Other manufacture routes

Other manufacturing routes for carbon products based on mesophase are almost certain to be devised in the future and will depend upon an understanding of the rheological behaviour of the mesophase pitch. 

PBBs are normally prepared by direct bromination of biphenyl, using an aluminium chloride catalyst other manufacturing routes, using Friedal Craft processes, are possible [97]. The principal grade produced was basically a hexabromo- (Fire-... 

Vinyl fluoride (fluoroethene), is manufactured from the cataly2ed addition of hydrogen fluoride to acetylene. It is used to prepare poly(vinyl fluoride) which has found use in highly weather-resistant films (Tedlar film, Du Pont). Poly(vinyhdene fluoride) also is used in weather-resistant coatings (see Eluorine compounds, organic). The monomer can be prepared from acetylene, hydrogen fluoride, and chlorine but other nonacetylenic routes are available. 

Pyrrohdinone (2-pyrrohdone, butyrolactam or 2-Pyrol) (27) was first reported in 1889 as a product of the dehydration of 4-aminobutanoic acid (49). The synthesis used for commercial manufacture, ie, condensation of butyrolactone with ammonia at high temperatures, was first described in 1936 (50). Other synthetic routes include carbon monoxide insertion into allylamine (51,52), hydrolytic hydrogenation of succinonitnle (53,54), and hydrogenation of ammoniacal solutions of maleic or succinic acids (55—57). Properties of 2-pyrrohdinone are Hsted in Table 2. 2-Pyrrohdinone is completely miscible with water, lower alcohols, lower ketones, ether, ethyl acetate, chloroform, and benzene. It is soluble to ca 1 wt % in aUphatic hydrocarbons. 

The other CO route for adipic acid manufacture involves 1,4-addition of CO and O2 to butadiene to produce an intermediate, which is subsequently hydrogenated and hydroly2ed to adipic acid (50). This is called the oxycarbonylation process. Both the BASF and the oxycarbonylation processes have been intensively investigated. 

Several synthetic pathways for the commercial manufacture of quinacridone pigments have been published. In this context, only those routes are mentioned which were developed for industrial scale production. There are four options, the first two of which are preferred by the pigment industry. It is surprising to note that these are the methods which involve total synthesis of the central aromatic ring. On the other hand, routes which start from ready-made aromatic systems and thus might be expected to he more important actually enjoy only limited recognition. 

Acetylene (Figure 13.1) is widely used as a chemical raw material and fuel for oxyacetylene torches. It was once the principal raw material for the manufacture of vinyl chloride (see reaction 13.2.4), but other synthetic routes are now used. Acetylene is a colorless gas with an odor resembling garlic. Though not notably toxic, it acts as an asphyxiant and narcotic and has been used for anesthesia. Exposure can cause headache, dizziness, and gastric disturbances. Some adverse effects from exposure to acetylene may be due to the presence of impurities in the commercial product. 

PO was manufactured by the chlorohydrin route first during World War I in Germany by BASF and others. This route (below) involves reaction of propylene with hypochlorous acid followed by treatment of the resulting propylene chlorohydrin with a base such as caustic or lime. The products of the second reaction are PO and sodium or calcium chloride (Fig. 10.22). 

The manufacture of fatty alcohols from natural oils can be made either through the methyl ester route or fatty acid route. These two methods are both well established and are strongly competitive with each other. Commercial plants around the world use either route. Figure 9 shows the manufacturing routes of fatty alcohols from natural fats and oils. 

Primary shaping can also be applied to materials that cannot be processed with other manufacturing techniques. An advantageous material and energy balance is ensured by the direct route from raw material to the molding or the final product. 

In principle, there are as many combinations of fibre and matrix available for textile-reinforced composites as there are available for the general class of composite materials. In addition to a wide choice of materials, there is the added factor of the manufacturing route to consider, since a valued feature of composite materials is the ability to manufacture the article at the same time as the material itself is being processed. This feature of composite materials contrasts with the other classes of engineering materials (metals, ceramics, polymers), where it is usual for the material to be produced first (e.g. steel sheet) followed by the forming of the desired shape. 

Other Aspen Batch Plus models developed earlier in the project life-cycle have been used to identify potential throughput issues in the technology transfer plant, provide an estimation of the amount of iodo contaminated effluent from a process and comparison of manufacturing routes to enable potential problems on scale-up to be considered in decision making. The models are also used to evaluate potential manufacturing facilities, not only for full scale but also for development campaigns. 

PAEK are commonly described in terms of an E and a K which refer to the sequence of ether and ketone units in the structure. The most common PAEK are polyaryletheretherketone (PEEK), polyaryletherketone (PEK) and polyaryletherketoneketone (PEKK). PEEKK and PEKEKK are also produced commercially. There are two basic manufacturing routes nucleophilic and electrophilic. Some polymers (e.g., PEKK) are only made commercially hy electrophilic processes whereas others (such as PEEK, PEK and PEKEKK) can be made by either route. 

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