morphological evolutions of this nanocomposite. It was found that a uniform shell could be available with thickness tuning from 10 nm to 40 nm when Fe3+ concentration ranged from 0.01 mol/L to 0.03 mol/L meanwhile the polyethylenimine concentration was kept at 0.2 mg/mL and the temperature was kept at 60–80 °C. Finally, a possible mechanism for the formation of the Fe3O4 shell was suggested. The polyethylenimine on the surface of the attapulgites first adsorbed Fe3+/Fe2+ and then released under the action of alkali. It acted as a linker for the Fe3O4 nanoparticles nucleation in situ. The synthesized one-dimensional nanocomposites exhibit the superparamagnetism and fast response to an external magnetic field. The alignment of attapulgite-Fe3O4 one-dimensional nanocomposite along the external magnetic field was demonstrated. It provides promising candidates for building blocks and functional devices, which are low cost, non-toxic and eco-friendly, and opens the door for the application of attapulgite as one-dimensional nanomaterials.

An experimental study on the floating motion of oil drop in ASP solution

Alkali-surfactant-polymer (ASP) flooding is a high-efficient chemical enhanced oil recovery technology and has been utilized on a large scale in the oilfield. Nevertheless, the produced water treatment from ASP flooding is a great challenge to be resolved. In this paper, the separation mechanism and floating rules of oil droplet in ASP flooding produced liquid are experimentally investigated. The synergistic action of alkali, surfactant and polymer is systematically explored. The results showed that the electrostatic shielding effect induced by excessive sodium ions will lead to the curl of polymer chains and the decrease of viscosity, as a result the floating speed of oil droplet surrounded by ASP solution will increase. The solubilization of surfactant micelles will also reduce the viscosity of ASP solution, which is benefit to the separation of oil droplet in ASP flooding produced liquid. Furthermore, correction for the drag coefficient of oil droplet in ASP solution is developed.

Generation of biocompatible nanogold using H2O2–starch and their catalytic/antimicrobial activities

Biocompatible nanogold (AuNPs) have gained considerable attention for potential applications in nano-medicine due to their characteristic size dependent chemical, electronic and optical properties. Herein, energy saving and simple strategy was proposed for simultaneous preparation of nanogold suspension using starch polymer as bio-synthon and protective envelope for AuNPs, at room temperature·H2O2 was used as enhancer for the reducibility and accessibility of starch by oxidative degradation of its macromolecules to more reducible fragments. While, the nucleation of nanoparticles was motivated by the action of alkali. The reducible fragments in solution were detected via measurements of reducing sugars content. Preparation of nanogold was investigated by absorbance spectra, transmission microscope and zetasizer instrument. Size of AuNPs was a function of reactants' concentration and the smallest sized AuNPs (11.74nm) was produced by using 2g/L starch, 1% H2O2 and 10g/L NaOH, where, reducing sugars detected to be 0.46g/L. The produced nanogold showed good catalytic activity in reduction of p-nitroaniline and accelerate the reduction percentage from 12.1% to 39.2% in 2h. The prepared AuNPs displayed antibacterial efficacy towards different bacterial species and the MIC was evaluated to be 960µL/mL against S. aureus.

Study of Alkali Resistance of Refractory Materials Used in Boilers Operating on Wood Fuel

Using the ASTM C 454–83 method alkali resistance is studied for various refractories (chamotte brick, traditional and medium-cement chamotte concrete) used most often in power generation boilers operating on wood fuel. Resistance to alkali of medium-cement concrete developed by the authors with a filler prepared from sinter grade Gorkal-50 (produced by the Gorka Plant, Poland) is also studied. It is established that use of milled quartz sand additive improves resistance of the test cement significantly towards the action of alkaline salt (K2CO3 is used in the work) at 1100°C. It is shown that the test additive during action of alkali facilitates formation of a protective layer that prevents penetration of K2CO3 decomposition products into the material structure.

Weight reduction of polyester fabric using sodium hydroxide solutions with additives cetyltrimethylammonium bromide and [BMIM]Cl

Polyethylene terephthalate (PET) fibre is largely used in the textile apparel industry. Treatment of PET fibres by sodium hydroxide solution is a well-known process giving smooth surface with decrease in the fibre diameter. Hydrolytic scission of ester linkages of the polyester chains on the fibre surface takes place. Appropriate effects are achieved through monitoring of alkali concentration, time and temperature of the process without any significant deterioration of important fibre characteristics. Addition of various chemicals enhances the hydrolytic action of alkali. PET fabric was treated with aqueous as well as methanolic solutions of sodium hydroxide in the presence of additives namely, a quaternary ammonium compound, cetyltrimethylammonium bromide (CTAB) and an ionic liquid, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). The process parameters were optimized for desired level of treatment and the effect evaluated in terms of reduction in fabric weight and SEM images of the samples. Weak methanolic NaOH showed greater effect than aqueous NaOH solution. Also, the addition of [BMIM]Cl enhanced the effect better than CTAB. Results of ANOVA analysis showed that temperature played very significant role and time was of less significance for treatment using [BMIM]Cl. Both the parameters were insignificant for the conventional and CTAB treatments. Thus, the use of novel eco-friendly additive [BMIM]Cl can cause conservation in terms of time and temperature in this commercially important process.

Hydrolytic Heterocyclization of the 1,1,2,3,3‐Pentacyanopropene Salts

Salts of 5‐amino‐4‐cyano‐3‐dicyanomethylene‐2‐pyrrolinone are formed by action of dilute aqueous solutions of alkalis on pentacyanopropenide‐anion salts. These cyclic salts are transformed to 2,6‐diamino‐3,5‐dicyanoisonicotinates by subsequent action of alkalis.