摘要:
A process and apparatus for producing a laminate containing a metal foil strip and a plastic film strip, in which the two strips have stamped structures repeated at regular intervals in the longitudinal direction of the strips and are disposed at contiguous points in the laminate, a pre-stamped strip and the second strip being continuously joined together from one end. To laminate stamped plastic film tape together with a pre-stamped metal foil tape, with the least possible complexity, so that any mismatch between the stamped structures of the two tapes is as small as possible, after the strips have been merged, the position of position markings for the stamped structures in the second strip and on the pre-stamped strip are successively scanned and, once a predetermined position of the position markings has been reached, a stamped structure is introduced into that region of the second strip situated in front of the site of the joining together, at a distance from the predetermined position corresponding to an integral multiple of the interval at which the stamped structures of the pre-stamped metal strip are repeated.
摘要:
A process for the preparation of tetrahydrofuran or tetrahydrofuran and .gamma.-butyrolactone from the product of the hydrogenation of maleic acid, succinic acid, maleic anhydride, succinic anhydride and/or fumaric acid, by treating the crude hydrogenation product, without prior work-up, at from 100.degree. to 300.degree. C. with a protic acid, and isolating pure tetrahydrofuran and .gamma.-butyrolactone from the resultant reaction mixture by distillation.
摘要:
Sugar ketals are prepared by reacting a sugar with a ketone in the presence of an acid catalyst by a process in whichA. a molecular boron trifluoride compound or trifluoromethanesulfonic acid is used in an amount of only from 0.01 to 10% by weight, based on the sugar used,B. up to a 30-fold molar excess of the ketone is used andC. the water formed during the reaction is removed continuously from the reaction mixture.In a particularly advantageous embodiment of the process, the boron trifluoride is used in the form of boron trifluoride etherate and, when the reaction is complete, this compound or the trifluoromethanesulfonic acid is rendered ineffective under non-aqueous conditions, after which the ketone is evaporated off and the reaction mixture is then subjected to fractional distillation. The process is particularly important for the reaction of L-sorbose with acetone to obtain 2,3:4,6-di-O-isopropylidene-L-sorbofuranose, which is required for the synthesis of ascorbic acid.
摘要:
Finely divided, pulverulent carotinoid or retinoid compositions, in which the carotinoid or retinoid essentially has a particle size of less than 0.5 micron, are prepared by a process wherein a carotinoid or retinoid is dissolved in a volatile, water-miscible, organic solvent at from 50.degree. C. to 200.degree. C., if necessary under superatmospheric pressure, within the space of less than 10 seconds. The carotinoid is immediately precipitated, in a colloidally disperse form, from the molecularly disperse solution by rapidly mixing the latter with an aqueous solution of a swellable colloid at from 0.degree. C. to 50.degree. C., and the resulting dispersion is freed from the solvent and the dispersing medium in a conventional manner.
摘要:
It is the purpose and object of the present invention to make better use of the emission range of light sources and to create the diazonium salts necessary for such purpose. The diazonium salts of the present invention of the general formula ##STR1## wherein Y is ##STR2## R.sub.1, R.sub.2 are equal or different and are, alkyl having 1 to 10 carbon atoms, aryl having 6 to 10 carbon atoms in a mono or polycylic ring;R.sub.3 is hydrogen, halogen, alkyl, alkoxy, cyano;R.sub.4 is hydrogen, halogen, alkyl, alkoxy; andX.sup.e is an anion,can be employed with all known couplers and additives in diazotype materials. They have an absorption range of 480 to 550 nm.
摘要:
A process for separating off organic iodine compounds from acetaldehyde-free carbonylation products of methanol, methyl acetate and dimethyl ether by removing the iodine compounds by azeotropic distillation with a hydrocarbon having a boiling point, under atmospheric pressure, of 25-55.degree. C.