Auxiliary materials

As well as testing the reactants, as described in Section 22.1, we should also test auxiliary materials. For example, nitrogen trifluoride reacted with silica, which was used as a drying agent. Whenever a new batch of silica was installed, there was a rise in temperature, which the operators never reported and in time accepted as normal. They were walking along the precipice described in Section 22.1, and one day the temperature rise got out of control. 

In practice, production processes are usually rather more complex. Raw materials are usually impure and thus some pre-purification steps may be required. Obviously impurities in the raw materials will incresae the probability of impurities and byproducts occuring in the output stream from the chemical conversion step. Even using pure raw materials, most chemical conversion are incomplete and often lead to the formation of undesirable byproducts. Furthermore often additional (auxiliary) materials are used (for example catalysts, specific solvents), which have to be separated from the desired product. Thus, in typical production processes a large number of separation steps are required. 

The mass-related metrics shown in Figure 5.11 indicate that the amount of a substrate (see also byproduct formation), an auxiliary material for reaction, and of a solvent have to be reduced. The detailed view of the mass indices of the pilot scale, for example, the segments Substrates and Aux (R) and the size of segments Substrates (excess) and Aux (R) of the environmental factor E, deliver the information listed in Table 5.2 108% base and 162% auxiliary (R) are used. The measure to increase base addition for recycling purposes was successful at the expense of 193% base, much auxiliary material Aux (R) was saved in operation scale (reduction from 162% to only 13%). This leads to an overall... 

Figure 5.16 Fractions of global-warming scores (% of total impact) for Auxiliary (R) and base used to recycle Auxiliary (R) at different stages of process development. Corresponding mass metrics can be found in Figure 5.10 (see column S ) The base is used as substrate (S) and the auxiliary material (Aux (R)) is used during the reaction.

Our case studies prove that optimization objectives generally followed in synthesis design and during scale up show a high potential for increasing resource efficiency. These objectives are, for example, increases of yield and the recycling efficiency of solvents and auxiliary materials. 

Raw materials and auxiliary products used in a process as well as materials of construction for equipment items can be the eause of scale-up effects . Pure raw and auxiliary materials must be used in laboratory studies to eliminate the influence of impurities on the ehoice of the process route, catalyst selection, and search for satisfactory process conditions. However, pure chemicals are usually too expensive to use for manufacture on a commercial scale. It is common practice to use raw materials of technical grade in a full-scale plant. These materials contain impurities, which can act as catalysts or inhibitors. They can react with reactants or intermediates, thereby decreasing yields and selectivities of desired produets. Therefore, raw materials of technical grade, even from different suppliers must first be tested on laboratory scale. 

In LCI databases no process data are found for the process of mechanical recycling of PVC. Therefore, some rough assumptions have been made for the definition of the process, like energy use, auxiliary material use and emissions (including phthalate emissions). 

Again, the waste treatment scenario with incineration has by far to the highest score for human toxicity. The scores for the other scenarios are more or less the same. The incineration of EoL PVC will lead to toxic emissions of metals (arsenic, lead, chromium, see Table 5) causing human health effects. However, the most important contribution to the human health effect is caused by the emission of mercury in the upchain processes of the production of mercury and sodium hydroxide. Sodium hydroxide is an auxiliary material in the waste incineration process. Mercury... 

In a review of incidents involving explosive reactivity of liquid chlorine with various organic auxiliary materials, two involved hydrocarbons. A polypropylene filter element fabricated with zinc oxide filler reacted explosively, rupturing the steel case previously tested to over 300 bar. Zinc chloride derived from the oxide may have initiated the runaway reaction. Hydrocarbon-based diaphragm pump oils or metal-drawing waxes were violently or explosively reactive [8], A violent explosion in a wax chlorination plant may have involved unplanned contact of liquid chlorine with wax or chlorinated wax residues in a steel trap. Corrosion products in the trap may have catalysed the runaway reaction, but hydrogen (also liberated by corrosion in the trap) may also have been involved [9],... 

In agreement with the Reich Ministry of Economics, I accordingly direct you to stockpile that amount of the raw and auxiliary materials indicated by you as necessary for the execution of the mobilization order, which would cover the requirements for three months.. .. It is incumbent upon you to register as priority transports the quantities of these materials required, for the first four weeks, from the beginning of the mobilization, with the military-economics department concerned. Please inform me as soon as possible that the directives issued to you for stockpiling have been carried out. 

Environmental problems are often caused by the use of auxiliary materials, e.g. processes using Clemmensen reduction with amalgamated Zn as reducing agent [31, 35]. 

U.S. 5,536,949 Charge injection auxiliary material and organic electroluminescence device containing the same... 

The reagents, carrier gases and auxiliary materials must be as pure as possible. 

In the 13 case studies documented processes and experiences of attempts to substitute hazardous substances in the 1980s and 1990s were examined. The aim of the choice of cases was to cover a wide spectrum of substitution conditions consumer-close and consumer-remote products, product auxiliary materials and process auxiliary materials, SMEs and large-scale industiy, environment, consumer and occupational health and safety subjects, technical and organisational iimova-tions. 

Customer orientation and initial solution-free formulation of customers wishes, as an orientation for product development, appear to be promising approaches for innovations with regard to the application safety of chemicals-based products. However, the initiative for this is not mainly due to substance manufacturers, but rather to the chemicals users being close to the consumers. To what extent the commercial/industrial chemicals end-users (users of production auxiliary materials that are not included in the product) also transform the latent desire for application-safe products into effective demand behaviour, depends on other constellations of motives than those of private end-consumers. The employers liabihty insurance, chambers of commerce and industry, branch associations, trade unions and management boards of large-scale companies play a key role in making quality and competition effective as drivers for innovation here too. 

Transportation processes upstream of succinic acid and 1,4-butanediol are disregarded, except for sea transport of crude oil. Treatment of wastewater generated in the plant and preparation of catalysts used in production are deemed negligible factors and omitted from this evaluation. Based on data provided from the plant of Showa Denko, auxiliary materials used in production other than succinic acid and 1,4-butanediol account for a mere 0.2% of raw materials by total weight. They are omitted from this evaluation. Additionally, we do not evaluate film processing in this study, since the process is nearly identical for all products. 

For further calculation and assessment of business cases the performance of the operating or auxiliary material and the know-how of the supplier are now decisive factors, too. 

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