Über die Adsorption von Fettsäuren an Ionenaustauschern

Adsorption of Fatty Acids on Ion Exchangers The author examined the adsorption of saturated fatty acids C₁₀ to C₁₈ on strong- and weak-basic anion exchangers in the presence of n-hexane, acetone and 96% ethanol. The extent of adsorption on dried anion exchangers is small, and in nonpolar solvents, the effective capacity amounts to 5% of the theoretical capacity. With wetted resins, not the polarity of the solvents but the dissociation of the functional groups of the exchanger is the factor determining adsorption. Since the adsorbing ability of the exchanger is limited by the length of the fatty acid molecules, the effective capacity of strongly basic exchangers amounts only to one-third or a half of the theoretical capacity.     

Zur Konstitution der Reaktionsprodukte aus Phenacylthioglykolsäure und Benzylmercaptan sowie aus Phenacylbenzylsulfid und Thioglykolsäure

On the Structure of the Reaction Products from Phenacyl Thioglycolic Acid and Benzyl Mercaptan and from Phenacyl Benzyl Sulfide and Thioglycolic Acid Phenacyl benzyl sulfide gives with thioglycolic acid the expected mercaptol C₆H₅C(SCH₂COOH)₂CH₂SCH₂C₆H₅ ( 5 ) as the only reaction product, while phenacyl thioglycolic acid and benzyl mercaptan give the mercaptol C₆H₅C(SCH₂C₆H₅)₂CH₂SCH₂COOH ( 6 ) as well as the mercaptal C₆H₅CH(SCH₂C₆H₅)Ch(SCH₂C₆H₅)₂ ( 4 ). The reactions took place in presence of hydrochloric acid. On the basis of the synthetic and the n.m.r. spectroscopic studies the reaction mechanisms are discussed.     

Cyansäureester. 35. Über Bildung und Folgereaktionen von N-Cyanatophthalimid. Neue spezifisch aktivierte und blockierte Isatosäurederivate

Cyanic Acid Esters. 35. On Formation and Consecutive Reactions of N-Cyanato Phthalimide. New Specifically Activated and Blocked Isatoic Acid Derivatives Depending on the reaction conditions N-hydroxy-phthalimide affords on treatment with cyanogen bromide via N-cyanato phthalimide 2 the iminocarbonate 3 and isatoic acid derivatives 7 and 16 . Both the latter react with nucleophiles as isatoic acid derivatives activated on the carboxylic group and protected on the carbamic group or vice versa, furnishing N,N-bis alkoxycarbonyl anthranilic acid amides 9 , N-alkoxycarbonyl anthranilic acid amides 12 , o-alkoxycarbonyl phenyl ureas 17 and the benzotriazepin-2,5-dione 14 . The structures of the new compounds are proved by ¹H-n.m.r. and ¹³C-n.m.r. measurements as well as independent synthesis.     

Darstellung und 1H-NMR-spektroskopische Untersuchung von β-substituierten Äthylen-phenylphosphinsäure-äthylestern

Preparation and ¹H N.M.R. Spectroscopic Investigation of β-Substituted Ethyl Esters of Ethylene-phenylphosphinic Acid The ethyl ester 3 of diphenylphosphorylmethyl-phenyl-phosphinic acid in benzene reacts regiospecifically and stereoselectively with aldehydes, in presence of sodium hydride, to 2-substituted ethyl esters of trans-ethylene-1-phenylphosphinic acid 8 (E-isomers) in satisfactory yields. The ABX type H-n.m.r. spectra of isolated pure products 8 were analysed. The trans configuration of these compounds is characterized by the specific signal sequence of ethylene proton H_B.     

Synthese und Komplexchemische Eigenschaften eines neuen Chelon-Mikrosphären-Dextrangels

The covalent anchoring of chelating groups on a spherical dextran gel by the simultaneous action of alkali dextran, 2,3-dibrompropionic acid, and iminodiacetic acid under various conditions was investigated. The formation of stable metalchelate complexes of the resulting spherical polymer is demonstrated by means of neutralization curves for bivalent metallic ions with the succession of selectivity corresponding with the course for N-donator atoms. The presence of functional α,β-alanine-N,N-diacetic acid groups and weakly acidic carboxylic groups is inferred from the different stabilities and capacities in dependence on pH for In³⁺, Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Mn²⁺, Mg²⁺, Ca²⁺, in comparison with the N-content on spherical dextran derivate capacity of a competing ligand in solution.     

DNA adsorption on poly(N,N‐dimethylacrylamide)‐grafted chitosan hydrogels

In this study, poly(N,N‐dimethylacrylamide) grafted chitosan (PDMAAm‐g‐CT) hydrogels were prepared for deoxyribonucleic acid (DNA) adsorption. Instead of directly grafting the N,N‐dimethylacrylamide (DMAAm) monomer onto the chitosan (CT) chains, poly(N,N‐dimethylacrylamide) with carboxylic acid end group (PDMAAm‐COOH) was firstly synthesized by free‐radical polymerization using mercaptoacetic acid (MAAc) as the chain‐transfer agent and then grafted onto the CT having amino groups. The synthesis of PDMAAm‐COOH and its grafting onto the CT chains were confirmed by attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy. From gel permeation chromatography measurements, the number‐average molecular weight (M _n) and polydispersity index of PDMAAm‐COOH were found as 2400 g/mol and 2.3, respectively. The PDMAAm‐g‐CT hydrogels were utilized as the adsorbents in DNA adsorption experiments conducted at +4°C in a trisEDTA solution of pH 7.4. The hydrogels produced with higher PDMAAm‐COOH content exhibited higher DNA adsorption capacity. The DNA adsorption capacity up to 4620 μg DNA/g dry gel could be achieved with the PDMAAm‐g‐CT hydrogels prepared in 80.0 wt % PDMAAm‐COOH feed concentration. This value is approximately seven times higher than that of CT alone. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Grafting onto wool. XXVIII. Effects of acids on gamma-radiation induced graft copolymerization of ethylmethacrylate onto wool fiber

Graft copolymerization of ethylmethacrylate (EMA) onto Himachali wool fiber has been investigated in aqueous medium by mutual gamma irradiation from a Co⁶⁰ source in air and in nitrogen atmosphere. Percentage of grafting has been evaluated as a function of (i) total dose, (ii) concentration of monomer, and (iii) effect of concentration of different acids such as hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, and acetic acid. Maximum percentage of grafting has been obtained in the presence of sulfuric acid. Following reactivity order of different acids towards grafting has been observed: H₂SO₄ > HCI > HNO₃ > HCIO₄ > CH₃COOH. A plausible mechanism to explain the effect of acids on percentage of grafting of EMA has been suggested.     

Zur Acylierbarkeit des Phosphorylsauerstoffs. I. Acyloxyphosphoniumsalze aus Hexamethylphosphorsäuretriamid und Carbonsäurederivaten

On the Acylation of the Phosphoryl Oxygen. I. Acyloxyphosphonium Salts from HMPT and Carboxylic Acid Derivates Acylation equilibria with participation of acyloxyphosphonium ions exist in solutions of HMPT and carboxylic chlorides, or anhydrides, respectively, as can be shown by ³¹P-n.m.r. after trapping the counter ion with SbCl₅. Moderately stable acyloxyphosphonium salts have been isolated for the first time by acylation of HMPT. In the alternative reaction of (Me₂N)₃P with CCl₄ and carboxylic acids, acyloxyphosphonium salts are formed only after prolonged reaction times, due to the stability of the intermediate chlorotris-(dimethylamino)-phosphonium ion.     

Single‐Pot Ethane Carboxylation Catalyzed by New Oxorhenium(V) Complexes with N,O Ligands

The oxorhenium(V) chelates [ReOCl(N,O‐L)(PPh₃)] [N,O‐L=(OCH₂CH₂)N(CH₂CH₂OH)(CH₂COO) ( 2 ), (OCH₂CH₂)N(CH₂COO)(CH₂COOCH₃) ( 3 )] and [ReOCl₂(N,O‐L)(PPh₃)] [N,O‐L=C₅H₄N(COO‐2) ( 4 ) C₅H₃N(COOCH₃‐2)(COO‐6) ( 5 )] have been prepared by reaction of [ReOCl₃(PPh₃)₂] ( 1 ), in refluxing methanol, with N,N‐bis(2‐hydroxyethyl)glycine [bicine; N(CH₂CH₂OH)₂(CH₂COOH)], N‐(2‐hydroxyethyl)iminodiacetic acid [N(CH₂CH₂OH)(CH₂COOH)₂], picolinic acid [NC₅H₄(COOH‐2)] or 2,6‐pyridinedicarboxylic acid [NC₅H₃(COOH‐2,6)₂], respectively, with ligand esterification in the cases of 3 and 5 . All these complexes have been characterized by IR and multinuclear NMR spectroscopy, FAB⁺‐MS, elemental and X‐ray diffraction structural analyses. They act as catalysts, in a single‐pot process, for the carboxylation of ethane by CO, in the presence of potassium peroxodisulfate K₂S₂O₈, in trifluoroacetic acid (TFA), to give propionic and acetic acids, in a remarkable yield (up to ca. 30%) and under relatively mild conditions, with some advantages over the industrial processes. The picolinate complex 4 provides the most active catalyst and the carboxylation also occurs, although much less efficiently, by the TFA solvent in the absence of CO. The selectivity can be controlled by the ethane and CO pressures, propionic acid being the dominant product for pressures about ca. 7 and 4 atm, respectively (catalyst 4 ), whereas lower pressures lead mainly to acetic acid in lower yields. These reactions constitute an unprecedented use of Re complexes as catalysts in alkane functionalization.     

Synthese von Heterocyclen durch C-C-Knüpfung. II. Katalytische Cyclisierung von N-Alkyl-N-allyl-acrylamiden und N.N-Diallyl-carbonsäureamiden

Synthesis of Heterocycles by C C-Bond Formation. II. Catalytic Cyclization of N-Alkyl-N-allyl-acrylamides and N,N-Diallyl Carbonic Acid Amides N-Alkyl-N-allyl-acrylamides 2 cyclize in the presence of PdCl₂ to 1-alkyl-3,4-dimethyl-3-pyrrolin-2-ones 4 and 1-alkyl-4-methyl-3-methylene-pyrrolidin-2-ones 5 . Compounds 4 predominate in the mixture. With RhCl₃, ring closure gives comparable amounts of lactams 4 and 7 (1-alkyl-3,4-dimethyl-3-pyrrolin-2-ones) besides some product of allyl elimination. N. N-Diallyl carboxylic amides 3 form cyclic enamides (1-acyl-3,4-dimethyl-2-pyrrolines, 9 ) on the action of PdCl₂ besides the products 10 of allyl elimination. RhCl₃ effects cyclization of 3 to form 1-acyl-3-methyl-4-methylene-pyrrolidines 11 besides some 9 . The acid amide groups of compounds 9 and 11 are shown by n.m.r. spectroscopy to exist as rotamers.     

Studies on the Separation and Recovery of Palladium from Simulated High Level Liquid Waste (SHLW) Solution with Novel Extractant N,N,N′,N′-tetra (2-ethylhexyl) Dithiodiglycolamide DTDGA

The extraction properties of N,N,N',N'-tetra-(2-ethylhexyl) dithiodiglycolamide (DTDGA) have been evaluated for separation and recovery of palladium from simulated high-level liquid waste (SHLW) solution. Extraction of Pd was found to increase with increase in nitric acid concentration up to 4.0 M, above which the extraction remains almost constant. Acid uptake studies show 1:1 stoichiometry between DTDGA and HNO₃ at nitric acid concentration above 3.0 M. The acid uptake constant (K_H) was found to be 0.60 which could be due to the presence of two carbonyl groups of amidic moiety. DTDGA has shown very high extractability and selectivity for Pd over other metal ions present in SHLW. The separation factor (SF) for Pd over other metal ions was found to be more than 10⁴. Almost complete back extraction of palladium from organic phase was achieved with 0.01 M thiourea in 0.1 M nitric acid. Reusability studies of the extractant indicate that D_Pd remains almost constant even after five successive cycles of extraction and stripping. Two extraction stages will be required for complete extraction of 100 mg/L Palladium in 3.0 M nitric acid solution using 0.0025 M DTDGA/n-dodecane solvent system.     

Konformation und Rotationsbarrieren substituierter Glyoxylsäureamide

Conformation and Rotation Barriers of Substituted Glyoxylic Acid Amides Semiempirical calculations predict an orthogonal orientation of the carbonyl groups in tertiary glyoxylic acid amides, which is in good agreement with an X-ray structure analysis of 5 . Due to the influence of the α-carbonyl group, the rotation barrier in the substituted glyoxylic acid amides 2a–d, 3a, 3b , and 4–6 (ΔG^#_c = 84–92 kJ mol⁻¹) is about 10 kJ/mol higher than in simple acid amides, as was found by dynamic NMR line shape analysis.     

Kinetische Untersuchungen zum Alkylierungsvermögen von Dithiophosphorsäureestern im binären Solvensgemisch Methanol/Wasser [1, 2]

Kinetic Investigations on the Alkylation Capacity of Dithiophosphoric Acid Triesters in Binary Solvent Mixtures Methanol/Water The influence of solvent polarity on the alkylation capacity of dithiophosphoric acid triesters towards the nucleophiles trimethylamine and monomethylamine is investigated. Different binary mixtures of methanol and water and also the pure compounds are used as solvents. The observed effects are described quantitatively on the basis of Linear Free Energy Relationships by means of empirical parameters of the solvent polarity. Good results are obtained by correlation of the rate constants with the concentration of the polar component c_p by Langhals.     

Über die Konfiguration einiger durch Anlagerung von Mercaptoverbindungen an Acetylendicarbonsäure hergestellten Verbindungen

The Configuration of Some Compounds Prepared by Addition of Thiols to Acetylene Dicarboxylic Acid The acids RSC(COOH) = CHCOOH 3 with R = HOOCCH₂, HOOCCH(CH₃), C₆H₅, C₆H₅CH₂, p-ClC₆H₄CH₂ and C₆H₅CH(CH₃) have been prepared by addition of thiols RSH to acetylene dicarboxylic acid (alkali salt) in aqueous alkaline solution. It has been shown that only trans-isomers 3 and no cis-isomers 4 are formed. The methyl esters of 3 could be partially isomerized to yield the corresponding cis-esters. No cis-acids could be obtained by saponification of the latter.     

Analytik von Phosphorsäurepartialestern

Analytic of Phosphoric Acid Partial Esters Phosphoric acid partial esters are best synthesized by reaction of fatty alcohol with P₂O₅. The chosen mol ratio of fatty alcohol and P₂O₅ determines the amounts of mono-, di- and trialkylester, of oligomeric esters, of free fatty alcohol and of phosphoric acid. Several methods are used for the characterisation and determination of the individual components, the potentiometric titration, the ³¹P-nuclear magnetic resonance, the gel permeation chromatography, the ion chromatography and the supercritical fluid chromatography. The combination of all the results of the applied methods provides the key to the composition of the phosphoric acid ester. The results of the analysis are checked by a phosphorus calculation. This analytical procedure can be applied to phosphoric acid partial esters in the acid and salt form. The analysis of alkylethoxyphosphoric esters is done with the exclusion of the chromatographic methods.     

Phase behavior and structural properties for the triton X-100/<Emphasis Type="Italic">n</Emphasis>-C<Subscript>n</Subscript>H<Subscript>2n+1</Subscript>COOH/H<Subscript>2</Subscript>O system

In the Triton X-100/n-C_nH_2n+1COOH/H₂O system, n-C_nH_2n+1COOH can be used as a cosurfactant. As its chain length increases, the regions of the microemulsions showing oil-in-water (O/W), water-in-oil (W/O), and bicontinuous structures decrease and at the same time, the region of the lamellar liquid crystal increases. In the O/W region, the distribution coefficient K of n-C_nH_2n+1COOH between Triton X-100 micellar phase and water phase increases with the chain length of saturated unbranched monocarboxylic acid. The relationship between the standard solubilization Gibbs free energy of saturated unbranched monocarboxylic acid and the number of methylene groups in the saturated unbranched monocarboxylic acid is given by the equation: ΔG _m ⁰=−2.364−2.818 n(CH₂) kJ·mol⁻¹ in the Triton X-100 micellar system. In the lamellar liquid crystal region, small-angle X-ray diffraction shows that the thickness of the bilayer d ₀ is independent of the weight ratio of n-C_nH_2n+1COOH to Triton X-100, but the volume of the solvent penetrating from the solvent layer to the amphiphilic bilayer increases with the weight ratio of n-C_nH_2n+1COOH to Triton X-100. Furthermore, the d ₀ value increases with the chain length of saturated unbranched monocarboxylic acid, which will contribute to the formation and stabilization of the lamellar liquid crystal.     

α-Substituierte Phosphonate. XXII. Synthese und NMR-Spektren offenkettiger und cyclischer Acetale von Formyl-phosphonsäureestern und Formyl-diphenylphosphinoxid

α-Substituted Phosphonates. XXII. Synthesis and N.M.R. Spectra of Open-chain and Cyclic Acetals of Formyl-phosphonic Acid Esters and Formyl-diphenylphosphinoxide The synthesis of characteristical examples of open-chain and cyclic alkyl-resp. arylacetals of formyl-phosphonic acid esters and of formyl-diphenylphosphinoxide by various methods is described. The ¹H-, ¹³C- and ³¹P-n.m.r.-spectra of this compounds and their dependence on the structure is discussed.     

Surface hydrolysis of postconsumer polyethylene terephthalate to produce adsorbents for cationic contaminants

In this work, the surface hydrolysis of postconsumer polyethylene terephthalate (PET) was used to produce an ion exchange material to adsorb cationic contaminants from water. The PET surface hydrolyses were carried out in neutral, alkaline, and acid media (NaOH or HNO₃ at 7, 10, and 15 mol L^?1) under reflux producing surface carboxylic acid sites (? COOH) characterized by ATR‐IR, pyridine adsorption, titration, TG, and DSC analyses. Acid hydrolysis produced high concentrations of ? COOH (up to 0.5 mmol g^?1_PET), whereas no significant concentration of carboxylic acid sites was obtained by neutral and alkaline hydrolysis. SEM analyses suggest that the acid sites are likely located at the cracks and defects produced on the PET surface by acid hydrolysis. Neutral or alkaline hydrolysis produced a very regular and smooth PET surface with very low acid site concentrations. The adsorption isotherms of Cd⁺² as a model of heavy metal and the dye methylene blue as a model of large organic cationic molecules showed high adsorption capacities for the HNO₃‐hydrolyzed PET, whereas no adsorption takes place on the neutral‐ or alkaline‐hydrolyzed polymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5284–5291, 2006     

Reusability and selective adsorption of Pb<Superscript>2+</Superscript> on chitosan/P(2-acrylamido-2-methyl-1-propanesulfonic acid-<Emphasis Type="Italic">co</Emphasis>-acrylic acid) hydrogel

Reusability and selective adsorption toward Pb²⁺ with the coexistence of Cd²⁺, Co²⁺, Cu²⁺ and Ni²⁺ ions on chitosan/P(2-acrylamido-2-methyl-1-propanesulfonic acid-co-acrylic acid) [CS/P(AMPS-co-AA)] hydrogel, a multi-functionalized adsorbent containing –NH₂, –OH, –COOH and –SO₃H groups was studied. The CS/P(AMPS-co-AA) was prepared in aqueous solution by a simple one-step procedure using glow discharge electrolysis plasma technique. The reusability of adsorbent in HNO₃, EDTA-2Na and EDTA-4Na was investigated in detail. The competitive adsorption of the metal ions at the initial stage was compared between their equal mass concentration and equal molar concentration. In addition, the adsorption mechanism of the adsorbent for adsorption of Pb²⁺ was also analyzed by XPS. The results showed that the optimum pH of adsorption was 4.8, and time of adsorption equilibrium was about 180 min. Adsorption kinetics fitted well in the pseudo second-order model. The equilibrium adsorption capacities of Pb²⁺, Cd²⁺, Co²⁺, Cu²⁺, and Ni²⁺ at pH 4.8 were obtained as 673.3, 358.3, 176.7, 235.0 and 171.7 mg g^?1, in their given order. The adsorbent displayed an excellent reusability using 0.015 mol L^?1 EDTA-4Na solution as the eluent, and the desorption ratio could not correctly reflect the true characteristics of adsorption/desorption process. Moreover, the adsorbent showed good adsorption selectivity for Pb²⁺. The molar adsorption capacity at the initial stage with equal molar concentration was more reliable than the mass adsorption capacity during the study of selective adsorption. According to the XPS results, the adsorption of Pb²⁺ ions by the CS/P(AMPS-co-AA) absorbent could be attributed to the coordination between N atom and Pb²⁺ and ion-exchange between Na⁺ and Pb²⁺.     

Unsaturated polyesters. III. Kinetics of polyesterification of cinnamylsuccinic acid with ethylene glycol

The polyesterification reactions of cinnamylsuccinic acid with ethylene glycol in both equimolar and nonequimolar ratios were investigated over the temperature range of 130–180°C in the absence and presence of p-toluene–sulfonic acid as a catalyst. The kinetic equations were: ?d[COOH]/dt = k₁[COOH][OH]² and ?d[COOH]/dt = k₂[COOH]² for uncatalyzed and acid-catalyzed polyesterification reactions, respectively. The apparent rate constants for uncatalyzed and acid-catalyzed reactions were evaluated by using the method of least squares for various values of initial molar ratios between [OH] and [COOH]. Also, the activation parameters were calculated.