4. General Instructions for the following problems instructor might give additio

Question

4. General Instructions for the following problems instructor might give additional spectrum list problem contains some combination of the following information: IR UV peak, (with of absorption frequencies), mass spectrum or molecular major element on each IR neatly label the major peaks with the structural fragment which causes the absorption. Use the back of the page for calculation of molecular for notes, and the answer. DO NOT use the problem area for scratch work. Draw an expanded structural formula for the identified compound. Name the compound. For 2 of the six problems, attach a copy of a published reference IR spectrum (either from an on-line or hard copy source) with all the major absorption peaks clearly marked. (Make sure that you do not submit a gas-phase spectrum if the problem set shows a liquid or solution- phase spectrum.) Give proper citations to the source of the spectra. Consult the lab manual, the lab textbook by Pavia, et al., and the lecture textbook to help you with the analyses.

Explanation / Answer

To solve this type of problem

We need to have molecular formula

But no worries

We can calculate it from mass

Lets see example b)

M+ is 73

According to rule of 13

We should divide m+ by 13

73/13=5 (8)

5+8=13

So we can say we have 5 carbons and

13 hydrogen

But IR peak at 3297 shows that it may contain NH or OH

So previously out formula was C5H13

If we add N we need to substract it's equivalent CH2

So formula will be C4H9N

As there is one site of unsaturation

So it may ring or double bond

IR shows 3297 will be NH

And 2900 Shows CH

1080-1360 CN streaching

1600 will be NH Bending

So we answer is tetrahydropyrol

Give membered saturated ring with NH

So we can say that it is

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.