What mass ranges are reported

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Reference no: EM132489787

Organic Chemistry of the Main Group Elements

Answer the following questions:

Question 1. Write an account of approximately 800-1000 words on the catalytic Wittig olefination reaction. The lectures describe the Wittig reaction but how can it be made catalytic in phosphorus? On the handout for organophosphorus chemistry there is a paragraph describing how this can be achieved, together with references that will be a good starting point to help you.

Question 2. Read the publication Org. Lett.2006, 597 and answer the following questions:
a) Draw a mechanism for the formation of product 5a from compound 11a (see Scheme 2).
b) Draw a mechanism for the formation of product 12a from compound 5a (see Scheme 2) and explain the preference for the cis ring junction. Explain the preference for the Z isomer of the side-product 13a and suggest how the amount of this compound could be minimized.
c) Explain the preference for the Z isomer of the product 4a from phosphonate 15a.
d) The final step in the synthesis (Scheme 4) removes the silyl group. What was the purpose of the silyl group?

Question 3. Draw a mechanism for the following reaction and comment on any aspects of selectivity.

Problem solving essay. The Chemistry of Energetic Materials.

DoctorPeterPortius

"Recent developments in the synthesis, reactivity and characterisation of nitrogen-rich materials".

Nitrogen-rich materials are key-aspect of modern developments in the science of propellants, explosives and pyrotechnics. Chemists play an important role in this area as they investigate and develop syntheses for novel nitrogen-rich compounds and characterise their reactivity and energetic properties. Fundamentally, the high energy density of nitrogen-rich compounds arises from a high abundance of weak N-N bonds in the molecular structure and the extreme thermodynamic stability of dinitrogen, into which all nitrogen-rich compounds decompose in their intended use in energetic materials. This assessment consists of an essay that is linked to a problem-solving task.

Essay
You are asked to write an essay on the subject of nitrogen-rich energetic materials (1000 words, +/- 10%) in which you explainand put into context with each other, the conceptsgiven below (not in order):
- bulk density, crystal density, energy density
- kinetic stability and thermodynamic stability of an energetic compound
- enthalpy of formation, heat of decomposition, volume and heat of explosion
- the composition of the gas formed in an explosion
- velocity of detonation, reaction rate, reaction front propagation, deflagration, detonation, explosion
- bond dissociation enthalpies
- classes of nitrogen-rich compounds and principal routes for their synthesis
- primary explosives, secondary explosives, propellants and gas generants.

You will then use these concepts to rationalise why nitrogen-rich compounds play a role in certain areas in explosives, propellants and pyrotechnics applications. Your study is assisted by the refe-rences to the literature made during lectures 1 to 10, and additional ones based on review papers and papers reporting results of original research (10 in total, simple internet links, or citing lecture materialis not permitted).

Problem solving
Using the key reference H. Gao, J. M. Shreeve "Azole-based energetic salts" Chem. Rev. 111, 2011, 7377-7436, find up to ten publications reporting results of original research into compound class 5,5--azobistetrazolate salts. It is very important that you not just list material from several papers, but critically analyse and compare the results. Using coherent text (ca. 400 words) in which you cite the appropriate references, describe the compounds known in this class, how they are synthesised, what energetic properties they have, and finally provide answers to the question given below. Each item must have the appropriate reference attached.

Question 1: What mass ranges are reported for the pure nitrogen-rich products ?

Question 2: How have they been characterised ?

Question 3: What are their properties in terms of energetic materials chemistry ?

Question 4: Which is the most impact sensitive compound ?

Question 5: Which compound has the highest thermal decomposition onset temperature ?

Reference no: EM132489787

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