HOME PAGE * KS3 SCIENCES * GCSE BIOLOGY CHEMISTRY PHYSICS * ADVANCED LEVEL CHEMISTRY

SPECTROSCOPY INDEXES  *  All Advanced Organic Chemistry Notes  *  [SEARCH BOX]

Advanced Organic Chemistry: The H-1 NMR spectrum of propanal

H-1 hydrogen-1 (proton) NMR spectrum of propanal (propionaldehyde)

Doc Brown's Chemistry Advanced Level Pre-University Chemistry Revision Study Notes for UK IB KS5 A/AS GCE advanced A level organic chemistry students US K12 grade 11 grade 12 organic chemistry courses involving molecular spectroscopy analysing H-1 NMR spectra of propanal

low and high resolution H-1 proton nmr spectrum of propanal analysis interpretation of chemical shifts ppm spin spin line splitting diagram H1 1-H nmr for propionaldehyde doc brown's advanced organic chemistry revision notes

TMS is the acronym for tetramethylsilane, formula Si(CH3)4, whose protons are arbitrarily given a chemical shift of 0.0 ppm. This is the 'standard' in 1H NMR spectroscopy and all other proton shifts, called chemical shifts, depend on the individual (electronic) chemical environment of the hydrogen atoms in an organic molecule - propanal here.

The chemical shifts quoted in ppm on the diagram of the H-1 NMR spectrum of propanal represent the peaks of the intensity of the chemical shifts of (which are often groups of split lines at high resolution) AND the relative integrated areas under the peaks gives you the ratio of protons in the different chemical environments of the propanal molecule.

propanal (propionaldehyde),  C3H6O, aldehydes and ketones nomenclature (c) doc b , aldehydes and ketones nomenclature (c) doc b , aldehydes and ketones nomenclature (c) doc b, aldehydes and ketones nomenclature (c) doc b

Interpreting the H-1 NMR spectrum of propanal  (propionaldehyde)

For relatively simple molecules, the low resolution H-1 NMR spectrum of propanal is a good starting point.

The hydrogen atoms (protons) of propanal occupy 3 different chemical environments so that the low resolution NMR spectra should show 3 peaks of different H-1 NMR chemical shifts (diagram above for propanal).

CH3CH2CHO

Note the ratio 3:2:1 of the 3 colours of the protons in the 3 chemically different environments

Although there are 6 hydrogen atoms in the molecule, there only 3 possible chemical environments for the hydrogen atoms in propanal molecule.

The proton ratio 3:2:1 observed, corresponds with the structural formula of propanal.

The high resolution spectrum of propanal

All low and high resolution spectra of propanal show 3 groups of protons and in the ratio expected from the formula of propanal.

The ppm quoted on the diagram represent the peak of resonance intensity for a particular proton group in the molecule of propanal - since the peak' is at the apex of a band of H-1 NMR resonances due to spin - spin coupling field splitting effects - see high resolution notes on propanal below.

So, using the chemical shifts and applying the n+1 rule to propanal

Chemical shift 1.12 ppm CH3 protons (3 protons)

The CH3 proton resonance is split into a 1:2:1 triplet by the CH2 protons.

Evidence for the presence of a CH2 group in the molecule of propanal

Chemical shift 2.47 ppm CH2 protons (2 protons)

The CH2 proton resonance is split from both sides by the CH3 and CH protons to give a 1:4:6:4:1 quintet (4 protons, n+1 = 5).

Evidence, but not exclusively, for the presence of a CH3CH2CH group in the molecule of propanal. You can get the same effect from two CH2 groups of protons.

Chemical shift 9.80 ppm CH proton of CHO group (1 proton)

The lone CH proton resonance is split into a 1:2:1 triplet by the CH2 protons.

Evidence for the presence of a ? group in the molecule of propanal


Number of protons 1H causing splitting Splitting pattern produced from the n+1 rule and the theoretical ratio of line intensities
0 means no splitting             1            
1 creates a doublet           1   1          
2 creates a triplet         1   2   1        
3 creates a quartet       1   3   3   1      
4 creates a quintet     1   4   6   4   1    
5 creates a sextet   1   5   10   10   5   1  
6 creates a septet 1   6   15   20   15   6   1

Key words & phrases: propionaldehyde Interpreting the proton H-1 NMR spectra of propanal, low resolution & high resolution proton nmr spectra of propanal, H-1 nmr spectrum of propanal, understanding the hydrogen-1 nmr spectrum of propanal, explaining the line splitting patterns in the high resolution H-1 nmr spectra of propanal, revising the H-1 nmr spectrum of propanal, proton nmr of propanal, ppm chemical shifts of the H-1 nmr spectrum of propanal, explaining and analyzing spin spin line splitting in the H-1 nmr spectrum, how to construct the diagram of the H-1 nmr spectrum of propanal, how to work out the number of chemically different protons in the structure of the propanal organic molecule, how to analyse the chemical shifts in the hydrogen-1 H-1 proton NMR spectrum of propanal using the n+1 rule to explain the spin - spin coupling ine splitting in the proton nmr spectrum of propanal deducing the nature of the protons from the chemical shifts ppm in the H-1 nmr spectrum of propanal examining the 1H nmr spectrum of  propanal analysing the 1-H nmr spectrum of propanal how do you sketch and interpret the H-1 NMR spectrum of propanal


Links associated with propanal

The chemistry of ALDEHYDES and KETONES revision notes INDEX

H-1 proton NMR spectroscopy index

ALL SPECTROSCOPY INDEXES

All Advanced Organic Chemistry Notes

Use My Google search site box

Email doc b: chem55555@hotmail.com

TOP OF PAGE

 Doc Brown's Chemistry 

*

TOP OF PAGE

latest video game release, latest pop music releases, download free music, latest film releases, latest high street fashion in clothes, fashionable trending in clothing, girls buy clothes, spend a lot of money on clothes, shoes, sweets and chocolates, magazines and make-up. Boys buy food and drink, computer games, DVDs and CDs, girls and boys spend a lot of money on credit for mobile phones, buses and trains to transport them going out. Girls spend a lot of money on clothes color colour preferences in clothes, cool sunglasses, boys  buy expensive things like designer sports clothes and trainers, teenagers save for holidays, clothes, mobile phones, birthday presents and electronic goods, teenage accessories, Favourite style of jeans. A typical girl’s shopping list includes mobile phone credit deals, fashionable quality cool airpods, air pods, fashionable clothes, the most popular favourite sneakers, fancy shoes, sweets, chocolates, magazines, lip moisturizer , lots on make-up, well being, teenage decor decorating their room, teenagers like LED string lantern lights, beauty products for teenagers, denim jackets, scrunchies coolness, fashionable back packs, typical boy’s shopping list includes mobile credit deals, eating out takeaway food and drinks, what teenagers like to buy in clothes, computer games, DVDs, CDs, what teenagers talk about, what teenagers worry about, what teenagers like to do for fun sports, what cool things do teenagers buy, resale websites like eBay Teenager education word cloud how do I apply to university to study biology?, what courses are available at university to study biology?, what grades do I need to get to university to study biology?, how do I apply to university to study chemistry?, what courses are available at university to study chemistry?, what grades do I need to get to university to study chemistry?, how do I apply to university to study physics?, what courses are available at university to study physics?, what grades do I need to get to university to study physics?, how do I apply to university to study biomedical sciences?, what courses are available at university to study biomedical sciences?, what grades do I need to get to university to study biomedical sciences, how do I apply to university to study medicine?, what courses are available at university to study medicine?, what grades do I need to get to university to study medicine?, how do I apply to university to study biochemistry?, what courses are available at university to study biochemistry?, what grades do I need to get to university to study biochemistry?, how do I apply to university to study mathematics?, what courses are available at university to study mathematics?, what grades do I need to get to university to study mathematics?, how do I apply to university to study chemical engineering?, what courses are available at university to study chemical engineering?, what grades do I need to get to university to study chemical engineering?, how do I apply to university to study civil engineering?, what courses are available at university to study civil engineering?, what grades do I need to get to university to study civil engineering?, how do I apply to university to study electrical engineering?, what courses are available at university to study electrical engineering?, what grades do I need to get to university to study electrical engineering?, how do I apply to university to study computer science?, what courses are available at university to study computer science?, what grades do I need to get to university to study computer science?,