摘要:
Process for preparing glyoxylic esters or their hydrates in which a water-soluble salt of a maleic or fumaric monoester or a mixture thereof is reacted with ozone in aqueous solution at temperatures of from 0 to 50.degree. C., and the corresponding glyoxylic ester or its hydrate is isolated from the resulting reaction mixture.
摘要:
Process for the purification of o-phthalaldehyde in which an alcoholic solution containing the crude, unpurified o-phthalaldehyde is adjusted to a pH between 0 and 3 at a temperature between 0.degree. and 60.degree. C., then an alkaline solution is added, and the corresponding dialkoxyphthalan is extracted from the organic phase and purified by distillation and, when required, converted into the purified o-phthalaldehyde by hydrolysis.
摘要:
Process for the preparation of alpha, omega-alkanedicarboxylic acids of the general formula I ##STR1## in which A is an alkylene radical having 4-14 C atoms by reacting a cycloalkene of the general formula II ##STR2## in which A has the abovementioned meaning with ozone in the presence of an inert solvent, catalytically hydrogenating the peroxide solution formed, followed by oxidation of the dialdehyde formed to the diacid of the formula I in the presence of an inert aprotic solvent.
摘要:
Process for the preparation of pure 2,3-pyridinedicarboxylic acids of the formula I which are substituted in position 4 and/or 5 and/or 6 by R1, where R1 is hydrogen, C1-C4 alkyl, C1-C4 alkoxy, C1-C4 alkoxy-C1-C4 alkyl, halogen, hydroxyl or nitro, from quinolines of the formula II in which R1 is as defined above, and which are substituted in position 6 and/or 7 by R2, where R2 is hydrogen, C1-C4 alkyl, C1-C4 alkoxy, C1-C4 alkoxy-C1-C4 alkyl, halogen, hydroxyl, nitro or amino, which are reacted in the first step in aqueous sulfuric acid or nitric acid solution with ozone in the ratio of from 1:2 to 1:3 at temperatures from 0 to +50° C., and the resulting peroxide solution is then reacted at temperatures of from +0 to +100° C. in the presence of 0.5-4.0 mol of oxidizing agent per mole of ozonolysis product formed, after which the pH of the reaction solution is adjusted to 0.2 to 3, the mixture is cooled to 0 to 30° C., and the precipitated pyridinedicarboxylic acid is isolated.
摘要:
Improved, safe process for the purification of ketones obtained by ozonolysis and subsequent reduction of the corresponding terpenes, in which, after the ozonolysis and reduction of acyclic mono-, bi- or tricyclic terpenes with ozonizable double bonds, converting the resulting corresponding crude ketone into a high-purity ketone by means of steam distillation at atmospheric pressure or at reduced pressure, extraction of the steam distillate and subsequent distillation.
摘要:
A relay is formed by a magnet system containing a wound coil body, an L-shaped core arranged axially therein, an L-shaped armature and a base element with terminal elements. Stationary and moving contact elements are arranged between the base element and the magnet system. The armature is mounted with the free end of its transverse leg at the free end of the longitudinal leg of the core. The armature is secured through a U-shaped armature spring wrapping around the armature. The spring is secured with one arm at the longitudinal leg of the armature and a second arm is inserted in a recess between the coil body and the core. The actuation of the moving contact elements is provided via a slide coupled to the armature. This slide is hooked to the armature by spring tabs of the armature spring at opposing sides of the armature through snap latches formed at the ends of the side arms of the slide.
摘要:
Apparatus is provided for determining the topography, thickness, and fiber orientation of the nerve fiber layer at the fundus of the eye by measuring the polarization shift induced in a return beam of polarized light which is reflected at the ocular fundus from an incident beam of a known polarization state. A corneal polarization compensator effectively cancels the birefringent effects of the cornea and other portions of the eye anterior to the fundus, so that clinically meaningful results are produced.
摘要:
Means and Method are provided for determining both the topography and the thickness of the nerve fiber layer at the fundus of the eye by measuring the polarization shift of the reflected probing light. The technique is greatly enhanced in the accuracy of its results by the utilization of a corneal polarization compensator, which lies at the heart of the invention.
摘要:
Improved process for preparing high-purity, halogen-free o-phthalaldehyde, in which a) tetrahalo-o-xylene is hydrolyzed at a temperature of 155-160° C. and a pressure of from 2 to 5 bar, where appropriate in the presence of a phase-transfer catalyst, to o-phthalaldehyde, which b) is converted in an acidic alcoholic solution at a temperature of from 0 to the reflux temperature into the corresponding dialkoxyphthalane and, subsequently, c) an acetal cleavage is effected by acid hydrolysis at a pH >1.5 to pH 7, resulting in high-purity, halogen-free o-phthalaldehyde.