Preservative systems on the basis of cationic surfactants are known i n the art, a typical example of such cationic surfactants is the ethyl ester of the lauramide of arginine monohydrochloride ( LAE ) (2). Besides the chloride form the corresponding bromide and sulphate salts are known. It was found that other salts of the cationic surfactants display excellent properties, such as the salts oflactic acid, glutamic acid and acetic acid. It was further found that the combination of the cationic surfactants with at least one salt of an organic or inorganic acid displayed an excellent preservative action. A further preservative system with favourable properties was the combination of the cationic surfactants with at least one ester compound, amide or enzyme inhibitor. Also the combination of the cationic surfactant with a further cationic molecule such as ethyl arginate, glucosamine or chitosan led to an effective preservative system. A further effective preservative system turned out to be the cationic surfactant in encapsulated form.

Preservative systems comprising cationic surfactants

The discovery of vitamins as essential factors in the diet was a scientific breakthrough that changed the world. Diseases such as scurvy, rickets, beriberi, and pellagra were recognized to be curable with an adequate diet. These diseases had been prevalent for thousands of years and had a dramatic impact on societies as well as on economic development. This Review highlights the key achievements in the development of industrial processes for the manufacture of eight of the 13 vitamins.

One Hundred Years of Vitamins—A Success Story of the Natural Sciences

The design and fabrication of chiral nanostructures is a promising approach to realize enantiomeric recognition and separation. In our work, gold nanorod@chiral mesoporous silica core–shell nanoparticles (GNR@CMS NPs) have been successfully synthesized. This novel material exhibits strong and tunable circular dichroism signals in the visible and near-infrared regions due to the optical coupling between the CMS shells and the GNR cores. When chiral cysteine molecules are loaded in the porous shells, the corresponding surface enhanced Raman scattering spectroscopy demonstrates a distinct chiral recognition effect, which can be used to semiquantitatively measure the composition of chiral enantiomers. A detailed sensing mechanism has been disclosed by density functional theory calculations.

Gold nanorod@chiral mesoporous silica core-shell nanoparticles with unique optical properties.

The use of isocyanides in heterocyclic synthesis. a review

Amino acid-based surfactants – do they deserve more attention?

Long chain N-acylglutamic acid was prepared in a high yield by a reaction of glutamic acid with fatty acid chloride in a mixed solvent of water and a water miscible organic solvent such as acetone, methyl ethyl ketone, dioxane, tetrahydrofuran,t-butyl alcohol or cyclohexanone. In this reaction the composition of the mixed solvent influenced the yield of N-acylated glutamic acid and the best yield was obtained when the reaction was carried out in the mixed solvent comprising 30–60% v/v of the organic solvent. Long chain N-acylaspartic acid was also obtained in a high yield by the same method. As the other method to obtain N-lauroyl-D L-glutamic acid, it was examined that N-acyl-α-aminoglutarodinitrile which was obtained by a reaction of α-aminoglutarodinitrile with fatty acid chloride was hydrolyzed with an aqueous alkaline solution. The salts of long chain N-acylglutamic acid are known as the surface active agents that react mildly on the human skin.

Surface active N-acylglutamate: I. Preparation of long chain N-acylglutamic acid

The physicochemical properties of long chain N-acylglutamic acids (AGA) and their sodium salts (AGSn) are described. The solubility, Krafft point, pH value, critical micelle concentration, surface tension and foaming power were measured. The properties of the optically active AGA or AGSn differed from those of the corresponding racemates, especially in solubility. The monosodium salts generally had high Krafft points, but monosodium N-oleoylglutamate had a low Krafft point. The monosodium salts hydrolyzed in the diluted aqueous solution to liberate the AGA. The aqueous solutions of the monosodium salts had low surface tensions and good foaming properties. The disodium salts were highly soluble in water, while surface tensions and foaming properties were inferior to those of the corresponding monosodium salts.

Surface active N-acylglutamate: II. Physicochemical properties of long chain N-acylglutamic acids and their sodium salts

The Synthetic Intermediate of Pyridoxine. I. A Novel Synthesis of 5-Alkoxy-2-carboxy-4-methyloxazole

A mixed acid anhydride consisting of higher fatty acid having 6 to 22 carbon atoms and sulfuric anhydride is reacted with amino acids, peptides or proteins in the presence of a base to form N-higher aliphatic acyl derivatives of amino acids, peptides or proteins respectively in good yield. The reaction mixture comprises N-acylated-amino acids, peptides or -proteins and sulfate salts and may be directly used as detergent.

Process for preparing N-higher aliphatic acyl derivatives of amino acids, peptides or proteins

THE ENZYMES PRESENT IN AN ENZYME-BEARING DETERGENT COMPOSITION ARE STABILIZED BY SMALL AMOUNTS OF N-ACYL AMINO ACIDS WHOSE ACYL GROUPS ARE DERIVED FROM SATURATED OR UNSATURATED FATTY ACIDS HAVING 6 TO 20 CARBON ATOMS, AND THE ENZYMES ARE ALSO STABLE IN DETERGENTS IN WHICH THE N-ACYL AMINO ACIDS ARE THE PRIMARY SURFACTANT INGREDIENTS.

Ryonosuke Yoshida

Papers

Surface active N-acylglutamate: I. Preparation of long chain N-acylglutamic acid

Surface active N-acylglutamate: II. Physicochemical properties of long chain N-acylglutamic acids and their sodium salts

The Synthetic Intermediate of Pyridoxine. I. A Novel Synthesis of 5-Alkoxy-2-carboxy-4-methyloxazole

Process for preparing N-higher aliphatic acyl derivatives of amino acids, peptides or proteins

Enzyme-containing detergent composition