Abstract: The present invention relates to processes for transesterification, comprising the steps of A) mixing an organic acid a) with an ester b) and B) transferring the alcohol radical of the ester b) to the acid a) to obtain the ester of the acid a) and the acid of the ester b), step B) being carried out in a still.

Abstract: The invention relates to surface enhancements for composite mouldings made from polymeric materials and to the use thereof in solar systems. These solar systems may be solar reflectors for concentrating solar radiation, flexible photovoltaic composite films, or CPV (Concentrated Photovoltaics) lenses for concentrating solar radiation. The surface enhancement comprises a self-healing coating based on crosslinkable fluoropolymers, e.g. PFEVE (polyfluoroethylene alkylvinyl ethers). These coatings exhibit good optical properties, can be used in outdoor applications, more particularly in solar applications, over very long periods of time, exhibit self-cleaning properties, and in particular are self-healing in relation to mechanical damage—such as scratching.

Abstract: The present invention relates to laminated solar concentration devices and to the production thereof from polymeric materials. The inventive solar concentration devices can be employed in photovoltaic systems or in solar thermal energy systems. The inventive solar concentration devices comprise Fresnel lenses and enable the efficient concentration of solar radiation onto objects such as solar cells or absorber units, irrespective of the geometry thereof. This relates, for example, to the area of a high-performance solar cell as used in concentrated photovoltaics (CPV), and equally to absorbers which are used in concentrated solar thermal energy systems (CSP). The invention in particular relates to the use of an UV- and weathering-stabilizer package for said laminated solar concentration devices, for improving optical lifetime and weathering resistance, and for preventing delamination.

Abstract: The present invention relates to a concentrator for focusing solar radiation, having surface structuring in the form of one or more Fresnel lenses on the lower side, and to the production thereof from polymeric materials by means of a specific extrusion process. The inventive concentrator can be employed in plants utilizable for photovoltaic or solar heating purposes, and has the required durability and performance in demanding climatic zones. The inventive concentrator enables particularly economic production and efficient concentration of solar radiation onto objects such as solar cells or absorber units, irrespective of the geometry thereof. The inventive concentrator has high longevity and—combined with this—high optical performance when employed in extreme and demanding climatic zones.

Abstract: Alpha-hydroxycarboxylic esters are prepared by a continuous process in which alpha-hydroxycarboxamide is reacted with an alcohol in the presence of a catalyst to obtain a product mixture which contains alpha-hydroxycarboxylic ester, ammonia, unconverted alpha-hydroxycarboxamide and alcohol, and catalyst; wherein reactant streams containing an alpha-hydroxycarboxamide, an alcohol and a catalyst are fed into a pressure reactor. The reactant streams are reacted with one another in the pressure reactor at a pressure in the range of 1 bar to 100 bar; and the product mixture is depleted in alcohol and ammonia by distilling off ammonia at a pressure which is constantly kept greater than 1 bar without the aid of additional stripping media. The continuous process can be employed particularly advantageously on the industrial scale.

Abstract: The invention relates to the use of non-transparent, methacrylate-containing one-, two- or multi-layered films in flexible photovoltaic systems, and to the production of said films by extrusion coating, extrusion lamination (adhesive lamination, melt lamination or hotmelt lamination) or glue lamination. For this purpose, e.g. a thin, inorganic or metallically coated film, for example made of PET, is laminated or coextruded with a weather-resistant film, e.g. a film made of PMMA or PMMA polyolefin coextrudate. In particular, laminates are produced in which at least one of the two layers is non-transparent. An optional inorganic oxide or metal layer has the property of a high barrier effect against water vapour and oxygen while the PMMA layer exhibits weather resistance stability.

Abstract: The invention relates to the production of a transparent, weather-resistant barrier film by lamination, extrusion lamination (adhesive lamination, melt lamination or hotmelt lamination) or extrusion coating. The film can also contain a scratch-resistant coating. For this purpose, two or more transparent film composites, which consist in each case of two externally disposed polyolefin or polyester layers which are in each case inorganically coated and glued to the inorganic layer on the inside, are connected to each other. Said composite is laminated with a weather-resistant, transparent film (e.g. PMMA or PMMA polyolefin coextrudate or PMMA polyester coextrudate). The inorganic oxide layers have the property of a high optical transparency while having at the same time a good barrier effect against water vapour and oxygen while the PMMA layer exhibits weather resistance stability.

Abstract: The present invention relates to a process for preparing carboxamides by hydrolysing carbonitriles in the presence of a catalyst comprising manganese dioxide, wherein the reaction mixture added to the catalyst comprising manganese dioxide has a pH in the range of 6.0 to 11.0 and the hydrolysis is performed in the presence of an oxidizing agent. The present invention further relates to a process for preparing alkyl (meth)acrylates, the process having a hydrolysis step according to the process described above.

Abstract: The present invention relates to processes for preparing alkyl (meth)acrylates, comprising the steps of transesterifying an alkyl ?-hydroxycarboxylate with (meth)acrylic acid to obtain alkyl (meth)acrylates and ?-hydroxycarboxylic acid, and dehydrating the ?-hydroxycarboxylic acid to obtain (meth)acrylic acid.

Abstract: The present invention relates to a process for preparing carboxamides by hydrolysing carbonitriles in the presence of a catalyst comprising manganese dioxide, wherein the reaction mixture added to the catalyst comprising manganese dioxide has a pH in the range of 6.0 to 11.0 and the hydrolysis is performed in the presence of an oxidizing agent. The present invention further relates to a process for preparing alkyl (meth)acrylates, the process having a hydrolysis step according to the process described above.

Abstract: The present invention relates to a process for preparing alkyl(meth)acrylates, characterized in that the process has a step in which a cyanohydrin is hydrolysed with an enzyme whose residual activity after the conversion of methacrylonitrile in the presence of 20 mM cyanide ions at 20° C. after 30 min is at least 90% of the residual activity of the enzyme which has been used under otherwise identical conditions in the absence of cyanide ions.

Abstract: Continuous process for preparing alpha-hydroxycarboxylic esters, in which the reactants reacted are alpha-hydroxycarboxamide with an alcohol in the presence of a catalyst to obtain a product mixture which comprises alpha-hydroxycarboxylic ester, ammonia, unconverted alpha-hydroxycarboxamide and alcohol, and catalyst; wherein a?) reactant streams comprising, as reactants, an alpha-hydroxycarboxamide, an alcohol and a catalyst are fed into a pressure reactor; b?) the reactant streams are reacted with one another in the pressure reactor at a pressure in the range of 1 bar to 100 bar; c?) the product mixture which results from step b) and comprises alpha-hydroxycarboxylic ester, unconverted alpha-hydroxycarboxamide and catalyst, and also ammonia and alcohol, is discharged from the pressure reactor; and d?) the product mixture is depleted in alcohol and ammonia by distilling off ammonia at a pressure which is constantly kept greater than 1 bar without the aid of additional stripping media.

Abstract: Continuous process for preparing alpha-hydroxycarboxylic esters, in which the reactants reacted are alpha-hydroxycarboxamide with an alcohol in the presence of a catalyst to obtain a product mixture which comprises alpha-hydroxycarboxylic ester, ammonia, unconverted alpha-hydroxycarboxamide and alcohol, and catalyst; wherein reactant streams comprising, as reactants, an alpha-hydroxycarboxamide, an alcohol and a catalyst are fed into a pressure reactor; the reactant streams are reacted with one another in the pressure reactor at a pressure in the range of 1 bar to 100 bar; and the product mixture is depleted in alcohol and ammonia by distilling off ammonia at a pressure which is constantly kept greater than 1 bar without the aid of additional stripping media. The continuous process can be employed particularly advantageously on the industrial scale.

Abstract: The present invention relates to processes for transesterification, comprising the steps of A) mixing an organic acid a) with an ester b) and B) transferring the alcohol radical of the ester b) to the acid a) to obtain the ester of the acid a) and the acid of the ester b), step B) being carried out in a still

Abstract: The present invention relates to processes for preparing alkyl (meth)acrylates, comprising the steps of transesterifying an alkyl ?-hydroxycarboxylate with (meth)acrylic acid to obtain alkyl (meth)acrylates and ?-hydroxycarboxylic acid, and dehydrating the ?-hydroxycarboxylic acid to obtain (meth)acrylic acid.

Abstract: The invention relates to a process for continuous preparation of alkyl (meth)acrylates by transesterification of methyl (meth)acrylate using alcohols which are high-boiling relative to methanol. A particular workup technique achieves product qualities which have hitherto not been attained. Very high space-time and overall yields can also be achieved.

Abstract: The invention relates to a process for continuous preparation of alkyl (meth)acrylates by transesterification of methyl (meth)acrylate using alcohols which are high-boiling relative to methanol. A particular workup technique achieves product qualities which have hitherto not been attained. Very high space-time and overall yields can also be achieved.