Download Synthesisof Cumene (Isopropyl Benzene) from Rosin Oil Through

Synthesisof Cumene (Isopropyl Benzene) from Rosin Oil Through Cracking
And Dehydrogenation
Savitri1, Mohammad Nasikin2, Nino Rinaldi1, Dadi Ramdani1
1
Indonesian Institute of Sciences, Research Centre for Chemistry
Departement of Chemical Engineering, Faculty of Engineering, Indonesian University
2
Abstract
Cumene has been synthesized from rosin oil through cracking and dehydrogenation reactions
using modified HZSM-5 catalyst. The research has successfully modified the zeolite-based
solid acid catalyst by adding Cu-Ni and Ni-Mo metal as promoter. Modified HZSM-5
catalysts were characterized using gravimetry and FTIR-pyridine method, the result shown
that the acidity of the catalyst was decreased. Catalyst activity test for cracking and
dehydrogenation reactions were carried out to obtain condition of cumene prodution. The
final products were analyzed using FTIR and GC-MS. Cu-Ni/HZSM-5catalyst was suitable
for the cracking-dehydrogenation reactions of rosin oil to produce cumene with process
conditions of 30 bar and 450oC
Keywords: cumene;rosin oil; cracking; dehydrogenation, modified HZSM-5, acidity.
Abstrak
Telah dibuat senyawa cumene dari minyak gondorukem (rosin oil) melalui reaksi “Cracking”
dan dehidrogenasi menggunakan katalis HZSM-5 termodifikasi. Penelitian ini berhasil
melakukan modifikasi terhadap katalis asam padat berbasis zeolit dengan menambahkan
promotor logam Cu-Ni dan Ni-Mo. Katalis HZSM-5 termodifikasi dikarakterisasi
menggunakan metoda gravimetri dan FTIR-pyridine yang menunjukkan terjadi penurunan
keasaman katalis.Uji aktivitas katalis untuk reaksi “Cracking”dan dehidrogenasi dilakukan
untuk mendapatkan kondisi proses yang mengarah kepada produk senyawa cumene. Analisa
produk akhir menggunakan GC-MS. Katalis Cu-Ni/HZSM-5 mampu melakukan reaksi
“Cracking”-dehidrogenasi gondorukem sehingga menghasilkan cumene . Proses tersebut
terjadi pada kondisi 30 bar dan 450o C.
Kata Kunci : cumene, minyak gondorukem, perengkahan, dehidrogenasi, HZSM-5
termodifikasi, keasaman.
1
INTRODUCTION
Cumeneorisopropylbenzeneis
usuallysynthesizedfromalkylationof
benzenewithisopropylalcoholderivedfrom
petroleum.Butpetroleum
is
un-renewable
resourcewhich isdwindlingreserves every year.Cumene can be used as additive for raising the
octane number of gasoline.[1]
The consumptionof petroleumincrease every year due to lower productionof
nationalpetroleumexplorationactivities,which isencouragethe search foralternativesourcesof
raw
materialsthatcanbe
processedintocumene.
resourceisvegetableoil.Vegetableoilisgenerallycomposed
The
oftriglyceridesandfree
fattyacidscontaininghydrocarbon compounds whichis almost similar with chemical structure
of petroleum.
Severalstudies
have
beenconductedtoconvertvegetable
oils
intomore
valuableproducts,for example the convertion of vegetable oilinto methyl ester. The vegetable
oilwasobtainedfrompalm,coconut,soybean, jathropaandothers. Butthe vegetable oilisussually
usedmostly asedible oil, so it bring the controvertion with theissue of foodsouverignity.
Thereforetheproducts ofthe forestindustry residuessuch aspine resin, gumrosin, ortalloil (byproductof
paperindustry)
were
studied
forthe
possibilitytobe
convertedinto
fuelorotherchemicalproducts.[2]
Rosin oil is made up of a number of differentditerpenoid (resin) acids, diterpene
alcohols, aldehydesand hydrocarbons.All the resin acids have the same basicstructure and
would result in the same product oncomplete hydrogenation with no cleavage of bonds.
Mostly rosin oil is exported as raw material according to this research.[3]
Therosinoil used as a raw material for this workcontains resin acid, turpentine and other
chemical compound.Table 1 shown neoabietic acid, dehydroabietic acid and abietic acid are
the main composition (35,55 %, 17,15 % and 17,08 %) in rosin oil. Meanwhile Figure 1
shows the chemical structure of major component in rosin oil.
Table 1.Major component of Rosin Oil [GC-MS analysist]
Compound
α-pinene (turpentine)
camphene
Delta-3-carene
limonene
borneol
Neoabietic acid
2
(%)
5,47
4,42
5,10
8,73
6,50
35,55
Dehydroabietic acid
Abietic acid
H
H
O
HO
17,15
17,08
O
O
abietic acid
HO
HO
dehydroabietic acid
neoabietic acid
Figure1.Chemical structures of major components in rosin oil.
The previous research on rosin oil shown that, the distillate of rosin oil was succesfully
converted into methyl ester, and the product was suitable as fuel for bio-diesel and gasoline.[4]
Another studyon fuel generation was using rosin oil as alternative source by cracking catalytic
processes.The catalysts were HZSM-5 and Ni-Mo or Co-Mo commercial.[2]
On
the
other
hand,
a
researchonthe
hydrogenation/dehydrogenationprocess
ofrosinoilusingNi/Y-zeolite catalysthas beendone.The resultwas p-cymene as intermediate
product (p-cymene has similarity chemical structures with cumene) and toluene was the final
product.[5]Latelyresearch on bio-diesel production[6], was made by the transformation of tall
oil into a bio-diesel in hydrotreating process using Ni-Mo/Al2O3 and Ni-W/Al2O3-zeolite
catalyst.Another study on the convertion of tall oil[7]were pyrolysis of tall oil rosin and tall oil
fatty acid. The end productswere aromatic hydrocarbon compounds namely benzene, toluene,
cumene, indan, naphthalene, phenanthrene and phenol.
The idea for this work is based on the previous researches. The question is, Is the major
component in rosin oil can be converted into another chemical compound such as cumene
(isopropyl benzene). Using HZSM-5 as the heterogeneous solid acid, will be modified with
metal promoterssuch as cuprum-nickel and nickel-molybdenum to reduce the acidity or the
acid strength. The solid catalyst with suitable acidity could crack and dehydrogenate rosin oil
into cumene as the final product. The modified catalysts would be analyzed forits acidity
using gravimetry and FTIR-pyridine method. Thefinalproducts will be determinedusingGCMS.
MATERIALS AND METHODS
3
Preparation of Catalysts
Thecatalystsusedforthe experimentswere comercial zeolite (HZSM-5) which is
modified using metal promoterNickel (Ni), cuprum (Cu) and molybdenum (Mo). CuNi/HZSM-5 and Ni-Mo/HZSM-5 were a dual functioncatalystswhich are common in a
cracking and hydrogenation/dehydrogenationreactionunitofrefinedcrudeoil. HZSM-5 isanacid
mineral
that
can
promote
cracking
reaction,
while
Cu,
Ni
and
Mo
are
neededtopromotedehydrogenationafterthe cracking.[8]
The comercial zeolite (HZSM-5) CBV 2020E typewith mole ratio of SiO2/Al2O3 = 30,
Na2O weight 0,1% and surfaceareaof 400 m2/gram. HZSM-5 wereanalyzedwith XRF and
thecompositionwere: 0,24% ZnO; 0,22% TiO2; MgO< 0,001%; 0,23% BaO; Na2O < 0,001%;
0,49% Fe2O3; 0,005% CaO; 0,073% K2O; 89,65% SiO2 and4,66% Al2O3.
Cuprum
and
nickelwereimpregnatedtothe
HZSM-5
byaddingCu
(NO3)2.3H2O
andNi(NO3)2.6H2Oaqueoussolution.To obtain Cu-Ni/HZSM-5 catalyst, nickel loading was
5% and cuprumloadingwas 5%weightas same as the nickel loading. After each impregnation,
the catalyst was dried at 100°C over night and later than calcified at 500°C for 5 hours. Nickel
and molybdenum were impregnated to HZSM-5 by addingNi(NO3)2.6H2O and(NH4)
Mo7.O24.4H2Oaquaeoussolution. To obtain Ni-Mo/HZSM-5, molybdenum loading was 15%
weight of MoO3and nickel loading was 5% weight of NiO. Later than, the catalyst had the
same treatment as the preparation of Cu-Ni/HZSM-5 catalyst.The modified HZSM-5catalysts
were determined using gravimetry and FTIR-pyridine method to observe the acidity and
Brönsted-Lewis acid sites.
Cracking and Dehydrogenation
Cracking and dehydrogenationreactions of rosinoilwerecarriedout in an autoclave
batchreactorwithpressure of 30 – 60 bar and temperature of 400 – 450º C.In the experiment,
Rosinoilwasweighed
50
gramandcatalystwas
1
%
(w/w)
fromrosinoil.
Thetwocomponentswereput in the reactor and thetemperaturewasadjusted at 400º C.
Theduration
of
cracking
and
dehydrogenation
processes
was
1
hourafterthereactiontemperature achieved. The final productwascharacterized usingFTIR
andGC-MS.
The analysis of chemical compound and the chemical structure of rosin oil and the
product usingAgilent Technologies 6890 Gas Chromatograph 5973 Mass Selective
Detectorwith data process of Chemstation which is equipped with coloumnkapiler HP Ultra 2
(17 m x 0.25 mm id. and film thickness was 0.25 μm).
4
RESULT AND DISCUSSION
Acidity properties of modified HZSM-5
The acidity properties of HZSM-5 and the modified HZSM-5 were analyzed using
gravimetry-pyridine adsorption method.The method was counting the adsorption of pyridine
in the surface of catalyst. The amount of pyridine which adsorbed was observed by
gravimetry method. The results were the acid amount with assumption that the size of
pyridine molecule was large enough which can be adsorbed at the surface of catalysts.[9]Acid
amount of the catalysts were shown at table 2.
Table2. Acid amount of modified HZSM-5
Catalyst
HZSM-5
Acid amount (mmol/gram)
0,41
Ni/HZSM-5
0,24
Ni-Mo/HZSM-5
0,23
Cu-Ni/HZSM-5
0,23
As we can see in the Table 2. The HZSM-5 had the highest acid amount.The
incorporation of nickel (Ni/HZSM-5) decreased the acid amount of HZSM-5. The adding of
another metal promoter (Cu-Ni/HZSM-5 and Ni-Mo/HZSM-5) has reduce the amount of the
acid of modified HZSM-5 lower. The reduction of acid amount after promoter metals
impregnation due to the promotersimpregnation. The promotor metals were impregnated at
the surface of HZSM-5 successfully. The first idea was to modified HZSM-5 catalyst to
minimize the acidity.Therefore, the modified catalysts could carry out the cracking and
dehydrogenation of rosin oil to produce cumene. The previous researches
[5,10]
produced
several hydrocarbon components such as phenanthrene, naphthalene, cumene, toluene,
benzene, and pentene using the same method. The lower acidity of modified catalysts could
stop cracking and dehydrogenation of rosin oil and resulting cumene as the final product
respectively.
The FTIR analysis of catalysts (Brönsted and Lewis acid site)
To observe Brönsted and Lewis acid sitesof modified HZSM-5 qualitatively were
using FTIR. The acid sites were observed at wave numbers of 4000 – 400 cm-1. The Lewis
acid site was shown at 1450 cm-1.[11]The pyridine ions were attached with Lewis acid on
catalysts. The infrared spectra of modified catalysts were recorded for the analysisof Brönsted
and Lewis acid sites with wave numbersbetween 1700- 1400 cm-1. The assignment of
5
frequencies for pyridine adsorbed on Brönsted and Lewis acid sites aresummarized[12]inTable
3.
Table3. Assignment of frequencies for pyridine adsorbed on Brönsted and Lewis acid
sites.[12]
Wave number (cm-1)
Assignment
1440
Hydrogen-bonded pyridine.
1450
Pyridine molecules adsorbed on Lewis acid sites.
1490
Hydrogen-bonded pyridine and pyridine molecules adsorbed
on Brönsted and Lewis acid sites.
1545, 1620 – 1650
Pyridine molecules adsorbed on Brönsted acid sites.
1620 - 1630
Pyridine molecules adsorbed on Lewis acid sites.
The FTIR spectrum of pyridine adsorption on HZSM-5 and modified HZSM-5 are
shown in figure 2. As we can see from figure 2 (1), HZSM-5catalysthas both the acid sites
(Brönsted and Lewis acid sites), one Lewis acid site is shown at wave number 1450 cm-1, and
the Brönsted acid sites are shown at wave number 1545 and 1640 cm-1. This catalyst also has
hydrogen-bonded pyridine and pyridine molecules adsorbed on Brönsted and Lewis acid
sites[12]at 1490 cm-1. But after HZSM-5 was impregnated with nickel metal, the acid sites of
catalyst (Ni/HZSM-5)was changed. Ni/HZSM-5 catalyst, figure 2 (2) only has two Lewis acid
sites at 1460 cm-1 (the wave number is shifted from 1450 to 1460 cm-1) and 1620 cm-1, the
Brönsted acid sites are not seen at all.
Brönsted
Lewis
Brönsted dan Lewis
(4)
(1) HZSM-5 catalyst
(2) Ni/HZSM-5
%T
(3)
(4) Ni-Mo/HZSM-5
(2)
(1)
1700
(3) Cu-Ni/HZSM-5
1600
1500
1400
Wave number (cm-1)
Figure 2.FTIR spectra of catalysts
6
1300
Then after Ni/HZSM-5 was impregnated with cuprum metal, the acid sites of catalyst
(Cu-Ni/HZSM-5) was changed again. The Brönsted and Lewis acid sites appeared again at
wave number 1490 cm-1, although the spectrum peak was not too sharp if it compared with
the spectrum peak of HZSM-5. Cu-Ni/HZSM-5 catalyst,figure 2(3) has two Lewis acid sites
at wave number 1630 cm-1 and 1450 cm-1. Meanwhile Brönsted acid sites is shown at wave
number 1640 cm-1 although the spectrum peak is almost broad and not sharp enough as well
as the HZSM-5. When the metal promoters which were impregnated into HZSM-5 were
nickel and molybdate (Ni-Mo/HZSM-5), the acid sites was changed again. It only has one
Lewis acid site at wave number 1450 cm-1 and one Brönsted acid site at 1630 cm-1. But the
spectrum peak of Cu-Ni/HZSM-5 at wave number 1450 cm-1 is the sharpest among the
HZSM-5 (1), Ni/HZSM-5 (2) and Ni-Mo/HZSM-5 (4). It is assumed that the type of metal
promoters influence acidity of HZSM-5 catalyst. It has something to do with the framework,
pore size and morphology of the HZSM-5 and the modified HZSM-5.[12]The most important
thing is the impregnation of metals can reduce acidity or acid strength of HZSM-5 and
resulting suitable acid catalyst.Therefore rosin oil can be converted into cumene by cracking
and dehydrogenation reaction. After the modified catalysts were tested for the activities then
we can see the connection impregnation process to produce solid acid catalyst with cracking
and dehydrogenation reaction of rosin oil.
The GC-MS analysis of rosin oil and products
The rosin oil and product were analysized using GC-MS. The chromatogram GC-MS
of rosin oil and product are shown in figure 3 and 4.
A b u n d a n c e
T IC : S 2 _ U L .D
7 3 . 17 46 . 1 0
7 7 .4 0
9 0 0 0 0 0
8 0 0 0 0 0
7 8 .7 4
7 0 0 0 0 0
6 0 0 0 0 0
7 8 .3 8
7 5 .5 3
2 0 .4 9
5 0 0 0 0 0
4 0 0 0 0 0
7 8 .5 5
2 4 .4 7
77 55 .. 01 49
7 8 .2 4
2 1 .3 2
7 5 .9 0
2 5 .4 1
3 3 .7 7
3 0 0 0 0 0
7 3 .8 8
3 2 .6 6
6 6 .1 6
2 0 0 0 0 0
7 2 .0 7
2 5 . 1 29 8 . 5 3
1 0 0 0 0 0
1 5 .0 0 2 0 .0 0 2 5 .0 0 3 0 .0 0 3 5 .0 0 4 0 .0 0 4 5 .0 0 5 0 .0 0 5 5 .0 0 6 0 .0 0 6 5 .0 0 7 0 .0 0 7 5 .0 0 8 0 .0 0
T im e - - >
Figure3.GC-MS of rosinoilbeforereaction.
7
In figure 3, the main components in raw material are shown at retention time between
20,49 – 33,7 minute and 66,16 – 78,74 minute. The major component of rosin oil are shown at
table 1.
At figure 4, rosinoilwascracked and dehydrogenatedusing HZSM-5 catalyst(weighed
1% of raw material)withpressure of 60 bar and temperatura of 400º C. There are severalnew
component are shown at retention time of 24,40 – 53,51 minute.
Abundance
T IC : S 7 .D
5 0 .7 8
7000000
5 3 .5 1
6000000
5000000
4 7 .9 7
2 9 .3 2
4000000
4 54.66 .37 43 9 . 4 0
4 3 . 9 3 4 74. 87 .38 6
4 8 .9 4
3000000
1 7 .5 8
2000000
1 1 .8 1
1000000
1 0 .0 0
4 6 . 8 745 90 5..911511.24.94 4
4 1 . 3 4 4 44.58 .59 4444999..1.36913
4 2 . 8 24 64. 17 8. 5 2
3 7 .1 9
5 4 .2 4
3 4 . 33036 7. 7. 40 3 4 14. 62 49. 94 3. 34 346 47.4457.8251..80163
5 05.52892.750. 65 9
4422. 2. 689
3 23 .37 .27 5
2 7 .8 1
2 0 .7 6
1 5 .2 5
1 51. 63 .15 1
1 7 . 6 8 2 2 .2643. 4 0
1 5 .0 0
2 0 .0 0
2 5 .0 0
3 0 .0 0
3 5 .0 0
4 0 .0 0
4 5 .0 0
5 0 .0 0
5 5 .0 0
6 0 .0 0
T im e -->
Figure 3.GC-MS of productafterreactionusing HZSM-5catalyst
Fromthechromatograms
of
theseprocess,
almostall
rosinoilwasconvertedintoanothercompounds.
neoabieticacidanddehydroabieticacid)are
camphene,
delta-3-carene,
of
component
of
Theresinacids(abieticacid,
notfound
in
limonene
productsanylonger.
Turpentine,
andborneolarenotseeneither.
Cumenewasformedalthoughonly in relatively small concentration. Themajorcomponent of
end productisphenanthrene.
Therosinoilwascracked and dehydrogenatedusingNi/HZSM-5, Cu-Ni/HZSM-5 and
Ni-Mo/HZSM-5catalystswiththesamecondition of thefirstprocess.Thewholecomponents of
products are shown at table4.
Table 4.GC-MS of products from cracking – dehydrogenation reactions
No.
Compound
HZSM-5 Ni/HZSM-5 Cu-Ni/HZSM-5 Ni-Mo/HZSM-5
1.
2.
3.
4.
Pentane
Toluene
p-xylene
Cumene
%
5,47
0,89
0,27
0,59
1,33
0,23
8
1,44
0,49
1,69
0,19
5
6.
7
8.
9.
P-cymene
1-methyl-indan
Naphthalene
Phenantrene
Dehydroabietic acid
7,71
5,30
80,64
-
6,93
39,07
51,12
0,47
1,89
17,62
79,05
-
4,50
2,06
8,99
78,20
2,84
From Table4is seen that, HZSM-5 and themodified (Ni/HZSM-5, Cu-Ni/HZSM-5, NiMo/HZSM-5) could crack and brokethe–COOHgroup at abieticacid,neoabietic acid
anddehydroabietic acid and reduce the hydrogen bonds (dehydrogenationreaction) of
theresinacidstoformaromaticcompound.Buttheselectivity
thosecatalystsweredirectedintonaphthalene
and
of
phenanthrenecomponents,althoughCu-
Ni/HZSM-5 catalysthadthehighestselectivityto produce cumene (1,44%) at the pressure of 60
bar and temperature of 400º C. In ordertoobtainhighercompotition of cumene,
thereactionswerecarriedoutagainbyvariatingthepressureprocess(30,
45
and
60
bar).
Thecomponentsof productswithvariation of pressureare shown at table5 and figure 5.
Table5.GC-MS of products from cracking – dehydrogenation(T = 450º C.)
No.
1
2
3
4
Compound
Cumene
1-methyl-indan
Naphthalene
Phenantrene
%
60
bar
1,44
1,89
17,62
79,62
45
30
bar
bar
2,64 3,27
3,16 1,72
38,34 37,01
57,04 58,01
Table 5 showed the process of cracking by 30 bar of pressure better than the other.
The lower pressure is needed in this process because the reaction was exotherms, other
words, cracking-dehydrogenation need high temperature and low pressure.
9
Figure 5. Yield of cumene at 450º C in various pressure
CONCLUSION
The cracking-dehydrogenation using modified HZSM-5 could be used in the convertion
of rosin oil into cumene.The Cu-Ni/HZSM-5 catalyst had the highest selectivity to produce
cumene.The best operation condition of cracking-dehydrogenationprocess of cumene was
at30 bar and temperatur 450o C.The cumene concentration was 3,27%. Future activity on the
optimation of the processes to have better yield of cumene is necessary.
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11