摘要:
p-Hydroxyphenylacetic acid is prepared by reduction of p-hydroxymandelic acid with HI in the presence of red phosphorus. According to a preferred embodiment, the reaction is carried out in one vessel in which the mandelic acid is prepared in situ from phenol and glyoxylic acid.
摘要:
Phenylacetic acid and the simple derivatives thereof are prepared by catalytic hydrogenation of mandelic acid and its appropriate derivatives in the presence of a noble metal catalyst in aqueous solution which is free from mineral acid, especially free from hydrochloric acid.
摘要:
Ketones are prepared by reacting carboxylic acid halides, in particular carboxylic acid chlorides, with aluminum-alkyl compounds, optionally in the presence of an aluminum trihalide, in methylene chloride as the solvent, at a temperature between about 20.degree. and about 100.degree. C., preferably between about 30.degree. and about 60.degree. C., more preferably of about 40.degree. C. which is the reflux temperature of the methylene chloride. When operating at a temperature above approximately 40.degree. C., pressure higher than atmospheric is applied. The reaction mixture is worked up in usual manner, suitably by decomposition with water followed by distillation.
摘要:
Disclosed are stabilized aqueous polymer compositions containing A) a stabilizing amount of a least a sulfur dye or containing a stabilizing amount of a sulfur dye with a compound comprising a heterocyclic system containing nitrogen and sulphur as ring heteroatoms and B) at least one polymer comprising groups which are capable of complex formation with ions. The aqueous polymer compositions are stabilized against thermal or other degradation processes of the polymer by addition of component A) to allow their use even under harsh conditions.
摘要:
In a brake-force splitting gear for a manually actuated parking-brake system in a motor vehicle, brake force is transmitted via cable assemblies both to a wheel brake or shaft brake on the vehicle transmission and to wheel brakes of at least one driven vehicle axle. The wheel brakes of each vehicle axle being articulated in each case via a differential element mounted in a housing or frame. The splitting gear includes a lever mechanism comprising at least two balance beams or levers which split the brake force between the transmission brake and wheel brakes.
摘要:
Disclosed are stabilized aqueous polymer compositions containing A) a stabilizing amount of a least a sulfur dye or containing a stabilizing amount of a sulfur dye with a compound comprising a heterocyclic system containing nitrogen and sulphur as ring heteroatoms and B) at least one polymer comprising groups which are capable of complex formation with ions. The aqueous polymer compositions are stabilized against thermal or other degradation processes of the polymer by addition of component A) to allow their use even under harsh conditions.
摘要:
In an arrangement for transferring brake torques of a vehicle drive line including a differential transmission having a housing, a driving pinion and two wheel shafts supported in the housing and a brake structure arranged adjacent the housing, a brake member is provided for rotation with the driving pinion and a braking member is supported by the housing of the differential transmission for engaging the brake member when the brake structure is actuated.
摘要:
For producing coupling members with a negative relief of the load-bearing contact surfaces, according to a method for the precision forging of coupling members, it is proposed that in a rough-forging process, first of all contact surfaces (5) parallel to the direction of the forging stroke are produced and in particular with an admeasurement exceeding the adjoining top faces (2) at least in the marginal region adjoining the respective common edge (3) of the spacers and that in a subsequent cold gauging process, the top faces are forged with exact measurements so that every finished contact surface extends obliquely towards the top face enlarged by gauging.
摘要:
A service brake for a vehicle, having two brake circuits which can be acted upon by pressurized fluid by way of a vacuum brake booster and a dual brake master cylinder, has at least one switchable device for changing the hydraulic pressure intensification by which, in the event of a failure of the brake booster, the pressure of the brake fluid is increased in each of the two brake circuits.
摘要:
A braking force distribution linkage for a muscular energy-actuated parking brake system of a motor vehicle, in which the braking force is transferred at least via control cables both to one gear of the vehicle's transmission and to the wheels of at least one driven vehicle axle, the wheel brakes on each vehicle axle being respectively articulated via a compensation element. A linkage, lever and balance arm arrangement ensures a sufficient parking-hold effect on a road surface with differing nonskid properties, even in the event of failure of a portion of the braking system.