Series of aluminum porphyrins such as alkyl(porphinato)aluminums or corresponding alcoholates, phenolates, carboxylates, chloride, thiolates and amides have been prepared, and exploited as novel, excellent catalysts, such as, for ( a ) ring-opening and addition polymerizations to synthesize polymers of uniform, controlled molecular weights, ( b ) chemical fixations and activations of carbon dioxide as a C¹ source for organic syntheses, and ( c ) highly stereoselective reductions of carbonyl compounds. The developments made here have disclosed the unusual reactivities of the central metal atom-axial ligand bonds of aluminum porphyrins arising from the nucleophilic reactivity of the axial group and Lewis acidic character of the metal centre. It is also noted that the photoexcitation of the porphyrin ring or the axial coordination of Lewis bases (amines and onium salts) to the back side of the aluminum porphyrin dramatically enhances the nucleophilic reactivity of the axial group. The developments also include the facile synthesis of a novel poly(oxyethylene)-linked porphyrin with amphiphilic character, which forms the face-to-face aggregates in aqueous media. The first successful optical resolution of chiral N-alkylporphyrin antipodes with enantiotopic porphyrin faces has been also achieved.

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Mixed oxide films of WO₃-MoO₃ with an electrochromic property have been cathodically deposited onto an electroconductive glass (NESA) from a colloidal solution of tungstic and molybdic acid mixture. The colloidal tungstic and molybdic acid solution was prepared as follows: at first a mixture of sodium tungstate and molybdate solution was filtered off through a cation-exchanger colunm. Then the isolated acid mixture was kept at a constant temperature for more than 70h to promote the polymerization of the acid mixture for aging.
As the aging of the solution proceeded, the specific conductivity of the solutio n decreased and attained a constant value.
The absorption spectrum of the deposited mixed oxide film showed a peak shift of the absorption maximum toward a shorter wavelength than that of the pure tungsten trioxide film, as was already reported by Shirmer et al. or by Faughnan et al. In the present experiment, the largest peak shift of this absorption spectrum was observed for the 7 : 3 mixture of WO₃ and MoO₃.
The molar ratio of WO₃, to MoO₃ in the deposited film was almost proportional to that of the electrolytic solution.

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IR spectra of nitrogen and methane adsorbed on NaZSM-5 zeolites with different compositions (SiO₂/Al₂O₃ mole ratio=23.3, 40, 4, and 49.8) and on HZSM-5 (SiO₂/Al₂O₃ mole ratio=23.3)were measured at 300 K under the pressures ranging from O.05 to 1.0 MPa.
The infrared forbidden bands of nitrogen and methane were induced by the adsorption on ZSM-5 zeolites, indicating that, even at room temperature, the adsorbates were perturbed by the electric fields of cationic adsorption sites located on the ZSM-5 zeolite surfaces. The magnitude of the electric fields (E) were estimated to be 1.5-1.8×10⁵ esu, which were slightly smaller than those obtained from an earlier study carried out at a low temperature (226 K). The E values were found to increase with an increase in the SiO₂/Al₂O₃ mole ratios of the ZSM-5 zeolite.
The analyses of the induced absorption band (peak position, peak width, and peak intensity)showed that the motional freedoms (libration, rotation and translation) of adrnolecules increased with the increase in temperature.

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In order to clarify the mechanism of ion transport across an amphoteric membrane with sulfonic acid and N-methylpyridinum groups as the exchange sites, membrane potential measurements were carried out. In this study, an investigation was made on a more complicated system in which two different electrolyte solutions were separated by an amphoteric membrane. The electrolyte concentration in phase( I ) was fixed at 10-2 moldm-3 and that in phase(11)was varied from 10^-3 to 10^-1 mol⋅dm^-3. The electrolytes adopted in these systems were KCl, NaCl, CaCl₂ and LaCl₃. From our membrane equations previously proposed and the m embrane potentials measured in the present system, the membrane permeability coefficient ratios of ions are evaluated.
The obtained ratios of the respective ions were compared and examined in Figs.4-6 and Tables 1 and 2.
As the results, the following conclusions were obtained: 1) The transport properties of the amphoteric membrane in this study are largely dependent on the cationic valence of electrolytes (Fig.1).2) In the case of different electrolyte solution systems, higher valentcations mainly control the ion transport properties of the membranes (Table 1).3) The permeability ratios evaluated from the membrane potentials approximately agreed with those from the electrodialysis in the previous study (Table 2).4) By taking account of the direction of ion transport within the membrane, it is concluded that the interaction among different cations was smaller than that among the same charged ions.

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Various alumina mixed oxides were prepared intending to obtain thermostable supports for catalyst. And the influences of preparation procedures, added components, their added amounts and raw materials on sintering of the mixed oxides were investigated by measuring their specific surface areas, X-ray diffractions, thermal gravimetric and differential thermal analyses.
The alumina mixed oxides prepared from alkoxides by a chemical mixing procedure showed higher specific surface areas than the corresponding ones prepared from -the same alkoxides by a coprecipitation procedure, when their calcination temperatures were less than 1200°C. But these mixed oxides prepared by the above procedures showed almost the same va lues in their specific surface areas one another, being calcined above 1200°C. When SrO, BaO, La₂O₃ and ZrO₂ were added into Al₂O₃ with 10 wt% proportion by the chemical mixing procedure, sintering of the mixed oxides was found to be depressed and the -Mixed oxides substantially showed higher specific surface areas than alumina alone. On the contrary, additions of MgO, CaO, and CeO₂ into Al₂O₃ with 10 wt% proportion accelerated sintering of the mixed oxides and lowered their specific surface areas. The alumina mixed oxides prepared from alkoxides generally showed higher specific surface areas and kept their amorphisms by higher temperatures than the corresponding ones prepared from nitrates. Among the additives used, BaO was the most effective for depressing the sintering of the alumina mixed oxides and the decrease of their specific surface areas. But, the composition of BaO/Al₂O₃ mixed oxides showing the highest specific surface areas was not constant at all calcination temperatures used but changed in the range of 10-20 wt% BaO according to the calcination temperatures. Both 10 wt% BaO/Al₂O₃ mixed oxides calcined for 100 h at 1000°C and 3 h at 1200°C were amorphous, and showed high surface areas of 139 m²/g and 96 m²/g, respectively.

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Adosrption amounts of several organic compounds at saturated pressure in gaseous phase were measured over fibrous activated carbon(ACF) which was prepared from the phenolic resin fabric and granular activated carbon(ACG) from coconuts shell.
The adsorption states of organic conpounds were studied on the basis of the comparison of condensed volume of adsorbates with micropore volume of ACFs and ACGs.
The effect of activation degree of ACFs on the diffusion of organic compounds was also studied.
Main results and informations obtained were as follows.
( 1 ) At saturated pressure, the adsorbates filled the micro pore volume fully whose pore radius was smaller than 10 nm. The densities of adsorbates in adsorption over ACFs were 0.8-1.0 times that of liquid state.
( 2 ) Chloroform, butane, isooctane and cyclopentene could be adsorbed into the micro pores where cyclohexane could not be adsorbed. Adsorption states of these compounds were regarded approximately as flat plane.
( 3 ) In the cases of ethyl- and propylcyclohexanes, capturing of alkyl chain in the micro pores facilitated the adsorption.
(4) Fick′s equatio n was applied well to molecular sieving adsorption of benzene; CHCl₃ and CCl₄ over ACFs.

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In the synthesis of gypsum from the aqueous solution with coexisting methanol, gypsum was precipitated as very fine crystals with decrease of solubility. These converted to gelatinous gypsum when the crystal growth rate was depressed by adsorbing alkyl radicals onto the surface of crystal nuclei. A study was made to investigate gelatinous conditions and filtrating conditions for crystallizing fibrous gypsum hemihydrate from the gel to make fibrous gypsum sheets. Characteristics of the fibrous sheet as product were determined by means of X-ray diffraction, thermal analysis (TG-DTA), scanning electron microscopic observations and dissolution test.
The unstable organogel was deposited by adding methanol to the saturated solution with gypsum dihydrate. Then the gelatinous phase crystallized as platy gypsum dihydrate or fibrous β-hemihydrate, while methanol was removed from the organogel by rapid filtrating with suction. However, the formation range of fibrous β-hemihydrate was affected by gelatinous conditions such as temperature, amount of methanol, aging time, and filtrating velocity of the gel. For an example, it was possible to make a sheet of intertwined β-hemihydrate fiber of about 200 (length 80 μm×∅ 0.4 μm) as aspect ratio under the following gelatinous conditions; temperature at 60°C, 67% methanol (50 cm³ saturated soln. +100 cm³ methanol), aging time for 5 min and filtrating velocity of 3 cm³/s.
Otherwise, the sheet of high crystalline II-anhydrous gypsum obtained by heating β-hemihydrate sheet at 800°C, kept the original form of the fibers without any breaking. It had a high flexibility, a low bulk density of 0.3 g/cm³ and a high resistability against water.

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Hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂; HAp) ultrafine powders sy nthesized by a wet method were treated under hydrothermal conditions. The HAp particles obtained at 200°C under 2MPa for 10 h were hexagonal prism-shaped fine single crystals, about 25 nm×90 nm in size, the median aspect ratio obtained from the transmission electron micrograph. was 3.2.
The quantitative chemical analysis, infrared (IR) spectra and X-ray diffraction (XRD), showed the presence of small amounts of CO₃^2- in the OH^- site. The HAp could be given by the formula: Ca₁₀(PO₄)₆(OH)_1.81±0.03(CO₃)_0.095±0.015.

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In the preparation of zirconium oxides through an alkoxide route, the parameters which affect the resultant oxide morphology were examined. These parameters included the type of alkyl groups in the alcoholic solvent, the aging temperature and time, the water/alkoxide ratio and the pH value of the hydrolysis water. Higher alkyl groups of the alcoholic solvent resulted in the large particles. Also, the particle size of the zirconia powders increased with the increasing water/alkoxide ratio as well as with the aging temperature. Longer aging resulted in the large agglomerate of the particles. A clear solution was obtainable after hydrolysis when the water/alkoxide ratio was less than 4 and the pH value of the hydrolysis water was 2. This clear solution condensed into transparent xerogels. Equia. xed particles were obtainable by the hydrolysis of 0.1 mol. alkoxide per litre of 1-butanol solution with ammoniated water of pI-I=10 in the case of the water/alkoxide ratio being 4. The morphology of the products was controllable by these parameters to obtain nearly monodispersed particles and monolithic gels.

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Complex formation of a water soluble porphyrin, 5, 10, 15, 20-tetrakis[4-(trimethylammonio)phenyl]porphyrin (ttmapp), with palladium(II) was studied. Although the reaction was very slow at room temperature, it was greatly accelerated to yield a Pd(II)-ttmapp complex in the presence of sodium L-ascorbate. When the sodium L-ascorbate concentration was over 0.05%, the reaction proceeded quantitatively in a pH range 3.9-5.9 within 2 min at room temperature. The complex was stable in a pH range 0.2-13. The soret peaks of ttmapp and the Pd(II) complex at pH 1.2 were 432 nm (ε=5.14×10⁵) and 409 nm (ε=3.06×10⁵), respectively. The recommended procedure for palladium(II) determination is as fol lows. To a sample solution containing palladium(II) 0-9.2 μg in a 50 cm³ measuring flask are added 1 cm³ of 2 mol⋅dm^-3 acetate buffer solution (pH =5), 1 cm³ of 9×10^-5 mol⋅dm^-3 ttmapp solution, and 1 cm³ of 10% sodium L-ascorbate solution. After standing for 5 min at room temperature, 5 cm³ of 5 mol⋅dm^-3 nitric acid is added to the solution followed by dilution to 50 cm³. The absorbance at 432 nm is measured against water. Tolerance limits are given for 28 metal ions and 6 anions. No metal ion interfered seriously with the determination. A linear calibration curve was obtained up to 184 ppb of palladium(II) and the sensitivity (Sandell index) was 0.205 ng Pd(II) cm^-2. The relative standard deviation was 0.56%(n=20). The present method exhibits a high selectivity and the highest sensitivity fot palladium(II). This method was applied to the determination of palladium and copper in dental alloy samples.

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A flame photometric detector (FPD) for micro liquid chromatography has been developed, where the eluent was introduced into FPD by an electrospray technique. This method is useful to detect such agricultural chemicals as contain sulfur and do not have UV absorbance. The quenching due to organic solvent was decreased by using such double flame burner similar to be used in gas chromatography.1-Propanol and 2-propanol used as eluent were nebulized and burned stably in hydrogen-air flame, but not for less polar liquids such as benzene and toluene by the electrospray method. On the other hand, 40% (v/v) 2-propanol/water did not burned stably in hydrogen-air flame, but burned stably in hydrogen-oxygen flame. The chromatograms of four alkyl phenylthiocarbamates were obtained with the ODS column (0.5 mm in i. d. and 110 mm in length, eluent: 40% (v/v) 2-propanol/water, flow rate: 8 μl/min) coupled with FPD detection. The optimum working conditions of FPD were as follows: flow rate of hydrogen for lower flame and upper flame were 72 ml/min and 109milmin, respectively, and flow rate of oxygen was 60 m//mm. The detection limit of hexan al thiosemicarbazone was 0.2 μg.

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A sensitive method for microdetermination of cyanide ion was developed by nonsuppressed ion chromatography(IC) with UV and conductometric(CD) detection. Cyanide ion- is converted to thiocyanate ion by the reaction with polysulfide ion and the latter is quantitatively determined by nonsuppressed IC using the mixed solution-1.3 mmol⋅dm^-3 in potassium gluconate-5.8 mmol⋅dm^-3 in boric acid-1.3 mmol⋅dm^-3 in sodium tetraborate -12% in acetonitrile 3% in 1-butano1-0.5% in glycerol (pH 8.5)-: as an eluent. Sample solution for ion chromatography was prepared by adding polysulfide four times more than equivalents to cyanide ion, and digesting for 20 min at 90°C in a water bath. The calibration curve for cyanide ion with UV detection (220 rim, 0.04 aufs) was linear in the concentration range of 0.05-2.5 ppm, and also linear with CD detection in the range of 0.25-2.5 ppm. In the case of UVdetection, the relative error of less than 2.2% and relative standard deviation(%) of less than 4.7%were obtained in the concentration range of 0.05-2.5 ppm cyanide. Detection limits of cyanide ion with UV and CD detection were 0.01 ppm and 0.1 ppm, respectively. Five-fold molar excess of common anions such as chloride, bromide, iodide, nitrate, sulfate and thiosulfate, and equimolar amounts of metal cations such as silver, mercury(II), lead(II), zinc, aluminium and iron(III) did not interfere. Presence of iron(II) and copper(II) interfered the determination.

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Gas chromatography with electron-capture detection (ECD-GC) provides a simple and rapid method for the determination of tributyltin and triphenyltin compounds in seawater. These compounds were converted into the corresponding chlorides with hydrochloric acid and hydrogenated with sodium tetrahydroborate. The organotin hydrides, tributyltin hydride (TBTH), and triphenyltin hydride (TPTH) were extracted with hexane and analyzed by ECD-GC. The gas chromatographic analysis was carried out a glass column packed with 10% Silicone OV-1 on Chromosorb W AW-DMCS (80-100 mesh). The detection limits were 0.5 ng for TBTH and 0.5 ng for TPTH. The recoveries of the overall performance of this method were 96-100% for tributyltin chloride (1 μg/ml) and 95-98% for triphenyltin chloride (1 μg/ml).

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The structure of polyesters which were prepared from 5-norbornene-2, 3-dicarboxylic anhydride as an acidic component and ethylene glycol or propylene glycol as an alcoholic cornponent has been analyzed by means of proton NMR spectroscopy. Extensive geometrical isomerization of carboxyl groups from cis-form to trans-form was observed in the early stage of polyesterification reaction. Mechanistic investigation suggested that the retro-DielsAlder reaction is responsible for the formation of trans-isomer.

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The transport and the selective separation of Mg²⁺ and Cu₂₊ through an amidoxime groupcontaining membrane, which was synthesized by the radiation-induced grafting of acr ylonitrile onto a polyethylene membrane followed by amidoximation of cyano groups with hydroxylamine, were investigated.
These metal ions in neutral solutions in the source phase transport through the membrane into the receiving phase which is composed of various concentrations of sulfuric acid or acetic acid-sodium acetate solutions.
The rate of transport of Cu²⁺ and Me ions increased with increasing the initial H⁺ concentration in the receiving phase. Cu²⁺ and Mg²⁺ ions were transported with H⁺ trans fer as a driving force. Transport efficiency of Cu²⁺ through the membrane was higher th an that of Mg²⁺. The ratio of the concentration (Cu²⁺/Mg²⁺) in the receiving phase increased and thereafter decreased gradually with the time to reach finally almost the constant value of about 4.5.
The transport selectivity is caused by the difference in the adsorption equilibrium resulting from the complex formation constant of each metal ion with amidoxime group.
It was found that the transport selectivity of metal ion is greatly influe n ced by pH when the ion permselectivity process occurred by using amidoxime group as a carrier.

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A chelating resin containing amidoxime groups for the recovery of uranium from seawater was synthesized by radiation-induced graft polymerization. Nonporous high-density polyethylene film, 50 μm thick, was used as a base polymer for grafting. The amidoxime resin in a membrane form, whose degree of grafting and thickness were 48.2% and 72 μm, was synthesized. Its adsorption capacity of copper and that of hydrochloric acid were 4.4 mol/kg and 2.1 mol/kg of base polymer, respectively. Either the pretreatment or recycle procedure of adsorption and desorption was performed on the amidoxime membrane. The effect of the treatment with hydrochloric acid, potassium hydroxide and potassium chloride solutions on the adsorbent dimensions, water content and adsorptive properties for copper was investigated. The treatment with potassium hydroxide solution was most effective for the increase in the swelling and in the water content of the membrane. The amidoxime membrane without pretreatment adsorbed little amount of copper. Once the amidoxime membrane was treated with potassium hydroxide solution, it adsorbed a sufficient amount of copper, and the adsorptive properties of the membrane was not changed by successive recycle procedures.

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An electric conduction mechanism and an effect of atmospheres in annealing processes on electric conductivity of Mn-Fe-Co-Ni oxide (Mn: Fe: Co: Ni=5.7: 4.0: 1.5: 1.0 in molar ratio) used for a thermistor material were investigated. The samples were prepared by firing a mixture of oxides, obtained from aqueous solutions of Mn, Fe, Co, and Ni nitrates, at 1400°C for 1 h and cooling in an electric furnace to room temperature after holding at 1000°C for 1 h during cooling.
The samples were annealed at 310°C and 370°C in atmospheres of oxygen, air, and argon in the apparatus as shown in Fig.1. The samples annealed at 370°C under above three atmospheres had the same crystal phases as that of the as-fired sample, that is, the cubic spinel phase. Annealing at 310°C in oxygen and air, on the contrary, yielded an additional tetragonal spinel phase; the phase transition from the cubic to the tetragonal phase occurred in an oxidizing atmosphere. During annealing at 310°C and 370°C in different atmospheres the electric conductivities (σ) and Seebeck potentials (Qs) were measured. While no change in σ a and Qs by annealing in argon was observed at 310°C and 370°C, σ increased due to the increase in the concentration of positive charge carriers and the decrease of σ was followed by annealing in oxygen and air, as shown in Figs.6 and 7. The position of the acceptor level (EA) and the activation energy of the movility (Eμ), as determined from the slopes of the in σT and Qs vs. T^-1 plots in Fig.5, were 27.1 and 28.3 kJ⋅mol^-1, respectively. With the aid of these data the jump frequency ν0 was found to be =5.4×10¹²s^-1, which is in the frequency range expected for optical phonons. These data can be explained satisfactorily in terms of a smallpolaron hopping model.

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A simple analytical method is proposed for obtaining thermal desorption curves and desorption efficiencies of binary mixtures of organic solvents from an activated carbon. Basic equations were obtained from mass balances in desorption column and adsorption isotherms assuming mass transfer rate to be infinite, and distribution of solvents in the column to be homogeneous in both gas and solid phases. Adsorption isotherm for pure solvent, which. has approximated by several straight lines, was extended to binary system. Thermal desorption experiments were carried out in the stream of nitrogen at 200°C. Although estimated values of initial adsorption rates tended to be higher than experimental values especially when initial adsorbed amounts were small, estimated desorption curves and desorption efficiencies agreed fairly well with experimental Ones.

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Key factors, which determine the properties of air electrode of high-temperature solid oxide fuel cells, were studied for the La_0.6Ca_0.4MO₃(M=Mn, Co)/stabilized zirconia (YSZ)electrode system. The microstructure of the electrode was observed by SEM (Figs.1-3). Measurements were made on the complex impedance (Fig.4), and steady-state cathodic p olarization (Fig.9) of the electrodes. The results were analysed in relation to the ele ctrode thickness (Figs.5-7, 10, 11) and the following conclusions were obtained. (1) The La_0.6Ca_0.4Co₃/YSZ system prepared at 1100°C formed a CaZrO₃ layer at the interface. The l ayer works as an electrode and, consequently, the properties of this electrode is determined by the properties of the CaZrO₃/YSZ interface. (2) The cathodic reaction at the La_0.6Ca_0.4Mn₃/YSZ interface proceeds by the following 3 stages, a) the adsorption of oxygen on the surface of La_0.6Mn_0.4Co₃, b) surface diffusion of adsorbed oxygen, and c) the charge-transfer reaction at the three phase boundary of gas, La_0.6Ca_0.4Mn₃ and YSZ. Since the reaction rate of adsorption of oxygen on the La_0.6Mn_0.4Co₃ is slow, large surface area of the por ous oxide electrode is required to obtain high current density.

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A highly sensitive method for spectrophotometric determination of lead(II) by use of a water-soluble porphyrin was developed.5, 10, 15, 20-Tetrakis[4-(trimethylammonio)phenyl]porphyrin (ttmapp) formed a lead(II) complex by heating for 5 min in an alkaline solution.. A high and constant absorbance of the complex was obtained in a pH range 9.1-.11.8. The soret band maximum of the complex (ε=3×10⁵) lies at 463 nm, separated substantially from that of free ttmapp (411nm). The tolerance limits of 22 metal ions are given. Lead(II) was separated from many metal ions by extraction with dithizone-carbon tetrachloride solution from alkaline solution followed by back extraction with 1 mol⋅dm^-3 nitric acid. The recommended procedure is as follows. Take 20-40 ml of a sample solution containing 0-20 μg of lead (II) into a 100 ml beaker and adjust the pH to 9.5 with a borate buffer. Heat the solution to 90°C and add 1 ml of a 4×10^-4 mol⋅dm^-3 ttmapp solution, then allow it to stand for 5 min at 90°C. After cooling to room temperature dilute the solution to 50 ml. Measure the absorvance at 463 nm against water. A straight calibration line was obtained up to at least 400 ppb lead, and the sensitivity (Sandell index) was 0.835 ngPb cm^-2. The relative standard deviation (n =10) was 1.7% for the spectrophotometry and 4.3% for the extractionspectrophotometry. This method was applied to the determination of lead in sewage water.

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A chelating resin was prepared by the reaction of a diphenyl phosphonate-formaldehyde resin with trietylenetetramine for 4 h about 100°C. The adsorption capacity of the resin, for divalent metal ions was 1.8 Cu²⁺ mmol/g-R (dry resin) and for trivalent metal ions 0.80 Cr³⁺ mmol/g-R. Elution curves for Ca²⁺, Mg²⁺, Cu²⁺, Cd²⁺, Zn²⁺, Co²⁺, Ni²⁺ and Pb²⁺ were recorded by using 0.02 mol/l citric acid and 0.0 5 mol/l HCl. The separation, of metal ions. from each other and the recovery of Ca²⁺ and Mg²⁺ from large amounts of other, divalent metal ions are facilitated. The resin also showed goosl adsorption of. Cr(III) from buffer solutions of pH 5.0-7.0 and of Cr₂O₇^2- from buffer solutions of pH 2.0-7.0.

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Formation of macromolecular complexes (MCs) of potassium metaphosphate (MPK) with [2-(diethylamino)ethyl]dextran hydrochloride (EA) or glycol chitosan (GC) has been studied. Phase diagrams in three-component system NaBr/acetone/H₂0 were achieved for M Cs prepared from the MPK-EA system at pH 1.0 and MPK-GC system at pH 1.0 to pH 5.0, but were not achieved in the other reaction systems.
The MCs prepared from the, MPK-EA and MPK-GC systems consisted of phosphate and/or metaphosphate with EA and GC, respectively.

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The fatty acids in hexane extracts of the milt of Alaska pollack (Theragla chalcogramma)were palmitic acid (23%), oleic acid (24%), eicosapentaenoic acid (EPA) (20%) and docosahexaenoic acid (DHA) (24%). However, in the case of supercritical carbon dioxide (SC-CO₂)extracts, the contents of these components were 11%, 20%, 32% and 25%, respectively, This is in sharp contrast to the reported results from extraction of fatty acids with SC-CO₂. As a reson for the difficulty in extracting palmitic acid with SC-CO₂, it was inferred that the palmitic acid in the milt of Alaska pollack exists as phospholipids in view of the results obtained by reextraction of a hexane extract with SC-CO₂. Therefore, the milt seems to be a material suitable for extracting EPA and DHA in high contents with SC-CO₂.

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