4th EucheMs chemistry congress

wednesday, 29-Aug 2012
s659
chem. Listy 106, s587–s1425 (2012)
Environment and Green Chemistry
Green Chemistry – iii
o - 3 0 0
SurfACtAnt effeCtS on CryStAL Growth of
CLAthrAte hydrAte At interfACe Between
wAter
M. MitArAi 1 , M. KiShiMoto 1 , r. ohMurA 1
1 Keio university, Mechanical Engineering, Yokohama, Japan
This paper reports visual observations of the effect of
surfactants on the clathrate hydrate crystal growth at the interface
of water and cyclopentane. Recently, surfactants are used in gas
pipeline to prevent the hydrate agglomeration which causes flow
channel blockage. On the other hand, surfactants have the effect
of promotion of hydrate formation. These two effects are
apparently contradictory and the physical mechanism of the
surfactant effects is unknown. Surfactants used in the present
study are sorbitan monooleate (Span80), polypropylene glycol
(PPG), and naphthenic acid. These were used at the concentration
of 1000 ppm and 10000 ppm. These are soluble in cyclopentane
liquid phase. Cyclopentane hydrate crystals grew at the interface
of cyclopentane and water to form a polycrystalline layer. We
visually analyzed the individual crystals and classified the
morphology of the hydrate crystals according to the subcooling
(Δ.T ) from the cyclopentane hydrate equilibrium temperature
sub
of atmospheric pressure. It was found that the size of the
individual cyclopentane hydrate crystals decreased with
increasing ΔT . The results showed that the morphology of the
sub
individual cyclopentane hydrate crystals in any surfactant system
is qualitatively similar at a given ΔT . The observations also
sub
showed the three patterns of the behavior of the cyclopentane
hydrate crystal growth depending on ΔT , the chemical species
sub
of the surfactants and their concentration. (i) Crystal growth was
similar to that in pure cyclopentane system without surfactant; (ii)
Surfactants worked as inhibitors and prevented the crystal growth;
and (iii) After the crystals grew at the interface, the hydrate
crystals detached from the interface and fell into the water phase.
These observations indicate that the surfactants have the effect of
inhibitor and change the wettability of hydrate, cyclopentane and
water.
Keywords: clathrate; hydrates; Crystal enginnering; Crystal
growth; Energy transfer;
Green Chemistry – iii
4 th EucheMs chemistry congress
o - 3 0 1
noveL CAtALyStS froM wASte BioMASS:
SyntheSiS, ProPertieS And APPLiCAtion to
the oBtAinMent of BiodieSeL froM ALGAe
e. tAGLiAvini 1 , C. SAMori 2 , d. fABBri 3 , G. fALini 1 ,
P. GALLetti 1 , C. torri 2
1 University of Bologna, Department of Chemistry and Centro
interdipartimentale di ricerca industriale (CIRI), Bologna,
Italy
2 University of Bologna, Centro Interdipartimentale di Ricerca
Industriale, Ravenna, Italy
3 University of Bologna, Department of Chemistry Centro
Interdipartimentale di Ricerca Industriale (CIRI), Ravenna,
Italy
Some important sources of oil, as waste cooking oils and
oils from cultured microalgae, cannot be used for synthesizing
biodiesel by alkaline catalysis because of their high free fatty acids
content. Acids catalysts, homogeneous (e.g. H SO ) or
2 4
heterogeneous (e.g. ion-exchange resins) could represent an
alternative, but they suffer of some important drawbacks. Ion
exchange resins are expensive and do not resist to mechanical
stress; H SO is highly corrosive and require neutralization extra
2 4
step.
Solid acid catalysts, prepared from cheap and easily
available renewable sources represent a more sustainable
alternative. In the present study, new solid acid catalysts have been
prepared from sulfonation of carbonaceous material resulting
from the pyrolysis of sugar beet molasses, the cheap viscous
by-product of the production of sugar, and waste products, like
potato peels. Pyrolysis conditions for molasses and potatoes peel
carbons preparation (temperature and time) was very important
in determining the performances of the catalysts; the best
combination came from pyrolysis at low temperature (420 °C) for
relatively long time (between 8 and 15 h), which ensured a better
stability to the final material. The catalyst resulted to be highly
active in the methanol esterification of fatty acids (100% yield
after 3 h) as well as in the transesterification of acidic vegetable
oils (55–96% yield after 8 h). Finally a “tandem process” using
solid acid molasses catalyst followed by potassium hydroxide in
methanol was developed to effectively convert algal oils
containing high amounts of free fatty acids into biodiesel. [1]
references:
1. Samori C. et al., 2011. ChemSusChem, DOI:
10.1002/cssc.201100822
Keywords: Solid acid catalyst; esterification; biodiesel;
pyrolytic carbon; sulfonation;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc