Salts Of Strong Acids Research Articles

Halide-catalyzed cis product formation in the hydrolysis of anti-benzo[a]pyrene diol epoxide and its alkylation of poly(A).

The carcinogen 7-r,8-t-dihydroxy-9-t,10-t-epoxy-7,8,9,10- tetrahydrobenzo[a]pyrene (anti-BPDE) forms diastereomeric cis and trans products in its reactions with nucleic acids and water (adducts and tetrols, respectively). The effects of salts, buffers, and DNA on the hydrolysis product ratio were tested. Halide ions increase the cis-tetrol/trans-tetrol ratio, with the order of effectiveness being I > Br > Cl >> F. No cation effect was apparent. Non-halide salts of strong acids increase the ratio to a small degree. Buffers decrease the ratio, with phosphate being more effective than cacodylate. DNA also reduces the ratio, with denatured DNA being more potent than native DNA. Halide ions appear to catalyze cis-tetrol formation via trans halohydrin intermediates. At the lowest halide concentrations which significantly raise the product ratio, and at all levels of chloride ion, the rate of anti-BPDE hydrolysis is not greatly increased, indicating that the halide ions are reacting primarily with the BPDE carbocation formed in the rate-determining step. At higher concentrations, iodide ion and, to a lesser degree, bromide ion significantly accelerate hydrolysis, indicating that BPDE undergoes SN2 attack by these ions. Chloride ion was also found to increase the proportion of cis adducts formed between anti-BPDE and poly(A). The cis adduct/trans adduct ratio was quadrupled by 0.5 M NaCl. This suggests that chlorohydrins can be intermediates in the alkylation of nucleic acids by epoxides of polycyclic aromatic hydrocarbons.

Mixed-dimer formation between dimeric lithium 2,6-dimethylphenolate and the lithium salts of strong acids

The 13 C, 7 Li, and 6 Li NMR spectra of lithium 2,6-dimethyl-, 4-bromo-2,6-dimethyl-, and 2,4,6-tribromophenolates in 1,3-dioxolane and THF and in the presence of LiClO 4 , LiBPh 4 , LiCl, and lithium p-toluenesulfonate are reported for a wide range of temperature and concentration. It is established that all systems give rise to mixed dimers. The extent of mixed-dimer formation is shown to depend on the basicity of the phenolate ion, the cation solvation power of the solvent, and the nature of the anion

A complex binder based on active silica gel for aluminosilicate gunite bodies

In order to prepare gunite bodies of aluminosilicate composition, we developed complex binders formed due to the combined addition of liquid glass and a coagulant in the form of aqueous solutions of the salts of strong acids. The application of the complex binders facilitates separation of active silica gel directly on the surface of the refractory particles composing the gunite coating and, thereby, ensures rapid setting of the coating, its high strength, and reduces the losses due to bounce during guniting operation.

Rapid and efficient preparation of free amino acids from strong acid salts on columns of crosslinked poly-4-vinylpyridine

Acidic and neutral amino acids were recovered from their strong acid salts or from large excesses of strong acids by passage through columns of crosslinked poly-4-vinylpyridine. Basic amino acids eluted as the monoacid salts. High recoveries were possible with submicromolar samples.

A preparative and 1H and 13C NMR spectroscopic study of mercury(II)-Arene complexes

A wide range of new arene complexes of mercury(II) have been isolated from the appropriate arene and a strong acid salt of mercury (Hg(SbF 6) 2, HgF(AsF 6) or Hg(O 2CCF 3) 2) in liquid SO 2. Low-temperature, slow-exchange (except when Arene = C 6H 6), 1H and 13C NMR spectra of the systems Hg(SbF 6) 2AreneSO 2 have provided evidence for very stable Hg(Arene) 2+ and Hg(Arene)2 2+ complexes. Intramolecular exchange is rapid at the lowest accessible temperatures: the intramolecular exchange-averaged couplings to 199Hg suggest strongly that the arenes are bound to mercury in an η 1-manner.

π-Arene complexes of the main group elements. II. Complexes of cadmium(II) and zinc(II)

π-Arene complexes of cadmium(II) and zinc(II) have been prepared from the first time. The 1:1 complexes Cd(AsF 6) 2. Arene(Arene=hexaethylor hexamethylbenzene, pentamethylbenzene, durene, p -xylene or benzene), Cd(SbF 6) 2. Arene(Arene = hexamethylbenzene, toluene or benzene) and Zn(SbF 6) 2. Arene(Arene = hexamethylbenzene or pentamethylbenzene) are synthesized from the strong acid salt and arene in liquid sulfur dioxide. 1H and 13C NMR spectra are consistent with localized bonding of the arene to the metal cation. Exchange-averaged vn] 13C chemical shifts for the systems Cd(AsF 6) 2-arene-SO 2 confirm the 1:1 stoichiometry in solution and suggest that the stabilities of the complexes are in the approximate range 0.48 – 2.1 M −1 for the series benzene-hexamethylbenzene. For the system Cd(AsF 6) 2-C 6Me 6-SO 2, a detailed 113Cd NMR study is consistent with the solution stoichiometry and stability determined from 13C NMR. In general, complexation to an arene produces deshielding of the 113Cd resonance of Cd(AsF 6) 2.

Purification and Characterization of RNA Polymerase from Fremyella diplosiphon

We have purified and characterized a DNA-dependent RNA polymerase from the blue-green alga Fremyella diplosiphon. This enzyme, purified by gel filtration, DEAE-cellulose chromatography, and glycerol gradient centrifugation, is comprised of five polypeptide subunits. Their masses are 161,000, 134,000, 91,000, 72,000, and 41,000 daltons. Preparative electrophoresis of the purified enzyme on nondenaturing gels separates the 41,000-dalton polypeptide from the rest of the enzyme. The enzyme is extremely labile in the presence of a variety of salts of strong acids and bases; the purification procedure was devised to avoid exposure to such compounds.

Swelling and contraction of heart mitochondria suspended in ammonium phosphate.

Bovine heart mitochondria which have been allowed to swell in isotonic NH4+ phosphate contract in response to initiation of oxidative phosphorylation. The contraction occurs optimally at pH 6.0 and appears from inhibition studies to result from Pi uptake being slower than removal of internal Pi via phosphorylation of external ADP. Similar results are obtained when K+ + nigericin is substituted for NH4+. Mersalyl inhibition of Pi transport in respiring, nonphosphorylating mitochondria which have been allowed to swell in NH4+ phosphate reveals a contractile process having an alkaline pH optimum. This contraction resembles closely the contraction observed in salts of strong acids and presumably occurs by electrophoretic ejection of Pi anions driven by electrogenic H+ ejection.

New examples of the metal basicity of iron pentacarbonyl

Fe(CO)5, though a weak base, forms adducts with strong acid salts including Cd(AsF6)2, Sn(SbF6)2, and Fe(SbF6)2; in the adducts, the Fe(CO)5 behaves as a weak Fe-donor ligand to the metal cation.

Abspaltung säurelabiler Aminoschutzgruppen durch Pyridiniumsalze / The Removal of Acid-labile Amino-protecting Groups by Pyridinum Salts

Pyridinium salts of strong acids are usefull reagents in organic solvents, e. g. methanol, for the selective cleavage of acid labile amino-protecting groups as the trityl, o-nitrophenylsulfenyl, and the 2-(ρ-biphenyl)-isopropyloxycarbonyl residue. The cleavage reactions are investigated with respect to time, temperature, concentration of the reagent, different solvents, different pyridinium salts with and without addition of indole, and sterically hindrance by the structure of the amino acids.

クロムメッキ液中のSO<sub>4</sub>の自動制御

The self-regulation of sulfate concentration by the addition of Sr2+ to a chromium plating bath saturated with SrSO4 was studied. The following results were obtained: (1) Since SrSO4 is a strong acid salt, the solubility of SrSO4 in low pH solution such as a chromium plating bath was not much higher than that in its aqueous solution. (2) The SO4 concentration could freely be regulated by the addition of SrCO3 to the chromium plating bath. (3) The decrease in the solubility of SrCO3 conformed to “common-ion effect” in the chromium plating bath, but not in the aqueous solution. It would be more clear by assuming activity instead of concentration. Namely, the ionic strength was higher and steady in the chromium plating bath and was supposed to be proportional to CrO3 concentration; but it was changeable in the aqueous solution. (4) For example, the solubility of SrSO4 (as SO4) was 1.4g/l in chromium plating bath containing 50g/l of CrO3 at 55°C. When SrCO3 of 6.0g/l was added to the bath, the SO4 concentration became 0.5g/l, by which the plating bath for self-regulating SO4 was prepared.

クロムメッキ液中のSiF<sub>6</sub>の自動制御

The self-regulation of fluorosilicate concentration by the addition of K+ to a chromium plating bath saturated with K2SiF6 was studied. The following results were obtained: (1) Since K2SiF6 is a strong acid salt, the solubility of K2SiF6 in low pH solution such as a chromium plating bath was not much higher than that in its aqueous solution. (2) The decrease in the solubility of K2SiF6 conforming to “common-ion effect” did not agree to the following dissociation. K2-SiF6→2K++SiF62-. (3) The reason was explained by the following hydrolysis of K2SiF6: K2SiF6+H2O→2K++SiF5(OH)2-+HF. The dissociation of a fluorosilicate having higher solubility such as Na2Si F6 was as follows: Na2SiF6→2Na++SiF62-. Whereas, the dissociation of a fluorosilicate having lower solubility such as BaSiF6 was as follows: BaSiF6+2H2O→Ba2++SiF4(OH)22-+2HF. The results of experiments well agreed with the basis of these dissociations. (4) For example, the solubility of K2SiF6 was 10g/l in chromium plating bath containing 250g/l of CrO3 at 55°C. Therefore, the plating bath for selfregulating SiF6 was prepared by the addition of a small amount of K2CO3 to the bath. The solubility of K2SiF6 was 7g/l in low concentration chromium plating bath containing 50g/l of CrO3 at 55°C. Since the optimum concentration of K2SiF6 in this bath is 0.6g/l, 27.5g/l of K2CO3 shall be added to get the self-regulating bath. However, this composition was not adequate for the chromium plating bath owing to the increase of pH value.

Separation of uin‐ and multivalent cations and selective de‐ionisation by a phosphonic cation exchanger

AbstractThe phosphonic cation exchanger in its free acid form is able to remove multivalent cations even from neutral and medium acidic solutions of salts of strong acids completely, and is regenerated by a stoichiometric amount of a regenerating agent. It is therefore possible to separate multivalent cations from univalent cations in a simple way by means of a phosphonic cation exchanger, followed by a weakly basic anion exchange resin. This results in a selective or partial de‐ionisation of solutions with an eventual recovery of multivalent cations using an economical regeneration dosage and with a minimum of waste.

Swelling and contraction of heart mitochondria suspended in ammonium chloride.

Bovine heart mitochondria which have been allowed to swell in isotonic NH 4 + phosphate contract in response to initiation of oxidative phosphorylation. The contraction occurs optimally at pH 6.0 and appears from inhibition studies to result from Pi uptake being slower than removal of internal Pi via phosphorylation of external ADP. Similar results are obtained when K+ + nigericin is substituted for NH 4 + . Mersalyl inhibition of Pi transport in respiring, nonphosphorylating mitochondria which have been allowed to swell in NH 4 + phosphate reveals a contractile process having an alkaline pH optimum. This contraction resembles closely the contraction observed in salts of strong acids and presumably occurs by electrophoretic ejection of Pi anions driven by electrogenic H+ ejection.

Helix–random chain transitions of polyamino acids in organic acid–salt solutions

AbstractPolyamino acids which are soluble and helical in acetic acid and dichloroacetic acid (DCA) have been observed to undergo a helix to random chain transition upon the addition of lithium salts of strong acids. The transition can be reversed by diluting the salt. Apparently only lithium cations are able to bring about the polycarbobenzoxy‐L‐lysine (PCBL) transition in acetic acid, whereas the anions display a varying degree of effectiveness; ClO4− > Br− > TSA− > Cl− > NO3−. The lithium salts of carboxylate anions such as OAc− and TFA− do not cause polymer unwinding in acetic acid. Neither do the acids, TSA, HCl, TFA, or DCA induce the transformation in acetic acid. Poly‐L‐alanine (PLA) in DCA unfolds as LiBr is added, but does not unfold in the presence of 0.5M (CH3)4NBr, 0.25M CsBr, or 0.32M HCl. These results are explained on the basis of a direct interaction of the lithium salt with the polymer amide groups to form an ion‐pair complex. The extent to which the union of the ion pair can dissociate from the complex in the low dielectric constant, environment determines the degree of unfolding of the polymer. The anion dissociation equilibrium presumably therefore would lie in the same order as given above. Acids such as HCl and TSA are considered to substantially protonate and ion‐pair with the polymer, but do not readily dissociate the anion partner from the complex, and therefore do not produce an unstable positively charged helical structure.

867. The hydrolysis of carboxylic anhydrides. Part II. The effects of salts of strong acids on the hydrolysis of acetic anhydride

867. The hydrolysis of carboxylic anhydrides. Part II. The effects of salts of strong acids on the hydrolysis of acetic anhydride

A non‐hydrolytic polymerization of ϵ‐caprolactam. The polymerization initiated by hydrogen chloride

AbstractSome experiments are described which show that the polymerization of ϵ‐caprolactam (CL) can be accomplished by heating the lactam under anhydrous conditions in the presence of hydrogen chloride or of salts of strong acids and ammonia or amines at temperatures of 220–260°C. To study this type of polymerization more closely, two series of kinetic experiments with the sytem CL–HCl hae been performed (254°C.; initial molar ratios of HCl to CL, 0.025 and 0.0125). The progress of the reaction, characterized by the degree of conversion (determined by extraction of the unconverted lactam with water), is compared with the polymerization of CL initiated by corresponding amounts of water or of ϵ‐aminocaproic acid. The products obtained have been characterized by endgroup titration values and intrinsic viscosity. Some additional data have been obtained by chromatography and IR investigations. The titrations show that the molecules bear an amino group at one end of the chain; the nature of the other endgroup is still obscure. Reaction constants calculated for an uncatalyzed additon of CL to amino groups prove to be of about the same magnitude as those of the water‐initiated polymerization without additional HCl. At the same time some kinetic experiments with the system CLH2OHCl are presented. Both systems have some striking features in common. The catalytic effect of the HCl present in this system can be attributed to the rapid formation of amino groups in the very first moments of the reaction, thus leading to an enhanced rate of polymerization by addition of CL to amino groups.

Apparent Free Space

The difficult problems associated with the entry of dissolved substances into plant cells have been made more difficult by failure to envisage the prop­ erties which must be attributed to the cells in order to account for their known behaviour in a wide range of treatments. It is generally accepted that there is, between the vacuole and the outside of a plant cell, a barrier or bar­ riers which offer a high resistance to the passage of many solutes including salts of strong acids and bases. The tonoplast which separates the vacuole from the cytoplasm is accepted as one such barrier, but many assume that there is also another barrier at the outside of the cytoplasm adjoining the cell wall. Although we believe that no such barrier exists for many solutes we do not propose to consider all the evidence in detail, nor is it the purpose of this article to survey the history of what we believe to be erroneous concepts. It might, however, be pointed out that while some investigators [e.g., Arisz (1)] have not subscribed to the widely accepted view, others [e.g., Lundegardh (15)] have described the surface of the root cell as a membrane of oriented lipoid molecules adjoining the cell wall and resistant to the entry of dissolved substances. Recently Lundegardh (16) has come to the conclusion that the evidence for a necessitates the abandonment of this earlier hy­ pothesis. Little has been published on the concept of and noth­ ing has been published on the complementary concept of osmotic volume, terms which have long been in use in Cambridge. Since there has been some misunderstanding of these terms and their significance, it is de­ sirable that they should be examined in some detail. Since only the outlines can be given in an article of this type, a more detailed treatment of the con­ cept setting out the basis for many of the estimations given in this paper will be published elsewhere [Briggs (4)]. In 1948, Briggs & Robertson (6) pointed out that the tissue in which the intercellular spaces have been filled with water behaves as if the movement of larger molecules (e.g., sugar) and of electrolytes were restricted mainly to the around the vacuoles; this was discussed as the phase in the tissue in which solutes move relatively freely and from which they are removed into the vacuoles. This the free space, cannot be measured unless its properties relative to the meas­ uring system are known. We can therefore get only estimates of its dimen­ sions. For these estimates, the term apparent space was proposed by

The inhibition of hatching of potato root eelworm (Heterodera rostochiensis Woll.) in partially sterilized soil.

Experiments on the hatching of Heterodera rostochiensis have shown that the addition of ammonium carbonate to potato root water markedly inhibits hatching when the concentration of ammonia introduced is approximately 100 p.p.m. The strong acid salts of ammonia in equivalent amounts have no such inhibitory effect.These observations are linked with experiments on the effect of partial sterilization of soil on the hatching of H. rostochiensis, and it is demonstrated that delay of hatching in such soils is only effective so long as the ammonia concentration within the soil is maintained at a sufficiently high level.

Physicochemical investigation of a cation exchange resin (amberlite IR100) I. Resin equilibria

1. 1. Equilibria between a sulfonic acid resin (Amberlite IR100) and salts of strong and weak acids are investigated. The limiting exchange (at high concentrations) is nearly the same for all alkali and alkaline earth chlorides and sulfates at low pH. It is greater for salts of weak acids, at higher pH, and increases in the order of decreasing acid dissociation constant. This suggests that the resin contains groups which are more weakly acid than -S0 3H, probably -COOH and phenolic -OH. The limiting exchange at pH = 2.0–2.5 is a few per cent below the strong acid equivalent as characterized by the sulfur content and the potentiometric titration curves. 2. 2. The law of mass action is applied to resin equilibria with salts of strong acids. The ratio of activity coefficients of the hydrogen ion to that of metal ion in the resin phase shows a marked variation with the experimental conditions. A number of possible causes for this is discussed.