will teach u nmr
- Find the molecular weight from molecular ion in the mass spectrum
- What functional groups are present from the IR ?
- What do the peaks at 7-8 ppm in the H-nmr and at 120-180 ppm in the 13C-nmr reveal ?
- Look at the integration in the H-nmr
- Use the above to get the molecular formula (make sure it matches the MW)
- Count the number of types of C in the 13 C-nmr. What does this tell you ?
- What hydrocarbon pieces the H-nmr indicate ?
- Using the chemical shifts how are these pieces connected together ?
- Symmetry ?
(particularly those between 120-180ppm)
- In the MS, the molecular ion occurs at m/z = 150 indicating the MW = 150 g / mol.
- The IR shows an C=O (1680 cm-1) and possible C-O (1250-1000 cm-1) but no -OH or -NH (around 3500 cm-1)
- 13 C-nmr shows 6 types of C, including a C=O (aldehyde or ketone, 213 ppm), and 3 ArC (178, 143 and 126 ppm) plus 2 other hydrocarbon C (63 and 34 ppm)
- H-nmr
2 x ArH | |||
2 x ArH | |||
isolated CH3 deshielded, possibly by O | |||
isolated CH3 slightly deshielded |
- The lack of a peak at about 9 ppm rules out an aldehyde and therefore suggests a ketone.
- The peaks at 7-8 ppm suggests a para-disubstituted benzene
- This gives the following pieces C6H4, C=O, and 2 different -CH3
- Leads to a suggested molecular formula of C9H10O which gives a MW = 134 g / mol which is 16 short, suggesting an extra O, probably as part of -OCH3 (peak at 3.9 ppm)\
- So, molecular formula of C9H10O2 which gives a MW = 150 g / mol and IHD = 6
- The 13C C=O at 213 ppm is a little high for an ester, so the methoxy group is the second aromatic substituent.
- This gives the structure as:
- Checking the H-nmr, we can see the two uncoupled methyl groups, one deshielded by O, the other slightly deshielded by the C=O and the para-disubstituted benzene.
Cosy predict
SYNTHESIS..........http://www.oc-praktikum.de/nop/en/instructions/pdf/1035_en.pdf
+ |
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+ | ; Side reactions |
13C-NMR
13C-NMR: crude product | |||
75.5 MHz, CDCl3, TMS | |||
delta [ppm] | assignment | ||
25.98 | CH3 acetyl | ||
55.15 | -O-CH3 | ||
113.43 | C3 | ||
130.09 | C1 | ||
130.29 | C2 | ||
163.25 | C4 | ||
196.34 | C=O | ||
76.5-77.5 | CDCl3 | ||
120.8 | C4 (educt anisole) | ||
129.5 | C3 (educt anisole) | ||
13C-NMR: p-Methoxyacetophenone | |||
75.5 MHz, CDCl3, TMS | |||
interactive spectrum | |||
delta [ppm] | assignment | ||
25.98 | CH3 acetyl | ||
55.15 | -O-CH3 | ||
113.43 | C5 | ||
130.09 | C1 | ||
130.29 | C2 | ||
163.25 | C4 | ||
196.34 | C=O | ||
76.5-77.5 | CDCl3 | ||
120.8 | C4 (educt anisole) | ||
129.5 | C3 (educt anisole) | ||
IR
IR: p-Methoxyacetophenone | |||
[KBr, T%, cm-1] | |||
interactive spectrum | |||
[cm-1] | assignment | ||
2964 | arom. C-H valence | ||
2843 | aliph. C-H valence | ||
1669 | C=O valence, ketone | ||
1604 | arom. C=C valence | ||
Operating scheme |
Equipment
round bottom flask 50 mL | reflux condenser | |||
suction filter | suction flask | |||
heatable magnetic stirrer with magnetic stir bar | rotary evaporator | |||
distillation apparatus | oil bath |
Cappadocia Turkey.
Cappadocia - Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Cappadocia
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Mt. Erciyes (3916 m), the highest mountain in Cappadocia
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The town Göreme with rock houses in front of the spectacularly coloured valleys nearby
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A rock-cut temple in Cappadocia
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Cappadocian Greeks in traditional clothing
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