Process improvements

Benchmarking uses total quality management principles to integrate safety management techniques, existing improvement efforts and technical tools into a disciplined 

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Property Improvement Processes Using Molecular Rearrangement ... 

These acid rhodamines are usually used for sHk and wool because they have level dyeing properties and show good fastness to alkaU however, they have poor lightfastness. An improved process for manufacturing 3,6-diaminosubstituted xanthenes is reaction of the inner salts of... 

The catalytic vapor-phase oxidation of propylene is generally carried out in a fixed-bed multitube reactor at near atmospheric pressures and elevated temperatures (ca 350°C) molten salt is used for temperature control. Air is commonly used as the oxygen source and steam is added to suppress the formation of flammable gas mixtures. Operation can be single pass or a recycle stream may be employed. Recent interest has focused on improving process efficiency and minimizing process wastes by defining process improvements that use recycle of process gas streams and/or use of new reaction diluents (20-24). 

Alcohol autoxidation is carried out in the range of 70—160°C and 1000—2000 kPa (10—20 atm). These conditions maintain the product and reactants as Hquids and are near optimum for practical hydrogen peroxide production rates. Several additives including acids, nitriles, stabHizers, and sequestered transition-metal oxides reportedly improve process economics. The product mixture, containing hydrogen peroxide, water, acetone, and residual isopropyl alcohol, is separated in a wiped film evaporator. The organics and water are taken overhead and further refined to recover by-product acetone and the... 

One reason for widespread interest in the use of surfactants as gas mobihty control agents is the effectiveness at concentrations of <0.1 wt % (156,163). Some surfactants are effective below their critical micelle concentration (164). This low chemical requirement can significantly improve process economics. 

Thus, CIS is a promising photovoltaic material, but improved processing techniques are needed to achieve commercial production of advanced high efficiency CIS alloy materials. Table 1 summarizes the laboratory and commercial status of significant PV technology. 

J. W. Carson and T. A. Royal, "In-Bin Blending Improves Process Control," Powder Handl Proc. (Sept. 1992). 

Future technology developments in paraffin alkylation will be greatly influenced by environmental considerations. The demand for alkylate product will continue to increase because alkylate is one of the most desirable components in modern low emission gasoline formulations. Increased attention will be focused on improving process safety, reducing waste disposal requirements, and limiting the environmental consequences of any process emissions. 

Over the years, improvements in aromatic alkylation technology have come in the form of both improved catalysts and improved processes. This trend is expected to continue into the future. 

The complex batch reactor is a specialized pressure vessel with excellent heat transfer and gas Hquid contacting capabiUty. These reactors are becoming more common in aLkylphenol production, mainly due to their high efficiency and flexibiUty of operation. Figure 2 shows one arrangement for a complex batch reactor. Complex batch reactors produce the more difficult to make alkylphenols they also produce some conventional alkylphenols through improved processes. 

The focus of commercial research as of the mid-1990s is on catalysts that give desired and tailored polymer properties for improved processing. Development of metallocene catalyst systems is an example. Exxon, Dow, and Union Carbide are carrying out extensive research on this catalyst system for the production of polyethylene and polypropylene. 

The LIMS software is essentially a database for tracking, reporting, and archiving lab data as well as scheduling and guiding lab activities. Graphical and statistical treatment of data for improved process control (qv) as well as preparation of certificates of analysis (COA) for the customer are some of the other features of a comprehensive LIMS package (30). 

T arene mixed terpenes, a pine-tar product extender plasticizer aids in dispersion of fillers softens product and improves processing... 

Do we have a quaUty process for rapid product development and market penetration Do we have a stream of product improvements Are we develop-ing common platforms for families of products (37) Are we developing improved processes concurrently with our new products How do we maintain our manufacturing processes at world-class levels (Fig. 5) (38) ... 

To improve processing and to plasticize the mbber compound, numerous processing agents have been used over the years, eg, petroleum and ester plasticizers, resins and tars, Hquid mbber peptizers, peptizers, fatty acids and derivatives from vegetable oils, and polyethylene and hydrocarbon waxes. 

PVB resins are also compatible with a limited number of plasticizers and resins. Plasticizers (qv) improve processibility, lower T, and increase flexibihty and resiUency over a broad temperature range. Usehil plasticizers include dibutyl and butyl benzyl phthalates, tricresyl and 2-ethylhexyl diphenyl phosphates, butyl ricinoleate, dibutyl sebacate, dihexyl adipate, triethylene glycol di-2-ethylbutyrate, tetraethylene glycol diheptanoate, castor oil, and others (64-73). 

Fig. 5. Synthetic pathway for d-hioXin. (Lonza synthesis). An improved process uses the chiral ferrocenyldisphoshine (36) to iatroduce stereospecificity...

Almost all industrial catalysts are developed by researchers who are motivated to improve processes or create new ones. Thus the organization that first uses a new catalyst is usually the one that has discovered it. This organization, however, only rarely becomes the manufacturer of the catalyst used on a large scale. Catalysts are for the most part highly complex specialty chemicals, and catalyst manufacturers tend to be more efficient than others in producing them. Catalyst manufacturing is a competitive industry. Catalyst users often develop close relations with catalyst manufacturers, and the two may work together to develop and improve proprietary catalysts. 

Pasteurized Process Cheese. Sodium citrate is used in pasteurized process and sHced cheese as an emulsifying salt to stabilize the water and oil emulsion and improve process cheese body and texture (64). 

Efforts have also been made to overcome compHcated processes. Methods to reduce the number of steps or to use new starting materials have been studied extensively. l-Amino-2-chloro-4-hydroxyanthraquinone (the intermediate for disperse red dyes) conventionally requires four steps from anthraquinone and four separation (filtration and drying) operations. In recent years an improved process has been proposed that involves three reactions and only two separation operations starting from chloroben2ene (Fig. 2). 

In the first case (22), almost stoichiometric amounts of sulfuric acid or chlorosulfonic acid are used. The amine sulfate or the amine chlorosulfate is, first, formed and heated to about 180 or 130°C, respectively, to rearrange the salt. The introduction of the sulfonic acid group occurs only in the ortho position, and an almost quantitative amount of l-aminoanthraquinone-2-sulfonic acid is obtained. On the other hand, the use of oleum (23) requires a large excess of SO to complete the reaction, and inevitably produces over-sulfonated compound such as l-amino-anthraquinone-2,4-disulfonic acid. Addition of sodium sulfate reduces the byproduct to a certain extent. Improved processes have been proposed to make the isolation of the intermediate (19) uimecessary (24,25). 

Dihydroxyanthraquinone. This anthraquinone, also known as quinizarin [81-64-1] (29), is of great importance in manufacturing disperse, acid, and vat dyes. It is manufactured by condensation of phthalic anhydride (27) with 4-chlorophenol [106-48-9] (28) in oleum in the presence of boric acid or boron trifluoride (40,41). Improved processes for reducing waste acid have been reported (42), and yield is around 80% on the basis of 4-chlorophenol. 

Diaminoanthraquinone is an important intermediate for vat dyes and disperse dyes, and is prepared by oxidizing leuco-l,4-diaminoanthraquinone with nitrobenzene in the presence of piperidine. An improved process has been reported (45). 

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