Presence Of Glycolic Acid Research Articles

Promotion of glyoxylic acid penetration into human hair by glycolic acid.

Glyoxylic acid (GA) is widely used as a straight perming agent for hair care products, however, advanced GA penetration-enhancing agents are desired due to the peculiar odour and hair colour fading caused by the continuous use of GA products. Hence, it is important to develop a penetration-enhancing agent that helps minimize the GA concentration. We have found that the combined use of GA and glycolic acid (GCA) has a strong hair straightening effect. Straightening hair test was carried out to the evaluation of the effect of additives. Liquid chromatography-mass spectrometry (LC/MS) was performed to quantify the GA penetration amount into human hair. Attenuated total reflection (ATR) Fourier transform-infrared spectroscopy (FT-IR) and FT-IR microscope were implemented to estimate the localization of GA in the hair. Straightening hair tests indicated that the hair straightening effect by GA was enhanced by the presence of GCA. LC/MS results showed that the addition of GCA enhanced the amount of GA that penetrated human hair by about four times. ATR FT-IR and FT-IR microscope measurements indicated that GA was localized more in the innermost region of hair (medulla) than the cortex and cuticle. The GA accumulated in the medulla disappeared after a hair straightener treatment at 180°C due to the chemical reaction. The GA penetration-enhancing effect of GCA is worth investigating to reduce the GA concentration in products for more comfortable use.

Weak Interactions in Cocrystals of Isoniazid with Glycolic and Mandelic Acids

This work deals with the preparation of pyridine-3-carbohydrazide (isoniazid, inh) cocrystals with two α-hydroxycarboxylic acids. The interaction of glycolic acid (H2ga) or d,l-mandelic acid (H2ma) resulted in the formation of cocrystals or salts of composition (inh)·(H2ga) (1) and [Hinh]+[Hma]–·(H2ma) (2) when reacted with isoniazid. An N′-(propan-2-ylidene)isonicotinic hydrazide hemihydrate, (pinh)·1/2(H2O) (3), was also prepared by condensation of isoniazid with acetone in the presence of glycolic acid. These prepared compounds were well characterized by elemental analysis, and spectroscopic methods, and their three-dimensional molecular structure was determined by single crystal X-ray crystallography. Hydrogen bonds involving the carboxylic acid occur consistently with the pyridine ring N atom of the isoniazid and its derivatives. The remaining hydrogen-bonding sites on the isoniazid backbone vary based on the steric influences of the derivative group. These are contrasted in each of the molecular systems. Finally, Hirshfeld surface analysis and Density-functional theory (DFT) calculations (including NCIplot and QTAIM analyses) have been performed to further characterize and rationalize the non-covalent interactions.

A study on the stereochemistry of direct conversion of polyamides to hydroxyesters using monomeric secondary chiral amines as a model compound

Stereochemistry of direct conversion of polyamides to hydroxyesters was investigated using model compounds. Optically active secondary-alkyl amines underwent the conversion to corresponding secondary alcohols in moderate yields by treatment with supercritical methanol in the presence of glycolic acid. The reaction progressed through almost completely stereochemical inversion to give secondary alcohols in high yields. Thus, the substitution reaction of the amino group to hydroxyl group progresses through SN2 type transition state accompanying with stereoinversion.

A kinetic study on the conversion of nylon 12 to methyl 12-hydroxydodecanoate in supercritical MeOH in the presence of carboxylic acid

Polyamides were effectively converted into hydroxyl esters by treatment with supercritical MeOH in the presence of glycolic acid. This transformation progressed smoothly over a period of 240 min, and the presence of glycolic acid accelerated the reaction. Kinetic analyses of the depolymerization of nylon 12 were performed by measuring the product distribution in the reaction mixture. The chemoselectivity of hydroxyl ester formation was linearly dependent on the amount of glycolic acid used. The product distribution of the reaction using pivalic acid was also measured. Simulations based on the actual time-course data enabled the estimation of kinetic parameters. The obtained kinetic parameters revealed that the rate constant for the formation of the hydroxyl ester was significantly enhanced by the presence of glycolic acid. These results clearly indicate that the monomeric unit, an amino ester, underwent a bimolecular substitution reaction with glycolic acid. Based on these results, we proposed a reaction mechanism for the formation of hydroxyl esters. Arrhenius plots of the reaction rates were used to effectively estimate the activation energy for each step.

Anisotropy in Conformation and Dynamics of a Glycolate Ion Near the Surface of a TiO2 Rutile Crystal Between Its {001} and {110} Planes: A Molecular Dynamics Study

A molecular dynamics simulation was conducted to elucidate the conformation and dynamics of a glycolate ion (CH2(OH)COO–) at the surface of a TiO2 rutile crystal. The simulation was performed for the {001} and {110} planes of the crystal. The results indicate that, for both planes, the conformation and dynamics of the ion are strongly dominated by a layered structure of water on the surface. The simulation suggests that the ion binds to the surface more stably on the {110} plane than on the {001} plane, and that the stable conformation of the ion at the surface differs between the planes: on the {110} plane the carboxyl group of the ion is preferentially oriented toward the surface, whereas on the {001} plane it is oriented toward liquid water. These simulation results are compared with the growth shapes of rutile crystals synthesized in the presence of glycolic acid, and the role of glycolate ions in controlling the morphology of rutile crystals is discussed.

Efficient depolymerization and chemical conversion of polyamide 66 to 1,6-hexanediol

Polyamide 66 was efficiently depolymerized and chemically converted by treatment with supercritical MeOH in the presence of glycolic acid. The dicarboxylic acid unit of the polymer was selectively converted to dimethyl adipate, while the diamine unit of the polymer was converted to 1,6-hexane diol via a tetramethyldiamine intermediate. The reaction in the absence of glycolic acid was sluggish, and the yields of the diester and the diol were poor. Thus, glycolic acid efficiently catalyzed the reaction to produce 1,6-hexanediol in high yield.

Effect of pH and glycolic acid on corrosion of AA6061 alloy in ethylene glycol–water solution

The corrosion behaviors of AA6061 alloy in ethylene glycol (EG)–water solution were investigated by weight‐loss test and electrochemical measurement. The surface morphology observation and composition analysis were performed by scanning electron microscopy (SEM) and energy dispersive X‐ray (EDX) spectroscopy. After weight‐loss test, the pH of EG–water solution increased. The presence of glycolic acid (GA) enhanced the corrosion susceptibility of AA6061 alloy. The higher pH value intensified the aggressive action of GA to AA6061 alloy. GA forms a complex with aluminum ions and its negative charge centers of oxygen atom plays a key role for the complex formation.

Photoactivity of brookite–rutile TiO 2 nanocrystalline mixtures obtained by heat treatment of hydrothermally prepared brookite

Pure brookite phase was prepared by hydrothermal synthesis of titanium peroxo-complex in the presence of glycolic acid at 220 °C. The structure of prepared brookite samples was determined by X-ray powder diffraction (XRD) and selected area electron diffraction (SAED). The prepared brookite was studied by in situ high temperature XRD in air. The morphology and microstructure characteristics were also obtained by transmission electron microscopy (TEM). The nitrogen adsorption–desorption was used for determination of surface area (BET) and porosity. The method of UV–vis diffuse reflectance spectroscopy was employed to estimate band-gap energies of prepared brookite. The photocatalytic activity of the prepared titania samples were assessed by photocatalytic decomposition of Orange II dye in an aqueous slurry under UV irradiation at 365 nm wavelength. The photocatalytic activity of the prepared sample brookite heated to 800 °C in air was higher than nanocrystalline unheated brookite powder.

Lactate gap and ethylene glycol poisoning

Lactate gap and ethylene glycol poisoning

Novel method for the preparation of carbon supported nano-sized amorphous ruthenium oxides for supercapacitors

Nanostructured amorphous RuO 2 · xH 2O/C composite materials are prepared via a modified sol–gel process using glycolic acid. The glycolate anion, which dissociates from glycolic acid at pH 7, behaves as a stabilizer by adsorbing onto the RuO 2 · xH 2O surface, thus resulting in particles with a size of about 2 nm. As evidenced by zeta potential measurements, the surface charge of RuO 2 · xH 2O becomes more electronegative as the amount of glycolic acid increases. After heat treatment at 160 oC to remove the stabilizer, RuO 2 · xH 2O/C is found to exhibit an amorphous structure. The specific capacitance of RuO 2 · xH 2O/C particles (40 wt% Ru) prepared in the presence of glycolic acid (0.3 g L −1) is 462 F g −1, which is 30% higher than that of the material prepared in the absence of glycolic acid. Both the nanosized particles and the amorphous structure mainly contribute to this increase in the specific capacitance.

X-ray studies on crystalline complexes involving amino acids and peptides. XXX. Structural invariance and optical resolution through interactions with an achiral molecule in the histidine complexes of glycolic acid

The crystals of DL-histidine glycolate and L-histidine glycolate were prepared and analysed as part of an ongoing programme aimed at studying biologically and evolutionarily important interaction and aggregation Patterns. Crystallization experiments involving DL-histidine and glycolic acid yielded, in addition to DL-histidine glycolate, a conglomerate containing crystals of L-histidine glycolate and D-histidine glycolate in an unusual process of chiral separation through interaction with an achiral molecule. The crystal structure of DL-histidine glycolate is made up of alternating layers of unlike molecules as in many other binary complexes involving amino acids. The structure of L-histidine glycolate involves packing of columns containing L-histidine molecules and glycolate ions tightly hydrogen bonded to one another. The arrangement is almost identical to that in the structure of L-histidine acetate, thus providing another example for the invariance of certain aggregation patterns with respect to changes in the molecules involved. The observed aggregation of molecules in the chiral complex also appears to provide a structural rationale for chiral separation of histidine in the presence of glycolic acid.

Crystal structure of tetra(glycolato)uranium(IV) dihydrate a photoreduction product of uranyl ions in the presence of glycolic acid

The crystal structure of the title compound has been determined as the first example of a monomeric carboxylatocomplex of UIV. The crystals are monoclinic, P21/a, with a= 6.555(6), b= 17.652(13), c= 8.008(2), β= 128.52(4), and Z= 2. The structure has been solved by the heavy-atom method and refined to R= 0.057 for 1 031 observed reflections. The uranium atoms are ten-co-ordinate, with bicapped square-antiprismatic geometry [U–O 2.38(2)–2.55(1)A], and the glycolate anions are planar, 1 : 4 co-ordinated.

Interaction of Mercury (II) with Organic Acids a Conductometric Study

AbstractConductometric titrations of mercury (II) perchlorate in presence of glycolic acid, hippuric acid, malonic acid and succinic acid were carried out according to JOB's method of continuous variation. A reaction mixture contained X ml of the acid and (20 – X) ml of mercury (II) perchlorate, the two components being of equal molarity. The presence of only one but well‐defined minimum in the plot of observed conductance versus X, for hippuric acid, oxalic acid, malonic acid and succinic acid showed that one complex of mercury (II) was formed in each case. The stoichiometry of the carboxylic acid complexes of mercury (II) was determined from the position of these minima and it was concluded that mercury (II) binds one hippurate, four oxalate the two malonate ions. The plot of observed conductance against X for glycolic acid, on the other hand, is characterized by the absence of any minimum and is in fact a straight line showing no interaction between mercury (II) and glycolate ion or an interaction too weak to be detectable by the presence method.Extending JOB's approach to conductometric data an attempt was made to derive quantitative expressions for the association constant of mercury (II) – carboxylic acid systems. The magnitude of association constants thus calculated showed that the carboxylic acids combined with mercury (II) with a decrease in free energy of about 5–6 kcalories/mole and that malonate is more effective than hippurate in binding mercuric ion.

The localization of alpha-hydroxy acid oxidase in renal microbodies.

AbstractThe enzymatic properties and cellular localization of α‐hydroxy acid oxidase have been studied in renal tissue of the rat. The enzyme was most active in the presence of D, L‐ α‐hydroxy valeric acid and D, L‐ α‐hydroxy butyric acid and was inactive in the presence of glycolic acid and D‐alanine. It appeared to have no co‐factor requirement. When subjected to electrophoresis in acrylamide gels, followed by cytochemical development, the enzyme was visualized as a major form accompanied by a minor component. The properties of the major electrophoretic form as determined by cytochemical reaction and densitometric scanning were similar to those determined by quantitative biochemical assay. When subjected to differential centrifugation and density equilibrium centrifugation, particles containing α‐hydroxy acid oxidase sedimented with particles containing D‐amino acid oxidase; α‐hydroxy acid oxidase, therefore, is associated with renal microbodies. The fact that α‐hydroxy acid oxidase transfers electrons to Nitro blue tetrazolium or to Tetra nitro blue tetrazolium made it possible to localize the enzyme by a light microscopic cytochemical procedure. The enzyme was found by this method to be localized predominantly in cells of the proximal tubule. It was present in particles approximately 0.5 μ to 1.0 μ in diameter mainly situated in the basal portions of these cells. These cytochemical preparations probably accurately reflect the cellular distribution of α‐hydroxy acid oxidase and, hence, of those microbodies which contain the enzyme.