摘要:
The invention relates to a method for the oxidation of a primary or secondary alcohol, preferably to form an aldehyde or ketone, comprising the following steps: a) providing a catalyst composition comprising at least one compound containing a nitroxyl radical, at least one NO source, at least one carbon or mineral acid or an anhydride of a carbon or mineral acid; b) producing a reaction mixture by adding at least one primary or secondary alcohol and a gas comprising oxygen and optionally one or more than one solvent to the catalyst composition from step a) or step e); c) incubating the reaction mixture from step b) at a temperature of between 0 and 100° C. or at the boiling point of the solvent; d) simultaneously with or subsequent to step c): crystallizing the reaction product; and e) recovering the catalyst composition by removing the crystallized reaction product from the reaction mixture obtained in step d).
摘要:
The invention relates to a method for producing 2,6-dioxabicyclo-(3.3.0)-octane-4,8-dione (I), comprising the oxidation of dianhydrohexitols (II-IV), or of corresponding hydroxy ketones, with an oxygen-containing gas in the presence of a catalyst composition, the reaction proceeding without the addition of halogen sources.
摘要:
The invention relates to a method for producing 2,6-dioxabicyclo-(3.3.0)-octane-4,8-dione (I), comprising the oxidation of dianhydrohexitols (II-IV), or of corresponding hydroxy ketones, with an oxygen-containing gas in the presence of a catalyst composition, the reaction proceeding without the addition of halogen sources.
摘要:
Circuit arrangement for stabilising the speed of a d.c. motor which is controlled via a control amplifier, and drives a tacho-meter which is connected between the bases of a "long-tailed pair," a tuned circuit being included between the collectors which is tuned to the tacho frequency and which attenuates the other frequencies, the voltage across the tuned circuit being applied to the control amplifier via a charge pump.
摘要:
The invention relates to a method for the oxidation of a primary or secondary alcohol, preferably to form an aldehyde or ketone, comprising the following steps: a) providing a catalyst composition comprising at least one compound containing a nitroxyl radical, at least one NO source, at least one carbon or mineral acid or an anhydride of a carbon or mineral acid; b) producing a reaction mixture by adding at least one primary or secondary alcohol and a gas comprising oxygen and optionally one or more than one solvent to the catalyst composition from step a) or step e); c) incubating the reaction mixture from step b) at a temperature of between 0 and 100° C. or at the boiling point of the solvent; d) simultaneously with or subsequent to step c): crystallizing the reaction product; and e) recovering the catalyst composition by removing the crystallized reaction product from the reaction mixture obtained in step d).
摘要:
An illumination system and method for illuminating an output patch includes a first array for receiving light, and which includes first lenslets. A second array, which includes second lenslets, receives the light from the first array and outputs the light to the illumination patch. The first lenslets have a uniform shape and the second lenslets have a non-uniform shape thereby reducing optical extent and maximizing system lighting efficiency.
摘要:
An arrangement for focussing an image of an information structure which is disposed on or in a substantially flat record carrier, light being projected onto the light-sensitive detector via an optical element and a record carrier, which detector via a control system controls the optical element, the control system also receiving a signal which is a measure of the velocity of movement, which signal limits said velocity of movement.
摘要:
A device for writing information in a disk-shaped record carrier, and/or for reproducing the recorded information, the transducer being radially movable relative to the record carrier, which transducer is disposed on a tubular member, which at its one end is provided with a drive coil and at its other end with a tachometer coil, which coils are movable in an air gap of a stationary magnet system.
摘要:
The invention relates to a method for producing aldehydes and ketones from easily accessible primary and secondary alcohols by oxidation with atmospheric oxygen or pure oxygen using a catalyst system which consists of a derivative of a free nitroxyl radical.
摘要:
An apparatus for reading a disc-shaped record carrier on which information is stored in a preferably spiral-shaped track. Said information is read optically with the aid of a radiation beam, which via a directing system transfers the information contained in the scanning point of the record carrier to a read detector. The radial position of the scanning point is controlled with the aid of a control system which via a first pattern of radiation spots which is projected onto the record carrier receives information about said radial position and by means thereof controls the directing system. In order to ensure that the system is stable under all conditions use is made of a second pattern of radiation spots which are projected onto the record carrier, which pattern is radially shifted relative to the first pattern, and from which a control signal is derived with which the transfer function of the control system is varied so as to stabilize the control system.