PARTⅤ SOLVOLYSISRECOVERY OF ORGANIC CHEMICALS AND
INORGANIC MATERIALS BY THE TREATMENT OFLASTIC-INORGANIC COMPOSITES IN
HIGH-TEMPERATURE WATER
Pei Yan*,1 Shigemitsu Itagaki,1 Ken-ichi Takahashi,2 Ken-etsu Katagiri,2Hideyuki Tagaya1
1Graduate School of Science and Engineering, Yamagata University, 4-3-16, Jonan,Yonezawa, Yamagata 992-8510, Japan.
E-mail: tagaya@yz.yamagata-u.ac.jp
2Tendokankyo Co. Ltd. 1280-1, Araya, Tendo, Yamagata 994-0054, Japan.

Abstract: It is not easy to recover organic and inorganic compounds from waste IC devices
because inorganic valuable materials of them were covered and protected by thermosetting
resin such as epoxy resin. Incineration treatment was believed as the possible recycling
process of inorganic valuable materials. However, organic compounds were no recovered. We
have already indicated that molding materials of thermosetting resin such as phenol resin andepoxy resin could be decomposed easily into their monomers in sub- and supercritical water.
In this study recovery of organic chemicals and inorganic materials was attained by thetreatment of various plastic – inorganic composites in high-temperature water. We haveconfirmed the effects of pretreatment and reaction conditions such as temperature, reaction
time and additives on the yields of products.
1. Introduction
It is well known plastic is an important material to modern times. Plastic is the generalcommon term for a wide range of synthetic or semisynthetic organic amorphous solidmatericals suitable for the manufacture of industrial products. However, along with plastic
manufacture's development, we are facing a lot of questions which are more and more severe,such as resources, environment and recycling.
In recent years, supercritical water has been received more and more attention as amedium for chemical reaction[1-3], because that supercritical water behaves similar toorganic solvents having high thermal stability.[4,5] We have already reported decomposition
reactions of plastics including thermosetting resin into their monomeric compounds insupercritical water.[6,7] The addition of basic compounds such as Na2CO3 was effective on- 245 -The 5th ISFR (October 11-14, 2009, Chengdu, China)
the decomposition reaction. Furthermore, chemical participation of water on the reaction wassuggested.
In this study, to obtain information on the decomposition reaction of plastics-inorganic
composites in high-temperature, various IC waste devices and then model compounds weretreated in high-temperature by using a 10 ml tubing bomb reactor.
2. Experimental
2.1 General
The organic products after decomposition were identified qualitatively by gas
chromatography-mass spectrometry (GC-MS, Shimadzu, QP-5000, Column CBJ-M30-025,
T=50oC, Tmax=270oC, Trated=10oC/min) and were analyzed quantitatively by gas
chromatography (GC-9A, Shimadzu, FID, Column SE-30(OV-1), T=130oC, Tmax=250oC, T
rated=10oC/min). Morphology of the samples was investigated using a scanning electron

microscope (JEOLJSM-6330F, SEM) equipped with EDS (JEOL, Super Mini-cup, EDS). The
images were analyzed with a computer (JEOL JED-2140) with EDS-ZAF correction software.
2.2 Materials
Various IC waste devices were provided by Tendokankyo Co.Ltd. Dry acetone,
Diphenyl (TCI) N,N-Diethylformamide (Wako) Diethylether, phenol, Na2CO3 (KANTO)
were used for the phenol resin decomposition reactions.
2.3 Decomposition reaction (Typical Procedure)
Decomposition reactions in high-temperature water or/and Na2CO3(3wt% or 10wt%)
mixture were carried out by 10 ml tubing bomb reactor. Typically, 0.1 g of IC waste device
was introduced in the tubing bomb reactor. The reaction was carried out at 430oC withassigning reaction time. After decomposition reaction, solid residuum was dried, analyzed bySEM, and the liquid product was extracted with organic solvents and identified by GC/MSand quantified by GC with a flame ionization detector (FID).
3. Results and discussion
The effect of various conditions on the decomposition reaction using IC sample 1 wasexamined, such as additive, temperature and reaction time (Fig. 1). The reactions withhigh-temperature water in the absence of additive for 1h, 3h, 5h, 7h, respectively, werecarried out (A). The result that as treatment time increases, the effect of decomposition
reaction has been changed for the better, nevertheless, the presence of unreacted plastic on
the surface of the metal was observed. Then Na2CO3 (3wt%) was added in thehigh-temperature water which applied to the reactions (B). The decomposition reaction
proceeded smoothly than reaction A, whereas which did not completely decompose. In order
to increase decomposition of IC waste device at high reaction temperature, the step-method- 246 -PARTⅤ SOLVOLYSIS
C with Na2CO3 (3wt%) was then investigated. This work was the best effective way todecompose organic and inorganic IC waste devices. In this treatment, the decomposition ofIC waste device, probably its reaction time, additive, and physical deterioration effects wasalso an important factor for the decomposition process.
Tab. 1 shows the GC/MS analysis of residual component obtained using the method B
and C. The yields of monomers in the recovery solution obtained with step-method C at
400oC (runs a′′-d′′) were identical to those for the reaction without step-method B (runs a′-d′).
It was confirmed that only decomposition reaction of IC waste device at the surface wasaccelerated by using step-method in Na2CO3 aqueous solution. In the case of d′′, the yield ofphenol reached 1.68%, 2-methylphenol reached 2.92%, and 2,4-dimethylphenol reached1.66%. It is considered that phenol and its derivatives can be reused as raw materials ofplastics such as phenol resin.
Tab. 1 shows the GC/MS analysis of residual component obtained using the method Band C. The yields of monomers in the recovery solution obtained with step-method C at
400oC (runs a′′-d′′) were identical to those for the reaction without step-method B (runs a′-d′).
It was confirmed that only decomposition reaction of IC waste device at the surface wasaccelerated by using step-method in Na2CO3 aqueous solution. In the case of d′′, the yield ofphenol reached 1.68%, 2-methylphenol reached 2.92%, and 2,4-dimethylphenol reached1.66%. It is considered that phenol and its derivatives can be reused as raw materials ofplastics such as phenol resin.
Tab. 1 The GC/MS analysis of residual component in the recovery solution
methodrun

Phenolyield (wt%)

2-methylphenol
yield (wt%)

2,4-dimethylphenol
yield (wt%)

B
B
B
B

a′b′
c′
d′

1.48
1.49
1.49
1.50

2.81
2.82
2.83
2.83

1.29
1.33
1.35
1.38

CCCC

a′′
b′′c′′d′′1.48
1.531.62
1.68

2.82
2.86
2.88
2.92

1.51
1.62
1.64
1.66

- 247 -The 5th ISFR (October 11-14, 2009, Chengdu, China)

Fig. 1 The image of the IC sample 1 after decomposition reaction (A) only 1.0ml
high-temperature water (a) reaction time: 1h, (b) 3h, (c) 5h (d) 7h; (B) a mixture of
3wt% NaCO3 and 1.0ml high-temperature water (a′) 1h, (b′) 3h (c′) 5h (d′) 7h (C) The
step reaction with natural cooling or forced cooling (a′′) heating 2h→natural cooling
1h→heating 2h (b′′) heating 2h→forced
Thermal decomposition of IC sample 2 was carried out at 430oC for 2h (Fig.2). In thiscase, the addition of Na2CO3 was shown to have a marked effect on the decomposition
reaction. The reaction with high-temperature water in the absence of additive for 2h resulted
in a poor yield of monomers, although body part of IC sample 2 was completely decomposed(b). In contrast, the decomposition reaction in the presence of additive was given a good yieldof monomers, and the organic resin of connecting part which accepted thermal reaction wasalso decomposed, but not completely (c). With the increase of the amount of additive, Na2CO3(10wt%) was shown have a significant effect and yield. Whether it was the body orconnecting part has been completely decomposed (d).

(a)

(b)

(c)

(d)oFig. 2 The image of the IC sample 2 after decomposition reaction at 430 C for 2h(a) IC sample 2 before decomposition reaction (b) in the 1ml high-temperature water(c) Na2CO3(3wt%) aqueous solution (d) Na2CO3(10wt%) aqueous solution- 248 -PARTⅤ SOLVOLYSIS
4. Conclusions
Effective decomposition reactions of various IC waste devices were carried out inhigh-temperature water or in Na2CO3 aqueous solution. Although due to different materials
for the decomposition reaction, the results did not achieve a unified. However, the results
suggested that water is excellent solvent for the decomposition reaction of IC waste devices toseparate organic and inorganic parts, and reaction time and additive are important factor for
effective decomposition reaction. These conditions can be applied to chemical recycling
process for manufacture's waste devices in high-temperature water.
References[1] T. Sako (Ed.), Chorinkai Ryutai, Agne shofusha, 2001.
[2] D. Bröll, C. Kaul, A. Krämer, P. Krammer, T. Richter, M. Jung, H.Vogel, P. Zehner,Angew. Chem. Ind. Ed. 1999, 38, 2998.
[3] P. E. Savage, Chem. Rev. 1999, 99, 603.
[4] N. Akiya, P. Savage, Chem. Rev. 2002, 102, 2725.
[5] R. Shaw, T. Bill, A. Clifford, C. Eckert, U. Franck, Chem Eng News.1991, 26, 26.
[6] Z. Y. Dai, B. Hatano, J. Kadokawa and H. Tagaya. Polym. Degrad. Stab. 2002, 76, 79.
[7] Z. Y. Dai, B. Hatano,H. Tagaya. Polym. Degrad. Stab. 2003, 80, 353.

- 249 -