1. Abstract
Organogelators are organic molecules that immobilize an
organic solvent. New organogelators were synthesized
by varying alkane chain lengths from C10 to C22 on the
edges of the molecule. Synthesis of the organogelator
involved alkylation of 3,4-dihydroxybenzaldehyde, oxime
formation, reduction to amine, and urea formation. In
order to maintain controlled heating in the alkylation
reaction, a Lab Armor bead bath was used. In the oxime
formation, the ratio of hydroxylamine hydrochloride to the
sodium hydroxide (NaOH) was 3:2, which reduced the
impurities in the oxime product. In the reduction reaction,
the solvent used during the workup was changed from
ethyl acetate to dichloromethane (DCM). The most
effective workup method was to add NaOH (1M) followed
by DCM, which resulted in higher yields of amine.
Byproducts in the amine synthesis resulted in impurities in
the urea, and produced inconsistent critical
concentrations when tested in toluene.
Background
Organogelators are organic molecules that immobilize an
organic solvent. These gelators can achieve this
immobilization by creating a complex matrix that
distributes force applied in one area to the entire
structure. This matrix forms in solution by two
mechanisms:
• Polymerization: monomer converted to polymer
through covalent bonding
• Self-assembly: monomer assembles through van der
Waals forces and hydrogen bonding (non-covalent)
In the self-assembly mechanism, these forces allow for
non-covalent bonding to occur which, in turn create large
aggregates that solidify an organic solvent like toluene.
Gelation is a complex process and is affected by many
other properties like pH, solvent-molecule interactions,
solubility, temperature, and number of hydrogen bonding
units. Additionally since the forces involved are non-
covalent it makes these gels thermoreversibile.
Applications
• Delivery of drugs, nutrients, and vitamins
• Oil spill clean up
• Transport of toxic materials and waste
Hypothesis
Due to van der Waals interactions, an increase in alkyl
chain length should increase gelation efficiency1, which
would decrease the critical concentration.
Synthesis of Bisurea Organogelators Using Varying Alkane Chains
References
1Abdallah, D. J. and Weiss, R. G. (2000), Organogels and Low
Molecular Mass Organic Gelators. Adv. Mater., 12: 1237–1247.
doi: 10.1002/1521-4095(200009)12:17<1237::AID-
ADMA1237>3.0.CO;2-B
2Mehri Kouhkan and Behzad Zeynizadeh, “A New and
Convenient Method for Reduction of Oximes to Amines with
NaBH3CN in the Presence of MoCl5/NaHSO4.times.H2O
System,” Bull. Korean Chem. Soc. 2011.
3Carr, A. J. Thermoreversible Organogelator Research. U.S.
Patent 7332529B2, February 19, 2008.
Saswatha Anireddy, Ethan A. Brem, Jaime J. Cervantes, Woojun Chung, Mayra D. Cuellar,
Divisha S. Eppalapalli, Safa I. Khawaja, Jesus D. Loya Flores, Eyram V. Pleth-Suka, Tamiem
Popal, Hunter L. Sartor, Karisma Y. Sheth, Matthew T. Steidle, America Vallejo, Anastasia Wells,
Andrew J. Carr
Austin College, Chemistry Department, Sherman, TX
Results
Conclusions
In the alkylation reaction, using a Lab Armor bead
bath resulted in more controlled heating compared to
using a mantle or water bath. Temperatures held
between 80-100˚C prevented the formation of
elimination byproducts.
In the oxime formation, an equivalence greater than
1.5 for the hydroxylamine hydrochloride allowed for
the reaction to reach completion in less than an hour
with no trace of starting aldehyde present.
In the reduction of the amine2, there were erratic
yields for each derivative and impurities were in the
product. Changing the workup solvent from ethyl
acetate to DCM improved the isolation of the amine.
However the amine yields were inconsistent, and
minor impurities were detected.
Synthesized ureas, from the impure amines all proved
to be organogelators, with critical gelation
concentrations (CGC) below 1 wt%. The C12 derivative
had a CGC of 0.15%, which was the lowest while all of
the other derivatives are within a factor of ~5. At this
time no observable trends can be established.
Future Research
• Modify the workup of the amine to improve yields
and purity of the amine
• Use purer urea products in gelation tests to
establish trends
• Explore the gelation abilities of the various
derivatives by using different solvents such as,
heptane, dodecane, and gasoline.
Acknowledgements
Dr. Andrew Carr
Janet Boston and Karen Glenn
Austin College Chemistry Department
Derivative
% Yield
CGC
Aldehyde Oxime Amine Urea wt% mM
C10 67.0 47.0 47.0 60.0
C12 89.0 74.0 77.0 61.0 0.15 1.14
C14 94.2 38.0 40.0 29.5 0.3 2.7
C16 79.0 91.9 90.1 87.9 0.45 3.10
C18 92.0 97.6 93.0 94.8 0.32 2.28
C20 69.6 93.3 90.0 25.0 0.76 0.42
C22 86.4 98.0 87.6 81.2 0.24
Table 1. Mass percent yields for the isolated
products from the different reactions. Critical
gelation concentrations (CGC) are reported
in wt% and millimolar.