Hybrid Approach

The solvent selection problem for the removal of phenol from wastewater has been solved with the ProCAMD (see Table 5). The summarized results from ProCAMD are shown in Figure 6. Compared with butyl acetate and toluene, this solvent has been found to have a higher F (eqn [1]) and is environmentally acceptable.

Identification of a solvent for morphine

Problem formulation In the production of morphine a solvent is needed for dissolving the solid. Known solvents for morphine include cyclohexane, tetrachloromethane, toluene and benzene. It is desired to find alternative solvents capable of dissolving morphine. Furthermore, in order not to contaminate the product with toxic substances, in case of solvent inclusions after crystallization, the compound should be nonaromatic and have a low toxicity.

Constraint selection Solubility is a mixture property. To be able to predict solubility to some degree of accuracy it is necessary to have access to a method for calculation of activity coefficients. For complex compounds (such as morphine) very few group-contribution-based property estimation methods are able to describe the molecular structure (see Figure 7). Therefore, the search for alternative solvents is carried out using pure component properties as criteria for evaluation. It is well known that two compounds having similar solubility parameters (3) are highly likely to be miscible. The search for solvents for morphine can therefore be expressed as a search for compounds being liquid at ambient temperatures and having a solubility parameter as close as possible to that of morphine (3 = 26.3 MPa1/2).

Figure 6 Results for phenol-wastewater separation (screenshot from ProCAMD).

Design specifications

• Compound type acyclic alkanes, ethers, esters, aldehydes, ketones, alchohols;

• 22 < § < 30 (exclusion of the lowest ranking candidates);

• performance measure |26.3 — §| should be as low as possible.

Generation of alternatives The ProCAMD package (see Table 5) was used, generating 348 candidates fulfilling the requirements. After performing a structure search to identify substances with known CAs registry numbers two candidates, 1,5-pentanediol and acetol, were selected based on having a solubility parameter close to that of morphine.

Figure 7 Molecular structure of morphine.

Analysis and verification To verify the predicted values of the properties used as design specifications a search in available databases was carried out and the experimental values compared to the predicted. Furthermore the RTECS database (see Table 5) was consulted in order to investigate the health and environment properties of the selected compounds. The result of the investigations and the predicted properties are shown in Table 6.

Candidate selection From the data listed in Table 6 it is clear to see that among the known and generated solvents 1,5-pentanediol is the most promising candidate and should be selected for further testing in an experimental setting.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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