Questions and Problems

Last updated
Save as PDF

Page ID: 307112

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

Access to and use of the internet is assumed in answering all questions including general information, statistics, constants, and mathematical formulas required to solve problems. These questions are designed to promote inquiry and thought rather than just finding material in the text. So in some cases there may be several “right” answers. Therefore, if your answer reflects intellectual effort and a search for information from available sources, your answer can be considered to be “right.”

1. Discuss advantages that biological feedstocks have over petroleum. Are there disadvantages?

2. What is a fundamental chemical difference between petroleum and biological feedstocks?

3. Potassium permanganate, sodium dichromate, and hydrogen peroxide may all three be used as reagents to react with organic molecules. What kind of reaction to they cause to occur? Which of these would be regarded as the greenest reagent and why is that so?

4. Name three kinds of reactions used in processing feedstocks. Which is best from the viewpoint of green chemistry?

5. Name several fractions of biomass that can be used for feedstocks. Which of these is the least useful?

6. How are oils extracted from plant sources?

7. Use chemical formulas to make the argument that carbohydrates are a more oxidized chemical feedstock than hydrocarbons.

8. Before the petrochemicals industry developed, the use of coal in making steel gave rise to a major organic chemicals industry? Explain why this was so and list some of the products that were made

9. Name some categories of chemicals routinely produced by fermentation.

10. Which pharmaceutical material has been produced by fermentation for many years?

11. What is the first, most important consideration in developing a fermentation process for production of a chemical?

12. What is the significance of temperature in fermentation processes? What happens if temperature is too high?

13. Which chemical is made in largest quantities by fermentation?

14. In which fundamental respect are plants more efficient producers of material than fermentation?

15. Which relatively recent advance in biotechnology has greatly increased the scope of materials potentially produced by plants?

16. Why are hybrid poplar trees particularly important in the production of raw materials?

17. Describe the structural characteristics of glucose and other carbohydrates that make them good platforms for chemical synthesis.

18. Give a disadvantage and an advantage of the use of cellulose as a source of glucose.

19. List some of the hazards associated with the chemical synthesis of adipic acid used to make nylon.

20. Give a major concern with the use of benzene as a feedstock.

21. What is a chemical characteristic of 3-dehydroshikimic acid that could lead to much greater uses for it?

22. Although the chemical formula of glucose is C₆H₁₂O₆, that of the cellulose polymer made from glucose is (C₆H₁₀O₅)_n where n is a large number. Since cellulose is made from glucose, why is the cellulose formula not (C₆H₁₂O₆)_n?

23. Why is wood pulp consisting mostly of cellulose, treated with oxidants? Which oxidants are preferred, and which has lost favor?

24. Give some examples of useful chemically modified cellulose. Which of these has proven to be rather dangerous?

25. In ruminant animals that have bacteria in their stomachs that digest cellulose, the rumen bacteria and the organic acids they generate are passed on through the digestive tract where the bacterial biomass is dissolved, with the products and the organic acids previously generated absorbed by the animal as food. Suggest why basic limestone is used in the large batch processes that use rumen bacteria in digesters to produce organic acids from cellulose.

26. Why is it difficult to deal with lignin as a source of chemical feedstocks? What is the current main use of waste lignin?

27. Using internet resources, try to find an example of an operational biorefinery that is either in commercial operation or at a pilot plant level. What materials does it process and how does it process them? What are its main products?

28. Give the main advantage of biopolymers from an environmental viewpoint.

29. Which structural feature of hydroxyalkanoates enables them to make polymeric molecules?

30. What was the original source of poly(hydroxyalkanoate) polymers? How is it now proposed to produce them?

31. Although enzymes have not developed specifically to act upon synthetic compounds, they have some specific advantages that make them attractive for carrying out chemical processes on synthetic compounds. What are some of these advantages?

32. Name two chemicals for which it has been shown that enzymatic processes can actually convert synthetic raw materials to chemical products normally made by nonbiological chemical reactions.