transferred when attempting the separation, it can
prolong the purification process. In this experiment,
seedlac was hydrolysis after decolorized. The dyes
were obtained in the decolorized process ca be used
as natural dyes. Product hydrolysis was compared
with seedlac hydrolysis product without the
decolorized process.
2 MATERIALS AND METHOD
2.1 Materials
Seedlac was used in this experiment obtained from
Perhutani. The chemical materials used in this
experiment were methanol (Merck), potassium
hydroxide (Merck), ethyl acetate (Merck),
hydrochloric acid (Merck), n-hexane, and activated
charcoal.
2.2 Method
2.2.1 Seedlac Characterization
The characterization of seedlac includes moisture
contents, ash contents, and acid value. A Fourier
Transform Infrared (FTIR) spectra were collected for
seedlac to determine the functional group.
2.2.2 Extraction of Natural Dyes
(decolorized process)
Seedlac that have been crushed macerated using
water with a ratio of seedlac: water is 1:10.
Maceration is carried out for 3-4 hours at room
temperature while stirring (Yaqub et al., 2014),
2014). After maceration, filter the products, take the
filtrate as natural dyes and the pulp for hydrolysis.
2.2.3 Hydrolysis of Seedlac
There are 2 types of hydrolysed seedlac, one is
seedlac from the 2.3 process, namely decolorized
seedlac, and the second is pure seedlac. To a reflux
apparatus add 20 g of seedlac granules, 80 mL of
methanol and 11 g of potassium hydroxide dissolved
in 100 mL water, reflux for 15 minutes. Then the
methanol is distilled off completely and the solution
is then neutralized until pH 5 is reached. Then add 4
g of activated charcoal, filter while hot and let stand
for 3 days. Then the solution is filtered and the filtrate
is added to a beaker with boiling water. Add just
enough of ethyl acetate until all of the crude product
dissolves. 800 mg of activated charcoal and 2-4 g of
sodium sulphate is added and the solution is brought
to boil. The solution is filtered and few drops of n-
hexane are added, the solution is then allowed to
stand for 24 h and it is then filtered and dried.
2.2.4 Characterization of Seedlac Hydrolysis
A Fourier Transform Infrared (FTIR) spectra were
collected for seedlac hydrolysis to determine the
functional groups. Seedlac hydrolysis compounds
were identified by gas chromatography with a mass
spectrometer detector (GCMS) Agilent 6890 series
with capillary column HP-5MS, 30 m x 0.25 mm id x
0.25 µm film thickness. Helium gas was used as the
carrier gas at constant flow mode at 1.5 mL/min. The
sampel was injected with a volume of 2 µL in splitless
mode. The increasing of oven temperature was
programmed from 50-320°C with step of 10°C per
minute until reaching 320°C and hold 12 min.
3 RESULTS AND DISCUSSION
3.1 Characterization of Seedlac
Moisture content, ash content and acid value in this
experiment are presented in Table 1. The acid value
(AV) is a good indicator of the quality of seedlac
(Farag and Leopold, 2009). AV indicates the content
of acid available in the seedlac. AV was expressed as
the weight of KOH in mg needed to neutralize the
organic acids. Some studies reported seedlac has
various AV, ranging from 55 to 85 (Prasad, 2014).
During storage, polymerization induced by
esterification takes place, resulting in a decrease in
the AV (Farag and Leopold, 2009). AV in this study
is very low compared to AV in the literature already
mentioned.
The seedlac used in this experiment may have
been stored for a long time. Aldehydes are
susceptible to oxidation and the aldehyde groups in
seedlac are converted to carboxylic acid groups over
time (Shearer, 1989). The polymerization of
carboxylic acid can occur over time during storage.
There are also a large number of free hydroxyl groups
which are susceptible to further esterification during
storage. Therefore, AV has decreased.