To make clear the mechanism of chlorination of lignin by an aqueous solution, chlorination of lignin and model compounds has been investigated since some years ago.
In advance of the investigaton of the complex lignin-like models, guaiacol was investigated firstly, because it would be thought to show the fundamental principle of the chlorination reaction of the benzene nucleus.
Part 1.
A homogeneous aqueous solution of guaiacol (128 gr guaiacol/7l water) was treated with 7.5l of aqueous chlorine solution (molar ratio 1 : 1) for about 1/2 hr . at 0°C, a small portion of sodium solution was added to destroy the excess of remaining chlorine or hypochlorous acid if any, pH adjusted to nine with sodium hydroxide, sodium borohydride added in order to avoid the polymerization of quinoidal structure if any, acidified, the resinous products separated (I), and the whole was extracted continuously with chloroform (II) followed by ether (III).
I and II were distilled in vacuo into four fractions respectively, each fraction was examined gas chromatographically, and the fractions containing similar components were combined.
From the five fractions thus obtained the following compounds were separated and identified.
1) Guaiacol : as 3.5-dinitro-benzoate, m. p. 137°-139°C.
2) 5-Cbloroguaiacol : as 3.5-clinitro-benzoate, rn. p.170°-171.5°C.
3) 4.5-dichloroguaiacol : White needles, m. p. 71°-73°C.
The melting points of these three compounds are not depressed on admixture with the authentic samples.
4) Trichloroguaiacol : Pale yellow needles, m. p. 103°-106°C.
The position of chlorine atoms are not settled as yet.
5) 3-3′-Dimethoxy 4-4′-dihydroxydiphenyl : White prisms, melting at 166°-167°C. Diacetyl derivative, melting at 200.5°-202°C. Dimethyl derivative (biveratrol), melting at 132°-133°C.
Melting points of the diphenyl and its two derivatives agree well with the values reported in literatures.
The diphenyl has one phenolic hydroxyl group per methoxyl group, according to the so-called Δε-method of Aulin-Erdtman.
From III the following compounds were separated and identified.
1) Pyrocatechol : White prisms, melting at 103.5°-104.5°C.
2) 3-Chloropyrocatechol : The compound was isolated as mono carboxymethyl ether, melting at 122-123.5°C. undepressed on admixture with the authentic sample of 3-chlorocatechol monocarboxy methyl ether.
The position of the carboxymethyl group of the monoether is not determined. Diether was not prepared, as it was found to be difficult to etherify both hydroxyl groups of 3-chloropyrocatechol by an.usual method.
Part 2.
0.48, 1.09, 3.15 and 4.23 moles of chlorine were brought into reaction with one mol of guaiacol, just as in the case of part I. Excess chlorine was removed by allylalcohol, and the solution was extracted
with ether without being preceeded by any reduction with sodium borohydride.
Pyrocatechol and 3-chloropyrocatechol were identified in the extract by paper chromatography using benzene : acetic acid : water =1 : 1 : 2 as mobile phase, confirming the direct formation of pyrocatechol structure by the chlorination of guaicol.
Results so far obtained on the effects of aqueous chlorine water on the guaiacol nucleus are summarized as follows :
1) Methoxyl group is demethylated to give methanol in high yield.
2) Isolation of pyrocatechol suggests that demethylation can occur without introduction of any chlorine atoms into the nucleus.
3) One to three chlorine atoms are introduced without cleavage of methoxyl groups.
4) It seems therefore to be probable that chlorination of the nucleus and the demethylation of methoxyl group are independent reactions.
5) Guaiacol dimerizes by dehydrogenation.

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Corn starch was selectively oxidized by sodium meta periodate to afford dialdehyde starch of which degree of oxidation was 92.1%.
The reactions of the dialdehyde starch with urea in various conditions were studied.
It was found that 0.12 moles of urea were added to the dialdehyde starch even in pH 2.6 at 25-30°C within three hours, and that a maximum of 0.44 moles of urea was added at 55-60°C. The extent of reaction of urea was not more than one mole in other conditions of reaction.
The reaction products are high polymers carrying a number of both aldehyde and amide groups along, the molecular chain. They are hoped for many interesting applications in paper industry. The investigations are now continuing in our laboratory.

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Effects of fiber length on mechanical strength, chemical strength, chemical properties and hygroscopic characteristics were investigated. Mechanical strength especially was measured inthe normal condition (R.H. 65%) and dry condition. The dry condition was obtained by the folloNN ing ways ; the paper sample was dried at 105°C for 3hr, and was impregnated with water-free oil.
1) Tensile strength for fraction pulp decreases with increasing average fiber length, and in case of the same average fiber length, the tensile strength for whole pulp is higher than that for fraction pulp.
2) Folding endurance and tearing resistance for fraction pulp increase with increasing average fiber length. There is a straight-line relationship between the average fiber length and tearing resistance of paper.
3) Pentosan content of pulp decreases with increasing average fiber length, but DP of pulp increases.
4) Moisture regain, dimensional change, water of monolayer absorption and internal surface area of paper decrease with increasing average fiber length, but crystallinites of paper fiber increase.

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In previous study, the author confirmed that if the unbleached sulfite pulp was digested with some kind of alkaline solutions, the yields of them at a given level of alpha-cellulose content were not always the same.
In this paper it was tried to clear to which constituents' degradation and dissolution of the unbleached pulp during alkaline digestion these differences in yields are ascribed, using cotton linter and extracted hemi-cellulose (from unbleached sulfite pulp of hardwood).
1. When cotton linter is digested at high temperature with a caustic solution or mixed solution of sodium carbonate and sodium sulfite, its degradation is much severe with the former solution (Fig. 2 and. 3).
2. When extracted hemi-cellulose is digested at high temperature with the solutions above mentioned, dissolution is faster and undissolved residues are less with a caustic solution (Fig. 5).
3. The reasons why the yields of digested pulp with a caustic solution is lower than with other alkaline solutions seems to be due to much degradation of cellulose fiber (DP shown in previous paper and Fig. 8) and plenty of carbohydrates of short chain length dissoluted such as measured with 5 % caustic solution (Fig. 7).
4. Digested pulp with a caustic solution is lower in polymolecularity than with other alkaline solutions (Table. 4), but composition of carbohydrates constituents are almost the same at a given alphacellulose content (Fig. 11)

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