Reuse importance

The third largest LLDPE film application in North America is industrial liners, greater than 250 million kilograms per year. Industrial liners are used inside cans, drums, cardboard boxes and the like to prevent spillage, contamination, moisture, and ease of container reuse. Important film attributes are puncture resistance, tear strength, and tensile strength. Common LLDPE melt indices are 0.5-2 g/10 min with densities of 0.917-0.930 g/cm. mLLDPE finds little application here because of higher raw material costs. 

The component C in the separated extract from the stage contact shown in Eigure 1 may be separated from the solvent B by distillation (qv), evaporation (qv), or other means, allowing solvent B to be reused for further extraction. Alternatively, the extract can be subjected to back-extraction (stripping) with solvent A under different conditions, eg, a different temperature again, the stripped solvent B can be reused for further extraction. Solvent recovery (qv) is an important factor in the economics of industrial extraction processes. 

Most carbide acetylene processes are wet processes from which hydrated lime, Ca(OH)2, is a by-product. The hydrated lime slurry is allowed to settle in a pond or tank after which the supernatant lime-water can be decanted and reused in the generator. Federal, state, and local legislation restrict the methods of storage and disposal of carbide lime hydrate and it has become increasingly important to find consumers for the by-product. The thickened hydrated lime is marketed for industrial wastewater treatment, neutrali2ation of spent pickling acids, as a soil conditioner in road constmction, and in the production of sand-lime bricks. 

Liquid SO is usually produced by distilling SO vapor from oleum and condensing it. This operation is normally carried out at a sulfuric acid plant where the stripped oleum can be readily refortified or reused. EHminating all traces of sulfuric acid from the SO vapor stream is important to minimize polymerization of the Hquid condensate. When this is done, it is frequently possible to utilize unstabilized Hquid SO if precautions are taken to prevent it from freezing before use. At some plants, gaseous 100% SO is utilized directly instead of producing Hquid. 

An important by-product of most energy technologies is heat. Few energy conversion processes are carried out without heat being rejected at some point in the process stream. Historically, it has been more convenient as weU as less cosdy to reject waste heat to the environment rather than to attempt significant recovery. The low temperatures of waste heat in relation to process requirements often make reuse impractical and disposal the only attractive alternative (see Process energy conservation). 

The reaction vessel (nitrator) is constructed of cast iron, mild carbon steel, stainless steel, or glass-lined steel depending on the reaction environment. It is designed to maintain the required operating temperature with heat-removal capabiUty to cope with this strongly exothermic and potentially ha2ardous reaction. Secondary problems are the containment of nitric oxide fumes and disposal or reuse of the dilute spent acid. Examples of important intermediates resulting from nitration are summarized in Table 3. 

Transesterification has a number of important commercial uses. Methyl esters of fatty acids are produced from fats and oils. Transesterification is also the basis of recycling technology to break up poly(ethylene terephthalate) [25038-59-9] to monomer for reuse (29) (see Recycling, plastics). Because vinyl alcohol does not exist, poly(vinyl alcohol) [9002-89-5] is produced commercially by base-cataly2ed alcoholysis of poly(vinyl acetate) [9003-20-7] (see Vinyl polymers). An industrial example of acidolysis is the reaction of poly(vinyl acetate) with butyric acid to form poly(vinyl butyrate) [24991-31-9]. 

Enzymatic Reactors Adding free enzyme to a batch reactor is practical only when the value of the enzyme is relatively low. With expensive enzymes, reuse by retaining the enzyme with some type of support makes great economic sense. As some activity is usually lost in tethering the enzyme and the additional operations cost money, stabihty is very important. However, many enzymes are stabilized by immobilization thus, many reuses may be possible. 

Adhesives and resins are one of the most important raw materials in wood-based panels. Thus, each question concerning the life cycle assessment and the recycling of bonded wood panels does bring into question the adhesive resins used. This includes, for example, the impact of the resin on various environmental aspects such as waste water and effluents, emission of noxious volatile chemicals during production and from the finished boards, or the reuse for energy generation of wood panels. The type of resin has also a crucial influence on feasibility and efficiency for several material recycling processes. 

Counter-current rinsing and rinse-water reuse are useful tips for reducing usage. Counter-current contact systems are more efficient in promoting heat and mass exchanges, which are important to gas absorption, extraction, and many types of chemical reactions. 

Although the reactants have only limited solubility in the catalyst phase, the rates of hydrogenation in [BMIM][SbFg] are almost five times faster than for the comparable reaction in acetone. All ionic catalyst solutions tested could be reused repeatedly. The loss of rhodium through leaching into the organic phase lay below the detection limit of 0.02 %. These results are of general importance for the field of... 

Yet, the development of processing and modification methods is not finished. Further improvements need to be expected so that it might be possible to substitute technical fibers in composites even more widely. Natural fibers are reusing raw materials and they are recyclable. When recognizing the need for recycling and preserving natural resources, such a substitution is very important. 

Addition of organolithiutn reagents in toluene to A-cyclohexyl enimines in the presence of chiral nonracemic diethers or diamines (1.2-2,4 equiv) gives, after hydrolysis, //-substituted aldehydes2. It is important to note that these reactions do not occur in the absence of the chiral additive which can be recovered quantitatively for reuse without loss of enantiomeric purity6. 

To keep product yield at a maximum it is important that the solubility of product in the spent acid be kept to a minimum. This also facilitates removal of traces of product from the spent acid so that it can be either fortified and reused, reused to make lower nitro compds, or neutralized and discharged as non-polluting waste material... 

The purpose of the depolymerization of polyurethanes is the isolation of polyols, which may be reused in file production of PUR. Important solvolysis... 

Nowadays economy and ecology render the reuse of the sulfite solution increasingly important. Normally the scrubber liquor is recovered as dilution water directly in the neutralization of sulfonation plant or in the slurry preparation unit of synthetic detergent plants. In some special cases, when the presence of sulfites is incompatible with the slurry composition, it is possible to install as optional a sulfite oxidation unit. This oxidation takes place with atmospheric air. 

Room temperature ionic liquids are air stable, non-flammable, nonexplosive, immiscible with many Diels-Alder components and adducts, do not evaporate easily and act as support for the catalyst. They are useful solvents, especially for moisture and oxygen-sensitive reactants and products. In addition they are easy to handle, can be used in a large thermal range (typically —40 °C to 200 °C) and can be recovered and reused. This last point is particularly important when ionic liquids are used for catalytic reactions. The reactions are carried out under biphasic conditions and the products can be isolated by decanting the organic layer. 

A most important issue in the present method was the ability to reuse the catalyst, without losing its activity. This proved to be one of the most salient advantages offered by 4. Catalyst recovery was straightforward, since it involved a simple filtration step. In our hands, it was possible to perform several cycles of catalyst reuse by simple filtration and washing steps (see Table 7). 

---