MG Chem 391 Project Paper Final (1)

Synthesis of Manganese Oxide Nanoparticles Via the Reaction

of Butyric Acid and Potassium Permanganate with Di-Alcohols

Chemistry 391

Milton Garrett III

Connecticut College 14’

Professor Stanton Ching, Project Advisor

Department of Chemistry, Connecticut College

Introduction

Manganese oxides are of particular interest to many scientists for its unique applicable

chemistry in the self assembly of hierarchical nanostructures. The structure and properties of

these manganese oxides allow for the applicable use of battery power technology, toxic waste

removal, and catalytic processes. An interesting feature of these materials is their relatively large

surface area. Manganese is of particular interest because of its ability to be easily oxidized thus

hosting a changing oxidation state. The manganese in the manganese oxide materials also have

the ability to easily change its oxidation state, which is relevant in electrical conductivity. Large

surface area is desirable because it provides more places for catalytic activity to occur and the

exchange of ions to take place. An example would be the toxic waste removal of CO by

conversion to CO2 and NO removal through conversion to NO2. Ions can interchange between

the manganese oxide materials because of its micropourisity.

Stanton Ching, Powerpoint 2010

Figure 1, Removal of CO and conversion to CO2 on manganese oxide surface

The synthesis of inorganic manganese oxide materials yields small microporous

nanoparticles. The chemistry behind the synthesis of these nanoparticles is interesting as there

CO

MnO2

CO2

O2

are many routes to producing manganese oxide products. Routes to synthesizing these materials

are many, some of the most commonly used involve redox reactions with Mn 7+ potassium

permanganate and Mn 2+ salts. Hydrothermal treatment of layered birnessiste structures also

yield porous manganese oxide nanostructures. Another synthetic route is the reaction of a silicon

oxide shell with potassium permanganate and hydrothermal treatment to yield a core shell

consisting both of silicon oxide and manganese oxide. This shell is treated with sodium

hydroxide and silicon etching to yield manganese oxide hollow spheres.1 Studies have proven

that Manganese oxides can also be synthesized by the reduction of Mn 7+ with an organic

reducing agent such as specific carboxylic acids and polyols with sugars resulting in the

formation of sol and gel material. Recent studies of this sol and gel route also indicate that the

reduction of the Mn7+ permanganate with some organic reducing agents can yield microporous

manganese oxides in a “one pot reaction.” Studies have proven success in synthesizing the

favored microporous manganese oxide materials through the reaction of a manganese compound

such as permanganate and an organic reducing agent in the presence of a carboxylic acid . It is

believed that the carboxylic acid directs the formation of manganese oxide tunnel structures .

The synthetic route that will be used in this project involves the formation of manganese oxides

with interesting morphology through a “one-pot” reaction synthesis.

Manganese oxides have unique architectural structures, physical appearances, and

morphology that allows for useful applications. The building blocks for forming most manganese

oxide structures start with a MnO6 octahedron. This octahedron can be assembled by the sharing

of edges of octahedra to form large molecules with different structural arrangements that are

categorized as tunnels. The tunneled manganese oxides are crystallized and the manganese in

1 Ching PPT, Li and co-workers J. Power Sources 2009, 193, 939.

these materials often possess mixed valencies . 2 The tunnels are constructed with single, double

or triple chains of edge sharing MnO6 octahedra to produce structures that resemble tunnels with

a square /rectangular cross-section and sheets of concentric nano-size layers called birnessites .

3The inside of these layered tunnels contain water molecules as well as cations. This unique

physical property is useful as the layered tunnels allow for ion exchange and storage of cations to

stabilize the charge of the manganese oxide material.4Past studies have shown that these

materials yield products with high surface area that come as a result of the aggregation of

particles, interestingly enough to sometimes produce hollow spherical structures. The high

surface area materials are desirable because they are the site for catalytic activity, ion exchange,

and potential for microporousity . The significance of looking for the hollow spheres and a flat

surface is for uniformity in the product at the microscopic level.

Figure 2: Structures of Manganese Oxides, Birnessite, Hollandite (Cryptomelane), and Todorokite respectively.

The objective of this independent study is to test potassium permanganate (KMnO4) with

alcohols, di-alcohols, in the presence of a carboxylic acid using a one-pot reaction mechanism.

The purpose of these experiments are to synthesize nanostructured materials that show

interesting morphology as it relates to small particle size, hollow and spherical architecture, and

2 Angew. Chem. Int. Ed. 2008,

3 Proc.Natl. Sci. Acad. USA 96 (1999), Vol. 96 pp. 3447-3454,

4 Chem. Mater., Vol. 10, No. 10, 1998

potential for high-surface area materials. The manganese oxide materials produced in our lab are

different from those discussed in similar study in that the materials are amorphous and have no

definite layered structure or lattice pattern. A recent study in our lab synthesized useful

manganese oxides using manganese sulfate and permanganate in the presence of a carboxylic

acid through a one-pot route. 5 The most recent work in our lab relating specifically to this

project was the synthesis of manganese oxides using butanol and carboxylic acids. 6

Modifications to the butanol project involved changing the carboxylic acid as well as changing

the alcohol and each of their concentrations in a reaction respectively. The same one-pot

mechanism/idea will be used in this project’s experimental approach using alcohols and di-

alcohols with potassium permanganate in the presence the carboxylic acid, butyric acid (BA),

maleic acid (MA), Glutaric Acid (GA), Pimelic Acid (PA), and Succinic Acid (SA) .

Synthesizing manganese oxides using dialcohols would be of interest in this project because of

the two hydroxyl functional groups in the compound. One could assume that the presence of two

hydroxyl functional groups would yield useful manganese oxide products. The basis for this

rationale would be because of recent success in our lab in synthesizing desirable manganese

oxides using butanol as a reducing agent.

Experimental Section

The general/standard procedure for the synthesis of manganese oxides in the Ching lab

lab involves a reaction between MnSO4 and KMnO4 in the presence of a carboxylic acid (butyric

acid). To start, 1 mmol (.254 grams) of MnSO4 is dissolved in a beaker filled of 25 mL of

distilled water. Then, 2.3 mL (24mmol) of butyric acid is added to MnSO4 solution and is stirred

5 Chem. Commun., 2011 47,8286-8288)

6 Ian Ritcher and Kathryn Tutunjian (Unpublished Work)

vigorously with a magnetic stirrer. One mmol of KMnO4 (.158 grams) is added to a beaker of 25

mL of distilled water and stirred vigorously to dissolve any solid permanganate. The

permanganate solution is added to the manganese sulfate solution and the mixture of both

solutions is stirred vigorously. A brown solid is formed and the mixture is stirred for 15 minutes.

The solid was isolated by filtration, washed three times, then dried at 110 oC.

Generally, manganese oxide materials are analyzed through characterization imaging,

determination of manganese content in the samples, and testing for surface area.

Characterization of manganese oxide is done through Scanning Electron Microscopy (SEM),

Transmission Electron Microscopy (TEM), Thermogravimetric Spectrospescopy, (TGA), and

Atomic Absorption (AA). Determining the content of manganese in the samples are done by

performing oxidation states and surface area analysis is done by Brunauer-Emmet Teller (BET)

analysis . TGA, SEM, and TEM were performed on manganese oxide materials synthesized in

this specific project. Analysis of manganese oxides materials via reactions with butanol have

calculated the oxidation state of manganese in the materials to between 3+ and 4 + .

In the reactions of this project, KMnO4 is reacted with an alcohol/dialcohols in the

presence of a carboxylic acid. A series of reactions with butyric acid and the following alcohols

were performed: allyl-alcohol, 1,4 -butanediol, 1,8- octanediol. Three experiments were

performed with 1,4 –butanediol. The detailed synthesis for each reaction involving 1,4-

butanediol and each trial is described in the table below in Figure 3.

1,4 -Butanediol with BA

1,4 -Butanediol

Moles of KMn04

Carboxylic Acid

Moles of Carboxylic Acid

Moles of Alcohol

Volume of Distilled H20

Reaction

Time *

Mole Ratio/ Unique OBS

Trial 1 1mmol

.158g

Butyric Acid

24 mmol

(2.3mL)

6mmol

(.55mL)

50 mL Fast Moles OH: Mn = 6:1

Trial 2 1 mmol

.158g

Butyric Acid

24mmol

(2.3 mL)

12mmol

(1.1mL)

50 mL Very slow

Let stir over weekend

Moles OH: Mn = 12:1

Trial 3 1 mmol

.158g

Butyric Acid

24mmol

(2.3 mL)

24mmol

(2.2mL)

50 mL Normal Moles OH: Mn = 24:1

Figure 3, 1,4 -Butanediol with BA *Normal reaction times occur between 9-15 minutes

1,8 -Octanediol with BA

Seven experiments were performed with 1-8 octanediol. The detailed synthesis for each

reaction and each trial is described in the table below in Figure 4.

1,8 -Octanediol

Moles of KMn04

Carboxylic Acid


Moles of Alcohol


Reaction

Time *

Unique OBS/ Mole ratio

Trial 1 1mmol

.158g

Butyric Acid

24 mmol

(2.3mL)

6mmol

(.885grams)

50 mL Fast

Moles OH: Mn = 6:1

Trial 2 1 mmol

.158g

Butyric Acid

12mmol

(1.1 mL)

6 mmol

(.885grams)

75mL Normal Moles OH: Mn = 6:1

Trial 3 1 mmol

.158g

Butyric Acid

6 mmol

(.55mL)

12mmol

(1.58 grams)


Trial 4 1 mmol

.158g

Butyric Acid

6mmol

(.55mL)

12mmol

(1.58 grams)

40ml Normal Moles OH: Mn = 12:1

Trial 5 1 mmol

.158g

Butyric Acid

12mmol

(1.1mL)

12mmol

(1.58 grams)


Trial 6 1 mmol

.158g

Butyric Acid

12mmol

(1.1 mL)

12mmol

(1.58 grams)

75 mL Normal Moles OH: Mn =12:1

Trial 7

Control

1mmol

.158g

None None 6 mmol

.885grams


Figure 4, 1,8 -Octanediol with BA *Normal reaction times occur between 9-15 minutes

Seven reactions were done with allyl alcohol. The detailed synthesis for each reaction and

each trial is described in the table below in figure 5

Allyl Alcohol

Moles of KMn04

Carboxylic Acid


Moles of Alcohol


Reaction

Time *

Mole Ratio/ Unique OBS

Trial 1 1mmol

.158g

Butyric Acid 24 mmol

(2.3mL)

2mmol

.14mL)


Trial 2 2 mmol

.316g


(2.3mL)

1 mmol

(.07mL)


Trial 3 4 mmol

.632g


(2.3mL)

2mmol

(.14mL


Trial 4 2 mmol

.316g


(2.3mL)

2mmol

(.14mL)


Trial 5 1 mmol

.158g

Butyric Acid 24mmol (2.3mL)

1mmol

(.07mL)


Trial 6 1 mmol

.158g

Butyric Acid 24mmol (2.3mL)

.5 mmol

(.035mL)

50 mL Normal Moles OH: Mn = .5 : 1

Trial 7

Control

1mmol

.158

None None 1 mmol

(.07mL)

50mL Normal Moles OH: Mn =1:1

Slow reaction

Figure 5, Allyl Alcohol with Butyric Acid *Normal reaction times occur between 9-15 minutes

Butanol with varying Dicarboxylic acids

Butanol was reacted with KMnO4 and the following carboxylic acids: pimelic acid (PA),

succinic acid (SA), maleic acid (MA), glutaric acid (GA). The detailed synthesis for each

reaction and each trial is described in the table below in figure 6

Butonal

Moles of KMn04

Carboxylic Acid


Moles of Alcohol


Reaction

Time *

Unique OBS

Trial 1 1mmol

.158g

Glutaric Acid 12mmol

(1.58 grams)

12mmol

(1.1mL)

50 mL Normal

Trial 2 1 mmol

.158g

Maleic Acid 12mmol

(1.41 grams)

12mmol

(1.1mL)

50 mL Very fast Mn 2+ solution quickly,

brown, to yellow, to

clear color in seconds

Trial 3 1 mmol

.158g

Pimelic Acid 12mmol

(1.92 grams)

12mmol

(1.1mL)

50 mL Normal

Trial 4 1 mmol

.158g

Succinnic Acid 12mmol

(1.41 grams)

12mmol

(1.1mL)

50 mL Normal

Figure 6, Butanol with Varying Carboxylic Acids *Normal reaction times occur between 9-15 minutes

Results and Discussion

Results indicate that the series of experiments with 1,4 -butanediol aren’t as effective in

reproducing the desired manganese oxide. figure 7 shows SEM characterization of the 1,4 -

butanediol experiment that yield some small spherical nanostructures. Figure 7 shows edges of

the spheres to overlap. Although figure 7shows a lack of uniformity in the product and

disproportionate spherical nanoparticles , because of its nanostructure this sample would be a

good candidate for BET analysis in the future. Most of the reactions with 1,4 -butanediol

occurred quickly and the reaction took place within 8-15 minutes.

Figure 7. 1,4-Butanediol with Butyric Acid , Trial 2 (1mmol KMnO4 12 mmol of Alcohol , 24 mmol of BA)

Butanol

The butanol series of reactions did not produce interesting results at all as many of the

characterization images shows the morphology of these products not to be useful. Figure 8 shows

a sample of Pimelic acid (PA), trial 3 in the butanol experiments, with a surface of large non-

uniformed particles. The surface of the large particles appear to be rough and non-concentric.

The observations of this sample indicate that there is an absence of visible hollow spheres, thus

showing that there is no potential for surface area in this material. The butanol reaction with

maleic acid (Trial 2) yielded a result that was observed as a solution of manganese 2+ as the

product. The color of this solution changed from brown to yellow, to clear in a matter of a few

seconds.

Figure 8. Butanol with Pimelic acid (Trial 3, 12 mmol PA, 12 mmol Butanol,1mmol KMnO4)

1,8-Octanediol

Materials synthesized from 1,8- octanediol yielded products with spherical and hollow

morphology. Figure 9 is a SEM image from trial 1of the 1,8-octanediol experiments that shows

nanoparticles that are uniformed and spherical. This reaction was reproduced however,

characterization of the reproduced sample did not show the same features in SEM

characterization as the original sample; hence it was noted that this experiment could not be

routinely reproduced.

Figure 9. 1,8-Octanediol with Butyric Acid , Trial 1, (1mmol KMnO4 , 6 mmol of Alcohol , 24 mmol of BA)

The reaction for trial 1 was fast and yielded interesting results. From the results one can conclude

that the excess of butyric acid (24 mmol) with 1,8-octanediol (6mmol) in the presence of

(1mmol) permanganate yields small spherical nanostructures products. Results indicate that

increasing the concentration of 1,8-octanediol had no affect on morphology of the sample. Trials

3 and 4 show the comparison in synthetic conditions for increasing the concentration of 1,8 -

octanediol.

The SEM images of trial three in this experiment show manganese oxides that are made

up of small spheres. The SEM image of trial 3 is shown in figure 10. The size of these particular

spherical nanoparticles appear to be much smaller than the nanoparticles produced in other

experiments. The surface of this product is uniform, hence these products would be a good

candidate for BET surface area analysis.

Figure 10, 1,8 -Octanediol (Trial 3, 6mmol BA, 12 mmol 1,8-octanediol, 1mmol KMnO4)

TGA analysis of trial 3 is shown in figure 11. The analysis shows a significant amount of

product weight loss at a rather low temperature. A sharp decline in weight loss occurs at around

220 oC ; weight loss at this temperature may be due to the burning of hydrocarbons in the

material.

Figure 11, TGA Analysis of Trial 3

Figure 12 shows SEM characterization of the control for this experiment. The images

from the control indicate that without the presence of butyric acid, the surface of the manganese

oxide materials would not be spherical or small in particle size.

Figure 12, 1,8 -Octanediol (Trial, 6 mmol 1,8-octanediol , 1mmol KMnO4, no BA )

Possible reasons why there are differences between materials of the 1,4- butanediol and

1,8 -octanediol materials is because of the number of methylene groups in between in each

alcohol. Based upon characterization results, 1,8 –octanediol yields products with better

morphology.

Allyl alcohol

Allyl alcohol is very reactive and has the potential to be a dangerously flammable

reactant, so the concentration used in the series of reactions was very low. The experiments with

allyl alcohol produced interesting results, however the design of the experiment could have had a

better systemic approach. Reasons why allyl alcohol produced such interesting results may be

because of the manganese having possible reactivity with the double bond reacting. Figure 13

shows trial 5 in the experiment, 1mmol KMnO4, 1mmol of allyl alcohol, and 24 mmol of BA.

Figure13. Allyl Alcohol Trial 5 (1 mmol of Alcohol , 24 mmol BA, 1mmol KMnO4 in 50 mL of water)

TGA analysis was done on trial 5 and is shown in figure 14. There is a gradual decrease

in product weight until about 480 oC; this loss of weight may be due to the loss of water and

lattice oxygen in the material. Similar projects in our lab have shown the thermal stability of

manganese oxides materials using MnSO4 and KMnO4 to resemble the TGA curve depicted in

figure 14.

Figure 14, TGA Analysis of Trial 5

Figure 15 shows the reaction of trial 4 in which 2 mmol of permanganate react with

2 mmol allyl alcohol, and 24 mmol of BA. The manganese oxides in this reaction show the best

morphology as the surface shown is made up of many uniform nanoparticles that also appear to

be hollow.

Figure15. Allyl alcohol with butyric acid. (Trial 4, 2mmol of KMnO4 , 2mmol of allyl alcohol, )

Figure 16 shows a TEM image of trial 4, the surface is composed of thin fibrous

nanaoparticles definitely useful for applications of surface area. Under high magnification, the

surface of this sample looks hollow and the shape of the particles on the surface look fibrous;

hence indicating small uniform manganese oxide nanoparticles. This sample is a good

candidate for BET surface area analysis.

Figure 16. Allyl alcohol with butyric acid. (Trial 4, 2mmol of KMnO4 , 2mmol of allyl alcohol )

Figure 17 shows an SEM of allyl alcohol with no butyric acid (Trial 7). From this image,

one can deduce that without the presence of butyric acid, the surface of the manganese oxide

materials would not be spherical or small in particle size.

Figure 17. Allyl alcohol with butyric acid (Trial 4, 1mmol of KMnO4 , 1mmol of allyl alcohol, no BA)

Conclusion

Results from this project support the argument that the presence of a carboxylic acid

plays a huge role in directing the formation of hierarchical manganese oxide nanostructures. In

the experiments with 1,8-octanediol and allyl alcohol, characterization of the control for both

experiments lack small uniform nanoparticles in their morphology, thus supporting the argument

that carboxylic direct the formation of hollow spherical manganese oxides. Results from the

butanol experiments indicate that the selection of an appropriate carboxylic acid and relative

concentration play a huge factor in determining the outcome of the product. In comparison to

recent research with butanol, the dicarboxylic acids used in this experiment produced worse

results than a carboxylic acid such as butyric acid. The results of this project study indicate that

the smaller more uniform manganese oxide particles occur in di-alcohol reactions that have

more methylene groups in between each alcohol functional group. Comparison between the

characterization results of 1,8-octanediol and 1,4-butanediol support this experimental

hypothesis.

In the 1,8-octanediol reaction , the best results occurred when the concentration of

alcohol was between 6 and 12 mmols. Allyl alcohol yielded manganese oxides with the most

interesting architecture even at a substantially low concentration in comparison to the 25x mmol

excess amount of carboxylic acid. The success of using di-alcohols in this project is useful to

our laboratory research because characterization of these samples indicate the product’s potential

for high surface area and catalytic activity. Experiments with allyl alcohol show similarly

interesting morphology in reactions where 1mmol and 2mmol of potassium permanganate were

reacted. Future work on reactions with alcohol might include trying different experimental

approaches with 1-8 octanediol and allyl alcohol. Perhaps, increasing the amount of allyl alcohol

and adjusting the synthetic conditions would yield samples with even more interesting results.

As for the butanol series, perhaps trying another carboxylic acid, or decreasing the amount of the

carboxylic acid will affect the morphology of the samples.

Reference

1 Ching PowerPoint, Li and co-workers J. Power Sources 2009, 193, 939.

2 A Core-Corona Hierarchical Manganese Oxide and its Formation by an

Aqueous Soft Chemistry Mechanism, David Portehault, Sophie Cassaignon, Nadine

Emmanuel Baudrin, and Jean Pierre Jolivet, www. Angewandte.org , Angew.

Chem. Int. Ed., 47, 6441-6444 , 2008

3 Manganese Oxide minerals: Crystal structures and economic and environmental

significance, Jeffery E.Post, Proc.Natl. Sci. Acad. USA 96 (1999), Vol. 96 pp.

3447-3454, March 1999

4 A Review of Porous Manganese Oxide Materials Stephanie L. Brock, Niangoa

Duan, Zheng, Rong Tian, Oscar Giraldo, Hua Zhou, and Steven Suith, Department

of Chemistry, Institute of Materials Science, and Department of Chemical

Engineering, University of Connecticut, Storrs, Connecticut 06269-4060,Suib

Chem. Mater., Vol. 10, No. 10, 1998 ,U-60,

5 Self –assembly of manganese oxide nanoparticles and hollow spheres. Catalytic

activity in carbon monoxide oxidation. Stanton Ching , David A. Kritz, Kurt M.

Luthy, Eric C. Njagi, Steven L. Suib ,Chem. Commun., 2011 47,8286-8288) Royal

Society of Chemistry 2011

6 Butanol and Carboxylic acid Synthesis of Manganese Oxides, Connecticut

College, Ching Lab, Ian Ritcher and Kathryn Tutunjian, (Unpublished Work) 2011

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MG Chem 391 Project Paper Final (1)