THE EFFECTS OF SOLVENTS ON THE CHEMICAL DECOMPOSITION OF
FOAMED PHENOL RESIN IN HIGH ―TEMPERATURE FLUIDS
T. Sugeno, H. Tagaya
Yamagata University, Graduate School of Science and Engineering
e-mail: ttm44014@st.yamagata-u.ac.jp

Abstract
In this study waste plastics such as phenol resin foam powder were decomposed into their monomer and oligomer
compounds in sub- and supercritical fluids. Solvents play important roles as stable physical medium at high temperature andreactive chemical reagents to accelerate decomposition reaction of the thermosetting resin. In the decomposition reaction at
relatively high temperature, methylene bonds of plastics were cleaved selectively via the ionic reaction by solvents. The
solvent participating mechanism of decomposition was confirmed to make clear the decomposition products of phenol resin
foam. The methylated reaction also occurred in the reaction in methanol, and cresol and trimethylphenol were found as main
products. Almost all foamed phenol resin was solubilized in the reaction in m-cresol and 1-heptanol suggesting new
solubilization mechanism.
Keywords: High Temperature Water, High Temperature Methanol, Phenol Resin, Thermosetting Resin,
Chemical Recycling

1. Introduction
The chemical recycling of waste plastics has been
gaining greater attention in recent years as a means ofobtaining valuable products from wastes. Thermal
cracking of thermosetting resin is a well-known techniqueand fluidized-bed pyrolysis technology has been underdevelopment. It is well known that water under
supercritical conditions is much less polar and canhomogenize substantial amounts of non-polar organiccompounds. Furthermore, it is pointed out that thesupercritical water is emerging as a medium, which could
provide the optimum conditions for a variety of chemical
reactions, among them the destruction of hazardous
waste. We have already confirmed that waste plastics
such as phenol resin decompose into their monomericcompounds in sub- and supercritical water (Fig.1) [1], [2].

phenol resin effectively. After the reaction, products
were extracted by ether and analyzed by GC and GC/MS(Fig.2). In the thermal analysis the temperature
increasing rate was 10ºC/min.

10 mL tubing bomb autoclaveor
2 L batch-type autoclave
Heating
Filtration

LiquidproductResidue

Ether extraction
High temperaturewater

Ether-soluble partFig.1. Decomposition reaction of foamed phenol resin.

Water-soluble part

GC,GC-MS

Fig.2. Experiment method.

2. Materials and Methods
Foamed phenol resin was reacted after pulverizing. A 10mL tubing bomb autoclave and 2 L batch-type autoclave
were used as the reactor. The typical reaction wascarried out for 0.1 g of foamed phenol resin in 1.0 mL
water with Na2CO3 or methanol. m-Cresol, toluene and1-heptanol which were the new solvents were used witha 10 mL tubing bomb autoclave to decompose foamed

3. Results and Discussion
3.1. Decomposition reaction in high temperature water
Foamed phenol resin was decomposed into theirmonomers by the reactions at 350ºC under an Ar
atmosphere in high temperature water with Na2CO3 for
2 h. According to GC/MS analysis, phenol and cresol

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013

Intensity [ arb.units ]

(a)

(b)

5101520
Time [min]25

Yield [wt%]704603(a)系列1502(b)系列2401(c)系列3300(d)系列4(e)
系列5(f)
系列6100phenolo-cresolp-cresol

2,4dimethylphenol

m-Cresol and toluene which have similar structure of
foamed phenol resin were used as the new solvent.
Foamed phenol resin hardly was decomposed in toluene
at 350ºC , while foamed phenol resin was decomposed
successfully and solubilized in m-cresol at 350ºC (Fig.5).
Therefore hydroxyl group play an important role for thedecomposition reaction. The total yields of the monomers
which were phenol, o-cresol, p-cresol and 2,4dimethylphenol were about 30% on decomposition
reaction in m-cresol at 350ºC. It was about 10 times of
the total yields of the monomers by decomposition
reaction in water with Na2CO3 at 350ºC.
1-Heptanol is a straight-chain compound and was used
to compare with the reaction of m-cresol. Not only
decomposition reaction in m-cresol, but also it in 1heptanol was able to solubilize foamed phenol resin.
7025602050

1540(a)
系
列1(b)
系
列2(c)
系
列3(d)
系
列410530
020Fig.3. GC/MS chromatogram of the products in thereaction of foamed phenol resin by using 2 L batch-type
autoclave (a) in water 400 mL with Na2CO3 at 350ºC for
1 h and (b) in methanol 400 mL at 280ºC for 1 h.

20

3.3. Examination of the new solvents

Yield [wt%]were found as main components in the liquid phase(Fig.3). The decomposition was accelerated by thequantity of Na2CO3 addition increasing. In addition, theyield of their monomers was higher at longer reaction
time and higher temperature (Fig.4). Residue wasproduced about 40% in the severe conditions. However,carbonization reaction occurred at the high reaction
temperature.

Residue

Fig.4. Decomposition reaction of foamed phenol resin inwater 1.0 mL with Na2CO3 for 2 h by using 10 mL tubing
bomb autoclave (a) at 280ºC, (b) at 300ºC, (c) at 320ºC,(d) at 350ºC, (e) at 400ºC, (f) at 430ºC.

100phenolo-cresolp-cresol

2,4dimethylphenol

Residue

Fig.5. Decomposition reaction of foamed phenol resin at350ºC for 2 h by using 10 mL tubing bomb autoclave (a)in water 1.0 mL with Na2CO3, (b) in methanol 1.0 mL, (c)in toluene 1.0 mL, (d) in m-cresol 1.0 mL.

4. Conclusions
Decomposition reaction of phenol resin foam could becarried out using methanol at around 300ºC. Indicatingthat the decomposition reaction proceeded at lower
temperature when methanol was used as the solvent.
However, solid residue was produced either solvent
above 35%. Meanwhile foamed phenol resin wasdecomposed successfully in m-cresol and 1-heptanol.

3.2. Decomposition reaction in high temperature
methanol

References

Foamed phenol resin was decomposed by reactions at280ºC in high temperature methanol without the additionof additive. However the decomposition ability of hightemperature methanol was lower than that of hightemperature water with Na2CO3 at 350ºC. Foamed
phenol resin decomposed mainly into 2,4,6trimethylphenol and xylene in high temperature methanol
as shown in Fig.3. It is considered that xylene wasproduced from the plasticizer.

[2] T. Sugeno and H. Tagaya. Treatment of phenol resin
foam powder and prepolymer in high-temperature fluids.
PACIFICHEM 2010, Honolulu, (2011); Abstract 587.

[1] T. Sugeno and H. Tagaya. Recycling of Polymeric
Waste Materials. FSRJ Symposium proceedings 13th,Chiba, (2010) 39–40.

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013