Acetylenic Alcohols Research Articles

Mechanism of degradation of propargyl alcohol by acid-catalysed hydrolysis and corrosion inhibition efficiency of propargyl alcohol intermediates for carbon steel in hydrochloric acid

Acetylenic alcohols are one of the most important groups of film-forming corrosion inhibitors for carbon steel in hydrochloric acid (HCl). The inhibition mechanism of acetylenic alcohols has been widely discussed for more than 50 years, however, it is not well-understood, particularly with regard to the chemical degradation reactions of acetylenic alcohols in HCl solution. In the present paper, proton nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) techniques were used to investigate the mechanism and the rate of degradation of propargyl alcohol in 3.6–10.8 M HCl at 20–95 °C. Several water-soluble products, such as 1-hydroxypropan-2-one, 2-chloroprop-2-en-1-ol, 2,2-dichloropropan-1-ol and 2-chloropropane-1,2-diol were formed via the electrophilic acid-catalysed addition of HCl and water to the alkyne. Some intermediates further polymerize to form water-insoluble polymers, such as poly (propargyl alcohol), poly (allyl alcohol) and poly (acrolein). The hydrolysis half-life constants of propargyl alcohol decreased with increasing HCl concentration and temperature. The inhibition efficiency (η) of propargyl alcohol and its precursors for carbon steel in 3.6 M and 7.83 M HCl was studied. The critical role of acrolein intermediates on the corrosion performance of propargyl alcohol in hydrochloric acid was identified. Products of propargyl alcohol hydrolysis, 1-hydroxypropan-2-one and 2-chloroprop-2-en-1-ol are poor corrosion inhibitors. However, acrolein and its reactive intermediates are good corrosion inhibitors with inhibitor efficiency, η in the range from 97.69 ± 0.4 % for fresh acrolein to η = 97.94 ± 0.8 % for aged acrolein.

Conjugated Cationic Pp-x Formed on g-C3N4 for Photocatalyzed Water Splitting.

Polycationic Pp-x@g-C3N4 composite was synthesized through an in situ polymerization process of N-alkylpyridinium acetylenic alcohol bromide (p-x) above the surface of g-C3N4. The structure of p-0 and the Pp-x@g-C3N4 properties were checked by modern technologies. Photocatalytic tests of Pp-x@g-C3N4 in water splitting unveiled much better Pp-x@g-C3N4 hydrogen evolution activities by comparison with both g-C3N4 and Pp-0. The hydrogen production by Pp-0@g-C3N4 was 1654.5 μmol h-1 g-1, which is ∼26- and 22-fold greater in relation to what g-C3N4 and Pp-0 produced (62.7 and 75.0 μmol h-1 g-1, respectively), suggesting strong bilateral and synergistic interactions of g-C3N4 with Pp-0. Although the lengthening methylene chain in the polymers weakened the hydrogen generation ability of Pp-x@g-C3N4, the conjugated double bonds, solubilization, and dispersion of Pp-x polycationic surfactants made Pp-x@g-C3N4 superior to g-C3N4 in water splitting. Due to the readily available raw materials, a simple way of preparation (starting chemicals to p-0 to Pp-0@g-C3N4), high photocatalysis efficiency, light irritation stability, recyclable ability, and low toxicity, Pp-0@g-C3N4 is a good candidate for water splitting.

Influence of the Effectiveness and Selectivity of Acetylenic Alcohols on Coal Flotation with Different Feed Density

Influence of the Effectiveness and Selectivity of Acetylenic Alcohols on Coal Flotation with Different Feed Density

SYNTHESIS OF AROMATIC ACETYLENE ALCOHOLS USING COMPLEX CATALYTIC SYSTEMS

Some cyclic ketones (cyclopentanone, cyclohexanone, 2-methylcyclohexanone, menthol, camphor and adamantanone) enantioselective alkynylation reactions with phenylacetylene have been studied in the presence of complex catalytic systems - Zn(OTf)2/NЕt3/MeCN, 3,3′-Ph2BINOL-2Li/TGF and BuLi/KOtBu/TGF. Synthesis were performed new aromatic acetylene alcohols – 1-(2-phenylathinyl) cyclopentanol (1), 1-(2-phenylethinyl)cyclohexanol (2), 2-methyl-1-(2-phenylethinyl)cyclohexanol (3), 2-isopropyl-5-methyl-1-(2-phenylethinyl)cyclohexanol (4), 1,7,7,-trimethyl-2-(2-phenylethinyl)bicyclo [2.2.1] heptanol-2 (5) and 2-phenylethinyltricyclo [3,3,1.03,7]nonanol-2 (6). Synthesis reactions of aromatic acetylene alcohols, activation energies were determined, kinetics of chemical changes were analyzed, reaction mechanisms were proposed. The course of the reactions and the effect of the selected ketone molecule size, structure and number of rings on the product yield were analyzed. A series of catalytic activity of the applied complex catalytic systems has been developed.

Synthesis of heterocyclic bromacetylene alcohols and their acryl -, methacryl ethers

The article presents a method for obtaining heterocyclic bromoacetylenic alcohols by the action of sodium hypobromide on cyclic and heterocyclic acetylene alcohols, as well as their acrylic and methacrylic esters using lithium aluminum complexes. The composition and structure of the obtained products were confirmed by the data of elemental analysis, IR and PMR spectra. As a result of the study, it was found that in the presence of lithium aluminum hydride, the product yield in all cases is higher than 80 %.

ETHINYLATION REACTIONS OF SOME ALDEHYDES IN THE PRESENCE OF PHENYLACETYLENE USING HIGH-BASE CATALYTIC SYSTEMS

The aim of the research work is the development of synthesis methods of aromatic acetylene alcohols and their various derivatives using different catalytic systems and also, determining their structure, physico-chemical and biological properties. The most effective way of synthesizing AAA is determined using selected complex catalytic systems and also, the range of catalytic activity of used catalysts is created. Acetic aldehyde, benzaldehyde and cyclohexonal, high-base catalytic systems − MOH/ДМСО∙H2O and M2CO3/ДMСO∙H2O with phenylacetylene reaction of enantioselective etynilation were investiged. Efficiency and course of chemical reaction in the process of formation acetylene alcohol affection of temperature, reaction duration, solvents, catalysts and constituents, their number and nature effects. Based on the results obtained to increase the acetylene alcohol production, reduce the amount of supplementary and intermediate products, the most favorable conditions were found

STIMULATING AND INHIBITING EFFECTS ON PLANTS OF SOME ACETYLENIC AMINO ALCOHOLS AND SALTS GUIDAMONACI

The herbicidal effects of aminopentinols, aminohexinols and some synthesized acetylene aminospirths, hydrochloride compounds, as well as the biological activity of their effects in relation to such important crops as cotton and corn were studied. During pretreatment of seeds and weeds, it was found that the studied drugs show different herbicidal activity in relation to annual dicotyledonous and annual grain weeds, depending on their chemical composition and dosage. It has been established that many ammonium salts of acetylene amino alcohols have high biological activity and that their use, depending on the chemical structure and quantity, has biological effects. To determine the biological activity of the studied drugs, the authors used a well-known method of biotestylation in wheat coleoptile. Preemergence treatment by solutions of abovementioned preparates in dependence on their chemical structure and dose have rendered different action on the growth leguminous (nut) and cereals (wheat, sorghum) plants.

Substantiation of the Erdenetiyn-Ovoo copper-molybdenum ore flotation technology with the use of tertiary acetylene alcohol

The article presents the results of a study of the factors affecting the efficiency of the copper-molybdenum ore flotation. The objective of this work was to substantiate and develop a reagent mode for flotation of the Erdenetiyn-Ovoo porphyry copper ores, which makes possible extracting main copper and molybdenum minerals into corresponding concentrates more fully and selectively. It is shown that the use of a DC-80 (2-methyl-3-butin-2-ol) flotation reagent in assosiation with the main base mode reagents — an AERO MX-5152 (a mixture of allyl ethers of xanthogenic acids with n-butyloxycarbonyl-O-n-butylthionocarbamate) combined nonionized collector, a BK-901B (a composition of dialkyldithiophosphate and O,N-dialkyldithiocarbamate) blending ionized collector; diesel fuel; a MIBC (methyl isobutyl carbinol) frother; sodium sulphide Na2S as a modifier and lime СаО as a pH regulator of the medium allows obtaining a noticeable, economically sound additional recovery of both copper and molybdenum. Quantum chemical calculations have permitted to establish an important feature of the mechanism of interaction between the DC-80 molecules that can form stronger complexes based on -bonds with metal cations of sulfide minerals in comparison with allyl ethers of xanthogenic acids. The energy indicators of the formation of bonds between Cu2S, the DC-80 molecules and allyl ether of xanthic acid were calculated. There were shown the models of the assumed interaction of small mineral particles with air bubbles during flotation, which are determined by physical and chemical properties of the molecules of acetylene-containing reagents. The principal difference between the properties of the foam bubbles formed by acetylene-containing molecules for at least 50% and that of the ordinary foam bubbles formed by standard frothers has been demonstrated in the view of the mechanism of their fixing on the surface of small particles of sulfide minerals and the surface of the bubbles. The optimal flotation mode, comprising a DC-80 reagent, BK-901B and AERO MX-5152 base collectors has been developed. The application of this mode will allow increasing the copper and molybdenum recovery into concentrates by 0.62% and 5.76%, respectively, reducing the flotation time by 35–40%, and improving the quality of resulting concentrates. Based on the research results, it is recommended to incorporate the DC-80 acetylene reagent into the basic flotation mode for conducting pilot tests at the Erdenet Mining Corporation enterprises (Mongolia).

Palladium-Phosphorus Nanoparticles as Effective Catalysts of the Chemoselective Hydrogenation of Alkynols

The effect of the composition of the catalytic system and reaction conditions on the properties of phosphorus-modified palladium catalysts in hydrogenations of alkynols was studied. Modification with phosphorus increased the activity and turnover number of palladium catalysts in the hydrogenation of the model compound 2-methyl-3-butyn-2-ol (MBY) without any reduction in the selectivity to 2-methyl-3-butene-2-ol at 95–98% MBY conversion. The promoting effect of phosphorus on the properties of the palladium catalyst is caused not only by an increase in the particle size, but also, probably, by a change in the energy of interaction of reagents with the active sites. Hypotheses on the nature of the carriers of catalytic activity in Pd–P particles were discriminated using kinetic methods with the differential selectivity of catalytic systems as the main measured parameter under the conditions of competition between two alkynols. The hydrogenation of acetylenic alcohols involves only one of the two potentially active forms in Pd–P nanoparticles—Pd(0) clusters, whereas the hydrogenation of the resulting allyl alcohols involves both Pd(0) clusters and palladium phosphides.

New acetylenic metabolites from the toxic mushroom Tricholoma pardinum

Four unprecedented acetylenic alcohols, (Z)-non-7-en-5-yn-1,2,4-triol (1), (Z)-non-7-en-5-yn-1,4-diol (2), (Z)-1,2-dihydroxynon-7-en-5-yn-4-one (3), and (Z)-1-hydroxynon-7-en-5-yn-4-one (4) were isolated from the poisonous mushroom Tricholoma pardinum (Agaricales, Basidiomycota), together with the known compounds 1H-indole-3-carbaldehyde (5) and 6-hydroxy-1H-indole-3-carbaldehyde (6). Their structures were determined by NMR and IR spectroscopy, and mass spectrometry. The crude acetone extract of the mushroom showed potent anti-arthropod activity against Tetranychus urticae (Acarinae), a dangerous crop pest.

The synthesis of pyridine bases based on acetylenic alcohols

The synthesis of pyridine bases based on acetylenic alcohols

Improvement of porphyry copper flotation efficiency with auxiliary collecting agents based on acetylene alcohols

Improvement of porphyry copper flotation efficiency with auxiliary collecting agents based on acetylene alcohols

Total synthesis of cytotoxic pyranone B

The first stereoselective total synthesis of cytotoxic diacetylene pyranone B is described. The key steps involved in the synthesis are base-induced elimination protocol to generate the chiral acetylenic alcohol and selective cross-coupling of unsymmetrical terminal acetylenes.

Cleavage of C–C and C–O Bonds to Form C–C Bonds: Direct Cross‐Coupling between Acetylenic Alcohols and Benzylic Carbonates

A palladium‐catalyzed cross‐coupling reaction between C(sp) and C(sp3) centers was achieved in excellent yields via C–C bond cleavage and C–O bond cleavage. This procedure uses relatively stable acetylenic alcohols as reactants instead of unstable/volatile terminal alkynes. The use of benzylic carbonates also avoids the involvement of benzyl halides, making this method more practical in synthesis. Ligands play an important role in the procedure and K2CO3 accelerates the reaction.

Synthesis of Pp-16@Ag/AgCl of high performance photocatalyst particles for decomposition of Rhodamine B and fast green dyes

Poly (N-hexadecyl pyridine acetylenic alcohols bromide)/silver/silver chloride (Pp-16@Ag/AgCl) composite as a novel photocatalyst is fabricated by in situ polymerization of N-hexadecyl pyridinium acetylenic alcohols bromide (p-16) on the surface of Ag/AgCl. The prepared composite photocatalysts were characterized by multiple techniques. The results indicated that Pp-16 layer was formed on the surface of Ag/AgCl, which promoted photoinduced electron−hole pairs separation and endowed the compost catalyst with high phtocatalysis capacity. The phtocatalysis evaluation tests manifested that 99% of Rhodamine B (RhB) and Fast green (FG) were effectively degraded in minutes by Pp-16@Ag/AgCl, while 51% of RhB and 69% of FG Ag/AgCl were depcompoed by Ag/AgCl. The activity of Pp-16@Ag/AgCl was almost kept in four cycles of reutilization. Apart from the dosage of Pp-16@Ag/AgCl and irritation time, pH value of the solution also affected the decomposition efficiency due to the different charge density on the two dyes. The probe of photocatalysis mechanism elaborated that photogenerated hole and superoxide radical were the main active species in the degradation of RhB and FG by Pp-16@Ag/AgCl, and Pp-16 could promote the generation of •O2−. Therefore, Pp-16@Ag/AgCl demonstrates high catalysis activity under ultraviolet light irradiation.

PROTECTIVE PROPERTIES OF «SOLING» SERIES INHIBITORS IN ACIDIC MEDIA CONTAINING HYDROGEN SULPHIDE

The work presents the results of the study of a number of inhibitory compositions of the “Soling” series based on acetylenic alcohols and their mixtures with nitrogen-containing compounds of various types in a hydrochloric acid (0.1 M HCl) containing 100 ppm of hydrogen sulphide. Gravimetric tests and electrochemical studies were performed on mild steel St3 at ambient temperature. The exposure time of the samples was 24 h. Polarization curves were obtained in a three-electrode cell, using the SOLARTRON 1280 C electrochemical measuring complex. The following protective compositions were studied: Soling IK-1 on the basis of unsaturated alcohol in a mixture with sulfur-containing amide in an aqueous medium; Soling IK-2 on the basis of unsaturated alcohol with additions of quaternary ammonium salt and complexone; Soling IK-3 on the basis of unsaturated alcohol in the system of organic solvents, as well as Soling IK-4(A) on the basis of a high-molecular nitrogen-containing surfactant (molecular weight from 300 to 400) with additions of unsaturated alcohol in a system of organic solvents and Soling IR-4(B) based on a high-molecular nitrogen-containing surfactant with a molecular weight of up to 300. It has been obtained that the use of unsaturated alcohols without additives in the presence of hydrogen sulphide is possible only at sufficiently high concentrations. At low concentrations, the corrosion process is markedly stimulated (composition IK-3). In a mixture with nitrogen-containing compounds (compositions IK-1, IK-2, IK-4(A)) it is possible to achieve high protective effect allowing the use of these compositions for hydrogen sulfide-containing media. The most effective are the compositions IK-2 and IK-4(A), for which the protective effect reaches the values of 97 and 90%, respectively, and also these compositions in the whole range of concentrations studied eliminate the appearance of hydrogen blistering. In most cases, the studied compositions are characterized by effective inhibition of the partial cathodic process. For SolIng IK-2 inhibition of the partial anodic reaction is clearly expressed.Forcitation:Menshikov I.A., Shein A.B. Protective properties of «Soling» series inhibitors in acidic media containing hydrogen sulphide. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 7. P. 90-97

Synthetic studies on the molybdenum cofactor: Total synthesis of pterindithiolenes by direct dithiolene formation from suitable pterin alkynes

ABSTRACTA novel, efficient total synthesis of a series of pterindithiolenes (15, 16, 17 and 18) [(5,6-dihydro-[1,4]dithiin or 6,7-dihydro-5H-[1,4]dithiepin systems respectively for six and seven membered dithiolenes] has been reported. The six membered quinoxaline thioketal 9 and seven membered quinoxaline dithiolene 11 have also been synthesized from quinoxaline acetylenic alcohol 5 and the corresponding acetylenic ketone 10 respectively. The synthesis of five membered pterin thioketals 12 and 13 along with the conversion of 13 to the dithiolene 14 by the reaction with NBS is also reported.

Comparative reactivity of hydroxyketones and their derivatives in the reactions with N,S-nucleophiles

The reactions of thiosemicarbazide (TSC), thiocarbohydrazide, and hydrazine thiocarbamate with oxyketones, haloketones, and derivatives of acetylenic alcohols were studied. Thiadiazines bearing exocyclic thio and hydrazo groups were synthesized. Acetylenic alcohols react with TSC to give the corresponding thiazolidines. The reactions of halo derivatives of acetylenic alcohols with TSC are complicated by side reactions.

The influence of the organolithium reagent nature on the possibility of the O→Csp migration of the R3Si group in propynes HC≡CCH2OSiR3

A possibility of the O→Csp 1,4-migration of the R3Si group in silyl ethers of terminal acetylenic alcohols upon treatment with organolithium reagents (RLi) was studied. In the case of 3-trimethylsilyloxypropyne, depending on the nature of RLi, the heterolysis of the Si—O bond occurs either by the action of acetylide formed as a result of deprotonation with the formation of 3-trimethylsilylprop-2-yn-1-ol trimethylsilyl ether, or by the action of the metalation agent with the formation of propargyl alcohol. The realization of the O→Csp 1,4-migration of the Me3Si group requires the use of mild organolithium reagents (lithium hexamethyldisilazanide and diisopropylamide). Silyl ethers having steric hindrance at the carbon atom bonded to the reaction center or around the silicon atom do not react with the studied organolithium reagents.

The Synthesis of Phenyl Acetylene Phenols for Development of New Explosives

The purpose of this research is to produce derivatives of simple phenols as “raw material” for the synthesis of new phenolic explosives. A big number of valuable products is synthesized from phenol and its homologues including well-known explosives - picric acid, methyl picrate, cresolite, etc. In general, a structural modification of well-known explosives’ molecules is the most important among the methods for the synthesis of new explosives. This method can be used in certain modifications. For example, the synthesis of methyl picrate is possible not only to replace picric acid’s hydroxyl with metoxyl, but with nitration of anisole as well, i. e, by the reciprocating synthesis. Thus, to produce the new analogues of well-known phenolic explosives, the preliminary modification of simple phenols’ molecules and further nitration, presumably by a formation of dinitro derivatives may be performed. The alkylation of phenol, anisole and m – cresol by the secondary phenyl acetylene alcohols in the presence of concentrated phosphoric acid was carried out. Para-substituted alkynyl phenols with high yields were developed. The chemical transformations were carried out by a participation of their molecules’ active centres. The corresponding ethers, esters and saturated isologues have been synthesized. The article describes the conditions of a synthesis of 14 new phenyl acetylenes’ substances that may be used as substrates in a nitration reaction.