Abstract:
The present invention relates to method for producing phenol which includes: a) oxidizing cumene to form an oxidation product containing cumene hydroperoxide; b) cleaving the oxidation product using an acidic catalyst to form a cleavage product containing phenol, acetone and impurities; c) neutralizing and washing the cleavage product with a basic aqueous medium to obtain a neutralized cleavage product; d) separating the neutralized cleavage product by at least one distillation step into at least a phenol containing fraction and an aqueous fraction comprising hydroxyacetone; e) treating the aqueous fraction with an oxidizing agent in presence of a base to obtain a basic aqueous medium reduced in hydroxyacetone; f) recycling at least a portion of the basic aqueous medium to the neutralizing and washing step c); and g) recovering phenol from the phenol containing fraction obtained in step d).
Abstract:
To improve energy efficiency of prior art processes while preserving the standards of quality and total yield of desired end products, a process for the preparation of phenolic compounds is proposed. The process of the invention comprises working-up of the cleavage product mixtures by distillation, which comprises resolving the cleavage product mixture into at least three fractions in a single distillation step by feeding the cleavage product mixture to the side of a distillation column, removing a first fraction comprising the ketone at the top of the distillation column, removing a second fraction comprising the phenolic compound at the bottom of the distillation column, and removing a third fraction comprising unreacted the alkylaryl compound and the hydroxy ketone, and water, as side stream, whereby the side stream take-off is situated above the feed of cleavage product mixture to the distillation column, characterized by removing heat from the distillation column, whereby the heat take-off is situated above the side stream take-off of the third fraction, and a process for separating phenol from cleavage product mixtures, wherein the cleavage product mixture prior feeding into the distillation column, is preheated to a temperature of above 70° C. at standard pressure, preferably to a temperature of above 100° C., more preferably to a temperature between 110° C. and 180° C., most preferred to a temperature of about 140° C. to 146° C., and an apparatus suitable therefore.
Abstract:
A process for the cleavage of alkylaryl hydroperoxides includes steps for producing a mixture of a concentrate that contains at least one alkylaryl hydroperoxide to be cleaved and a cleavage product obtained from the cleavage of an alkylaryl hydroperoxide, dividing this mixture into at least two parts and cleaving the alkylaryl hydroperoxides in parallel at different temperatures. One of the two parts is treated at a temperature sufficiently high for an integrated thermal post-treatment to be achieved. The process consumes less energy since less steam has to be used. Problems which can result from fouling in heat exchangers are largely prevented. No second feed point for alkylaryl hydroperoxide has to be provided. The process can be used in the preparation of phenol and acetone by the Hock method.
Abstract:
Formaldehyde-free aqueous synthetic resin dispersions are obtainable by single-stage emulsion polymerization of monomer mixtures containing (A) from 50 to 99% by weight of at least one monomer selected from the group consisting of the acrylic and methacrylic esters of C.sub.1 -C.sub.14 -alkanols, the vinyl esters of monocarboxylic acids having up to 5 carbon atoms, and styrene (monomer A), (B) from 0.5 to 40% by weight of at least one of the monomers acrylonitrile and methacrylonitrile (monomer B), (C) from 0.5 to 10% by weight of at least one monomer of the general formula I ##STR1## where R.sup.1 is hydrogen or methyl and R.sup.2 and R.sup.3 are each independently of the other hydrogen or C.sub.1 -C.sub.4 -alkyl (monomer C), (D) from 0 to 5% by weight of at least one monomer selected from the group consisting of the 3 carbon to 5 carbon .alpha.,.beta.-unsaturated mono- and dicarboxylic acids and their amides and anhydrides (monomer D), and (E) from 0 to 3% by weight of at least one further bifunctional monomer (monomer E).
Abstract:
The present invention relates to a continuous method for treating a crude phenol stream comprising methylbenzofuran and hydroxyacetone by passing the crude phenol stream through at least two reactors connected in series the reactors containing an acidic ion exchange resin, whereby the temperature in successive reactors decreases in flow direction of the phenol stream so that the temperature in the first reactor in flow direction of the phenol stream is between 100° C. and 200° C. and the temperature in the last reactor in flow direction of the phenol stream is between 50° C. and 90° C. without a thermal separation step between any of two successive reactors and to the use of this method in a process for making phenol.
Abstract:
The present invention relates to a process for preparing phenols by adding an aqueous base to the reaction product from the acid-catalyzed cleavage of alkylaryl hydroperoxides while maintaining a homogeneous phase prior to the work-up of the product.
Abstract:
In order to be able to dispense with the time-consuming and expensive manual cleaning of ship's hulls (4), a cleaning installation is proposed which consists of at least one cleaning roller (2, 3) which can be driven to rotate, is rotatably mounted in a rack (1) and whose roller structures are positioned at least partially below the surface of the water.
Abstract:
A component having a split running face for rolling elements, running face being disposed partially on a bearing cap, and a method of producing the same. According to the method, a preform is made from a material having a carbon content of at least 0.5 percent by weight; the preform is separated by fracture separation at a separation location of the preform thereby producing the bearing cap and a remainder; skin layer hardening is performed on the running face thereby producing a skin hardened layer such that the running face acquires a Rockwell hardness of 55 according to the Rockwell cone method.
Abstract:
There is described a low flammability carpet floor covering comprising a backing material, a tied-in pile yarn, and a back finish, wherein the pile yarn comprises low flammability synthetic fibers, the backing material comprises normal or low flammability synthetic fibers, and the back finish comprises a polyurethane composed of the radicals of the formulae I to VII:--CO--A1--CO-- (I)--CO--A2--CO-- (II)(--O--).sub.n --A3--(COOH).sub.m (III)--O--B1--O-- (IV)--O--B2--(O--).sub.p (V)--NH--C1--NH-- (VI)--CO--NH--D1--NH--CO-- (VII)where the proportions of the radicals I to III, based on their total amount, are within the following limits:I: 40 to 80 mol %,II: 10 to 40 mol %,III: 0 to 25 mol %,the proportions of the radicals IV, V and VI, based on their total amount, are within the following limits:IV: 65 to 95 mol %,V: 0 to 19 mol %,VI: 3 to 16 mol %,the radicals of the formulae I, II and IV are polyester blocks having an average molecular weight of from 400 to 6000 and the proportions of the radicals of the formula VII, based on the total amount of all the components of the polyurethane resin, are from 5 to 35 mol %, preferably from 10 to 25 mol %, and a process for producing the low flammability carpet floor covering.There is further described an aqueous composition comprising this polyurethane resin and the use thereof for textile finishing.
Abstract:
The present invention relates to textile two- or three-dimensional structures formed from fibers and/or ribbons and swellable materials, the fibers and/or ribbons present in the structure and also the swellable materials each being present in such an amount that the fibers and/or ribbons are encased by the swellable materials and the voids in the structure are, in the swollen state, partially or completely filled by materially bound water and the swellable materials used being aqueous emulsions of (co)polymers of at least one ethylenically unsaturated monomer MON which are applied to the fibers and/or ribbons.