Dry HCl Gas Research Articles

NiII, PdII and PtII pincer complexes of 2-(diphenylphosphanyl)-N-(2-(diphenyl-phosphanyl)benzyl)benzamide: synthesis, reactivity and catalytic studies.

In this article, the synthesis of bis(phosphine), o-Ph2PC6H4C(O)N(H)CH2C6H4PPh2-o (1) (hereafter referred to as "PCNHCP" and its anionic form as "PCNCP") and its group 10 metal chemistry and catalytic studies are described. PCNHCP (1) on reaction with NiCl2(DME) and PdCl2(COD) afforded pincer complexes, [MCl{(PCNCP)κ3-P,N,P}] (M = Ni, 2; Pd, 3). A similar reaction of 1 with PtCl2(COD) yielded a chelate complex, [PtCl2{(PCNHCP)κ2-P,P}] (4), which on further treatment with LiHMDS produced the 1,2-azaphospholene-phosphine complex, [PtCl(Ph){(o-P(Ph)C6H4CONCH2C6H4PPh2-o)κ2-P,P}] (5) via P-C/P-N bond metathesis. Passing dry HCl gas through the solution of 5 resulted in benzene elimination to form [PtCl2{(o-P(Ph)C6H4CONCH2C6H4PPh2-o)κ2-P,P}] (6). Treatment of 1 with PtCl2(COD) and Pt(Cl)(Me)(COD) in the presence of a base resulted in pincer complexes [PtX{(PCNCP)κ3-P,N,P}] (X = Cl, 7; Me, 8). Nickel complex 2 catalyzed the Suzuki-Miyaura cross coupling reaction between bromobenzene and phenyl boronic acid to give the corresponding biphenyls in good yield. The platinum complex 5 showed good catalytic activity towards regio- and stereoselective hydroboration of terminal alkynes. Both the catalytic reactions were performed under mild reaction conditions with a very low catalyst loading.

Process integration of hydrolysis and hydrogen generation processes in the six-step Cu-Cl cycle for green hydrogen production

The ICT-OEC six-step Cu-Cl cycle dissociates water thermochemically to produce hydrogen and oxygen. In the Cu-Cl cycle integrating the hydrolysis and hydrogen processes poses a crucial engineering challenge. Hydrolysis at 350-400 °C requires extra steam, resulting in the generation of dilute HCl instead of dry HCl gas, which must be recycled for hydrogen production. To address this, pressure swing distillation (PSD) is integrated into the hydrolysis and hydrogen generation reactions to separate HCl and water. The study examines operating parameters in PSD processes. A simulated process integration model includes an intermediate heat recovery steam generator (HRSG) with PSD to complete the overall conceptual design. The nuclear-based Cu-Cl cycle without PSD demonstrates a lower environmental impact when compared to the Cu-Cl cycle with PSD. The Cu-Cl cycle with a higher HCl concentration in PSD feed exhibits a minimum global warming potential (GWP) value of 2.53 kg of CO2 eq for 1 kmol/h hydrogen production.

Platinum Assisted Tandem P-C Bond Cleavage and P-N Bond Formation in Amide Functionalized Bisphosphine o-Ph2PC6H4C(O)N(H)C6H4PPh2-o: Synthesis, Mechanistic, and Catalytic Studies.

The reactions of amide functionalized bisphosphine o-Ph2PC6H4C(O)N(H)C6H4PPh2-o (1) with platinum salts are described. Treatment of 1 with [Pt(COD)Cl2] yielded a chelate complex, [PtCl2{o-Ph2PC6H4C(O)N(H)C6H4PPh2-o}κ2-P,P] (2), which on subsequent treatment with LiHMDS formed a novel 1,2-azaphospholene-phosphine complex [Pt(C6H5)Cl{o-C6H4{C(O)N(o-PPh2(C6H4))P(Ph)}}κ2-P,P] (3) involving a tandem P-C bond cleavage and P-N bond formation. The same complex 3 on passing dry HCl gas afforded the dichloro complex [PtCl2{o-C6H4{C(O)N(o-PPh2(C6H4))P(Ph)}}κ2-P,P] (5). Complex 2 upon refluxing in toluene or treatment of 1 with [Pt(COD)Cl2] in the presence of a base at room temperature resulted in the pincer complex [PtCl{o-Ph2PC6H4C(O)N(C6H4PPh2-o)}κ3-P,N,P] (4). Reaction of 1 with [Pt(COD)ClMe] at room temperature also afforded the pincer complex [PtMe{o-Ph2PC6H4C(O)N(C6H4PPh2-o)}κ3-P,N,P] (6). Mechanistic studies on 1,2-azaphospholene formation showed the reductive elimination of LiCl to form a phosphonium salt that readily adds one of the P-C bonds oxidatively to the in situ generated Pt0 species to form a chelate complex 3. The analogous palladium complex [PdCl2{o-C6H4{C(O)N(o-PPh2(C6H4))P(Ph)}}κ2-P,P] (7) showed excellent catalytic activity toward N-alkylation of amines with alcohols with a very low catalyst loading (0.05 mol %), and the methodology is very efficient toward the gram-scale synthesis of many N-alkylated amines.

Antimicrobial Evaluation and Efficient Green Synthesis of 8-Substituted-2,5-dihydro-1,5-benzothiazepine Derivatives

8-Substituted-2,5-dihydro-1,5-benzothiazepine derivatives have been synthesized by the reaction of 1-(2-furyl)-3-(3,4-dimethoxyphenyl)-2-propenone with six 5-substiuted-2-minobenzenethiols in dry ethanol saturated with dry HCl gas and also in the presence of aluminium nitrate as catalyst in dry ethanol. All the newly synthesized compounds were characterized by analytical and spectral data comprising IR, 1H NMR, 13C NMR, 19F NMR and mass studies. All these compounds have also been evaluated for their antimicrobial assay against the Gram-positive bacteria, Staphylococcus aureus and the Gram-negative bacteria, Pseudomonas aeruginosa and the fungus, Candida albicans. The antifungal activity was found to be more significant than antibacterial activity.

Recycling of rare earth elements from FeNdB-Magnets via solid-state chlorination

Recycling of rare earths from magnetic alloys such as Fe14Nd2B is a widely studied field of research. However, with rare earth metal prices falling, leaching of magnet materials with mineral acids has become economically unfeasible. In order to circumvent high expenditures, solid-state chlorination offers an attractive alternative. Chlorination takes place via partial decomposition of NH4Cl at temperatures between 225 and 325 °C. Subsequently, dry HCl gas reacts with the magnet material in a rotary kiln to form water-soluble metal chlorides, which are dissolved in an acetic acid buffer medium. Here, spent Fe14Nd2B-magnets from a wind turbine served as starting material. For the first time, the solid-state chlorination process was optimised with the aid of statistical experimental design considering binary factor correlations. The global optimum was determined by varying the amount of NH4Cl, temperature, residence time and buffer mass in the subsequent leaching step. The maximum rare earth yield amounted to 84.1%. For dissolving rare earths quantitatively, the unreacted residue requires recirculation. In this respect, solid-state chlorination was compared to an optimised state-of-the-art process employing hydrochloric acid for digestion. The solid-state chlorination process was found to be superior in that consumption of chemicals was reduced by 45%, no costs for neutralisation incur and chemical costs were decreased by at least 51%.

The Use of Pinner Type Reaction for the Synthesis of New Indeno[2,1‐c]pyridine‐4‐carbonitrile Derivatives

An efficient and convenient route was developed for the synthesis of new pyridinecarbonitrile derivatives by using the Pinner type of reaction. The 2‐((E)‐2‐((dimethylamino)methylene)‐1,2‐dihydro‐5,6‐dimethoxyinden‐3‐ylidene) malononitrile 2 was reacted in the presence of dry HCl gas to yield 3‐chloro‐6,7‐dimethoxy‐9H‐indeno[2,1‐c]pyridine‐4‐carbonitrile (3) in good yield. The SNAr reaction on compound 3 with various nucleophiles yielded 3‐substituted pyridinecarbonitriles 4, 5, 6, 7, 8, 9 in moderate to good yield.

Controlled C-5 Chlorination and Dichlorohydrin Formation of Uracil Ring with HCl/DMF/Oxone��System

showed similar trends (entries 3-6). Thecorresponding 5-chloro derivatives 2c and 2d were obtainedin good yields (82-90%) and dichlorohydrin derivatives 3cand 3d were obtained in good yields (83-84%). 5-Substitut-ed uracil derivatives, 1e and 1f, produced the correspondingchlorohydrins 3e and 3f (entries 7 and 8). The relatively lowyield of 3f might be due to the presence of a large 5-bromosubstituent in 1f. The 5-bromination and dibromohydrinformation of 1b were carried out with 48% aqueous HBrsolution in DMF (entries 9 and 10). The yield of 5-bromo-1,3-dimethyluracil (2e) was reasonable (62%) while theyield of dibromohydrin 3g was low (41%) due to a similarsteric reason as in the case of 3f. When we used aqueousHCl (37%) instead of dry HCl gas, the yield of 2b decreasedto 51% (rt, 2 h, 1.5 equiv of KHSO

Syntheses of 1,5-Benzothiazepines: Part XXXVI—Syntheses and Antimicrobial Evaluation of 2-(2-Chlorophenyl)-4-(4-chlorophenyl/2-thienyl)-2,5-dihydro-8-substituted-1,5-benzothiazepines

Six 5-substituted-2-aminobenzenethiols have been reacted with 3-(2-chlorophenyl)-1-(4-chlorophenyl)-2-propenone and 3-(2-chlorophenyl)-1-(2-thienyl)-2-propenone in dry ethanol saturated with dry HCl gas, to obtain twelve new compounds, 8-substituted-2-(2-chlorophenyl)-4-(4-chlorophenyl/2-thienyl)-2,5-dihydro-1,5-benzothiazepines in satisfactory yields. The structures of the final products have been assigned by elemental microanalyses data for elements, C, H, and N and by IR, 1 H NMR, and mass spectroscopies. The synthesized compounds have been evaluated for their relative antimicrobial activity against the gram-positive bacteria, Staphylococcus aureus, gram-negative bacteria, Pseudomonas aeruginosa and the fungus, Candida albicans. The compounds have been found to show little antibacterial activity, but interestingly, showed significant antifungal activity.

Acidichromism and Supramolecular Chirality of Tetrakis(4-sulfonatophenyl)porphyrin in Organized Molecular Films

An anionic porphyrin, tetrakis(4-sulfonatophenyl)porphyrin (TPPS), was assembled into complex organized molecular films with an l-glutamic acid derivative (l-GluC18) or octadecylamine (ODA) through in situ complex formation at the air/water interface. TPPS could form J-aggregates when deposited from the pH 3.1 subphase or exist as H-dimers from the pH 5.1 subphase. The complex films showed acidichromism (i.e., reversible color changes upon alternate exposure to acidic and basic gases). Despite the initial color, the film turned into a wheat color, and TPPS aggregated into an H-dimer when exposed to ammonia gas. When treated with dry HCl gas, the film became light yellow, and the H-dimer changed into the protonated species. Upon subsequent exposure to water vapor, the film became yellow, and TPPS formed a J-aggregate in the film. Three states including the H-dimers, protonated species, and J-aggregates in the films could be switched by exposing the film to NH3, dry HCl, and subsequently water vapor, respec...

A conducting composite based on poly(N-vinylcarbazole)–formalin resin and acetylene black

A poly(N-vinylcarbazole) (PNVC)–formalin (FO) resin (PNVC-FO) was prepared via copolycondensation between N-vinylcarbazole (NVC) and FO in the presence of dry HCl gas in toluene medium at 110°C. A highly conducting composite of PNVC-FO resin with nanodimensional acetylene black (AB) was prepared by carrying out the polycondensation reaction in presence of a suspension of acetylene black (AB) in toluene. The inclusion of PNVC in the PNVC-FO-AB composite was confirmed by FT-IR analysis. Scanning electron microscopic analyses of PNVC-FO resin and PNVC-FO-AB composite revealed formation of spherical particles and aggregates of irregular shapes respectively. Thermogravimetric analyses revealed the overall stability order as: AB > PNVC-FO-AB composite > PNVC-FO resin > PNVC homopolymer. In sharp contrast to PNVC and PNVC-FO resin, which were both nonconducting (10−12 to 10−16 S/cm), the conductivity of the composites reached values between 0.75 S/cm and 6.54 S/cm corresponding to AB loading of 28–49 wt % respectively. Temperature versus conductivity studies revealed an initial increase in conductivity upto 200°C and current–voltage characteristics of the PNVC-FO-AB composite showed a linear trend consistent with Ohmic behavior. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3837–3843, 2007

Design, synthesis and pharmacological screening of a series of N1-(substituted)aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)pyrimidin-4(3H)-ones as potential histamine H1-receptor antagonists

A series of N1-(substituted)aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)pyrimidin-4(3H)-one was designed on the basis of the triangular pharmacophoric requirement of histamine H1-receptor antagonists. The designed series was synthesized by cyclo-condensation of monoaryl thiourea with ethyl cyanoacetate in the presence of dry HCl gas to give N1-(substituted aryl)-2-mercaptopyrimidine-4(3H)-one, which on cyclo-condensation with acetylacetone gave the pyridopyrimidinone. Further methylation of the mercapto group at C-2 with methyl iodide followed by nucleophilic displacement of the methylmercapto group by various amines gave the targeted compounds. All the synthesized compounds were screened for histamine H1-receptor antagonistic activity by the in vitro method of inhibition of the isotonic contraction induced by histamine on isolated guinea pig ileum using cetirizine as a standard drug. All the compounds exhibited potent histamine H1-receptor antagonistic activity with pA2 values from 7.30– 9.75 (cetirizine, pA2 value 9.40). The potent compounds were screened for their in vivo antihistaminic activity by protection of animal from asphyxic shock. The sedative potential of potent compounds was checked on albino mice by photoactometer and they had comparative sedative potential to the standard drug cetirizine. None of the compound exhibited anticholinergic activity in the in vitro rat ileum model.

An Efficient Strategy for the Synthesis of 1-Chloroethyl Phosphates and Phosphoramidates

[reaction: see text] A versatile, efficient, and simple method for the preparation of various 1-chloroethyl phosphates and phosphoramidates is described. The protected chlorophosphates or phosphoramidates are synthesized to the vinyl derivative under mild conditions, followed by conversion to the chloroethylidene phosphate or phosphoramidate by dry HCl gas, resulting in good to excellent yields. 1-Chloroethyl phosphates and phosphoramidates are excellent building blocks for the synthesis of novel ethylidene-linked phosphate prodrugs.

Thermal dehydration of lanthanum chloride heptahydrate: thermodynamic approach

Production of rare-earth metals from molten chloride electrolysis demands the use of anhydrous chloride in order to increase current efficiency. The main difficulty in obtaining these chlorides is due to oxychloride formation. Any thin film of the oxychloride or oxide will tend to inhibit the reduction process. The main purpose of this work was to develop an operational diagram related to the dehydration of lanthanum chloride heptahydrate. This diagram agrees with previous experimental data which have shown that dehydration of light rare-earth chlorides can be effective at relatively low temperatures in a dry HCl gas atmosphere.

A Gas Chromatographic Method for the Sugar Analysis of 3,6-Anhydrogalactose-Containing Algal Galactans

This paper describes a new gas chromatographic method for the compositional analysis of algal galactans containing 3,6-anhydrogalactose, which is readily destroyed in usual acid hydrolysis and methanolysis. Mercaptolysis of galactans was carried out under an anhydrous condition using the newly developed solvent system, an ethanethiolic HCl solution which had been prepared by blowing dry HCl gas into ethanethiol. By heating galactans in 0.5 N HCl/ethanethiol at 60°C for 12 h, component sugars including 3,6-anhydrogalactose were released quantitatively as their diethyl mercaptals. The monosaccharide diethyl mercaptals were trimethylsilylated and analyzed by gas–liquid chromatography. Each component monosaccharide was detected as a single peak since neither anomeric nor structural isomers can be produced by mercaptolysis. Furthermore, the solvent system was improved by the addition of methanol in a ratio (2/1, v/v) of ethanethiol to methanol. Heating of galactans at 60°C in 0.5 N HCl/[ethanethiol:methanol (2/1, v/v)] released more rapidly and quantitatively monosaccharide diethyl mercaptals without any formation of monosaccharide methyl glycosides. The present method was applicable to not only algal galactans but also algal powders.

A Convenient Synthesis of 2′- OR 4′-Hydroxycocaine

: A short, convenient and efficient synthesis of 2′- or 4′-hydroxycocaine is described. The key step involved selective hydrolysis/transesterification of the acetoxy group of 2′- or 4′-acetoxycocaine in methanol saturated with dry HCl gas.

Synthesis and ligand binding studies of 4'-iodobenzoyl esters of tropanes and piperidines at the dopamine transporter.

Four analogs and two homologs of cocaine, designed as potent cocaine antagonists, were synthesized. The SN2 reaction between ecgonine methyl ester (13) or appropriately substituted piperidinol (19, 21) and appropriately substituted 4-iodobenzoyl chloride gave 4-iodobenzoyl esters of tropanes and piperidines (5-8). 2'-Hydroxycocaine (9) was obtained from 2'-acetoxycocaine (12) by selective transesterification with MeOH saturated with dry HCl gas. 2'-Acetoxycocaine (12) was synthesized from acetylsalicyloyl chloride (23) and ecgonine methyl ester (13). The binding affinities of these compounds were determined at the dopamine transporter for the displacement of [3H]WIN-35428. An iodo group substitution at the 4'-position of cocaine decreased dopamine transporter binding potency, while a hydroxy or acetoxy group at the 2'-position exhibited increased binding potency for the dopamine transporter compared to cocaine (10- and 3.58-fold, respectively). 2'-Hydroxylation also enhanced the bidning potency of 4'-iodococaine (5) by 10-fold. Replacement of the tropane ring with piperidine led to poor binding affinities.

Closed-cycle HCl/H 2/Cl 2 energy storage and power generation system using a [formula omitted] catalyst

An energy storage system based on HCl-H 2-Cl 2 chemistry is described. When dry HCl gas is passed over a copper surface, H 2 is released and Cu is oxidized to CuCl. Subsequently, upon heating to high temperatures, the CuCl bed is decomposed back to Cu, releasing Cl 2. The release of H 2 from HCl on a Cu surface was studied as a function of temperature, flow rate, and specific surface area. The products H 2 and CuCl were measured between 400 and 600 K; temperature has only a small effect on the reaction rate, at most T 1 2 . The surface geometry and gas flow allowed several thousand gas-surface collisions per HCl molecule for complete conversion of HCl to H 2. The thickness of the CuCl layer is not the limiting factor in the reaction probability for layers less than a few thousand monolayers deep. Recovery of Cl 2 by the thermal decomposition of CuCl was examined as a function of temperature and pressure. Useful Cl 2 yields were found only for system pressures below ca. 10 torr, at temperatures above 700 K, and using a flow of inert gas to sweep out the product.

SYNTHESIS OF N-(4-2H-1-BENZOPYRAN-2-ONE-2-THIAZOLYL)PHTHALIMIDES

Abstract 3-(ω-Bromoacetyl)coumarins I, on reaction with potassium thiocyanate in absolute alcohol, gave 3-thiocyanato acetyl coumarins II. Treatment of II with dry HCl gas in chloroform afforded 3-(2-chlorothiazol-4-yl)-2H-1-benzopyran-2-ones III. Condensation of III with phthalimides resulted in the formation of N-(4-2H-1-benzopyran-2-one-2-thiazolyl)phthalimides IV, respectively.

Optochemical HCl Gas Detection Based on Tetraphenylporphine Dispersed in Ethyl Cellulose

Abstract To detect sub-ppm levels of dry HCl gas, spectral changes of tetraphenylporphine dispersed in ethylcellulose were examined in the visible region. The Soret and Q-bands of free base tetraphenylporphine are sensitive to sub-ppm levels of HCl with a good reversibility and insensitive to NH3, Cl2, NO2 and NO at room temperature.

New Synthesis of 1,4 Benzodiazepine-2,5-diones by Means of HCL Gas Catalyst

Abstract A new synthesis of 1,4- benzodiazepinediones 4 , particularly 1,4-dihydro1H-1,4-benzodiazepine-2,5-dione, 4c key intermediate of metabolites cyclopenin 9 , cyclopenol 10 , cyclopeptine 11 and dehydrocyclopeptine 12 , was achieved by action of dry HCl gas in DMF on compound 3 prepared from anthranilic acid derivative 1 and amino ester 2 .