SU27052A1 - Method for preparing phenolsulfonphalein (phenol-mouth) and orthocresolsulfonphthalein (cresol-mouth) - Google Patents

Description

In 1915-1916, in the American magazines O. Clard OM d. Lubs (Jour. Washingt Academ. Of Science 1915 (5 610, 1916 (6) 781) described a new group of sulfonphthalein indicators, which, due to their sharp and beautiful color transitions, quickly and with deserved success entered the practice of colorimetric determination of hydrogen ion concentration. Therefore, a convenient way to produce sulfonphthaleins in high yield is of considerable practical interest.

To date, the following methods have been described in the literature for the preparation of sulfonphthaleins: 1. Sohon. Amer. Journ. 1898. 263 (20). Phenolsulfonphalein and orthocresolsulfonphthalein, as well as their bromo-substituted derivatives, were obtained for the first time; indicated by the property of their solutions to change color depending on the reaction medium.

Method of preparation (abstract in Ch. Z 1898 II 1106). -Condensation of ortho-sulfobenzoic anhydride with phenol or orthocresol at 135-137 ° for l-8 hours, access to orthocresol and phenolsulfonphthalein about 50% of theory.

2. W. Clark a. N. Lubs. Journ. of

Washin. Acad. .of scien. 1915 r. 614 (5),

1916G. 481 (6).

The production method is the same as k in 1; some other sulfonphthaleins have been obtained; used to condense ortho-sulfobenzoyl chloride.

3.N. Lubs a S. Asgei. Journ. Asheg. Chem. Soc. 1916 (33) 2777.

Method p e beam N (abstract sCh.Z

1917 1,813):

a) Condensation of ortho-sulfobenzoic anhydride with phenol or orthocresol.

b) Condensation of ortho-sulfobenzoic chloride with phenol or orthocresol; the conditions described in the 2nd method are repeated. The yield on phenol and orthocresolsulfonphthalein is about 50%.

4.E. W h i t e a. S. And with g e e. Journ. Amer .. Chen. Soc. 1919 (41) 1193.

The method of preparation (abstract in Ch. Z. 1919 111 872) is basically no different from previous ones. Condensation of ortho-sulfobenzoic anhydride with phenol or orthocresol; heating b h. at 130-135 °; Exit about 50% of theory.

5.W. Orndorff A.- Sherword. Joi / r. Amer. Chem Soc. 1923 (45) 486.

The method of obtaining (abstract in Ch. Z. 1923 111 211) is basically not different from the previous ones, i.e. condensation of ortho-sulfobenzoic anhydride, or chloride, with phenol or orthocresol; heating -140 ° for 7 to 8 hours; yield about 50% of theory.

b. R. Tilas a. Provine. Jour. Yageg Cham. Soc. 1928 50) 2014.

Method of preparation (abstract in -Ch. Z 1928 II 886). Α-ortho-sulfobenzimide co-condensation. (saccharin) with phenol, in the presence of sulfuric acid as a water-removing agent, heated for 48 hours at 125 °, the yield of phenolsulfonphthalein is not indicated. It can be assumed that the reaction is not going smoothly and the yield is not high. (See original work).

The work of Orndorff - Sherwood (see 5) is most significant, since the authors

he

ketone form

WITH

SO, OH

At 135-140, the intermediate product is converted to sulfonphthalein (phenol or orthocresol).

.so with “Hj ons Se H4 o

2SbN4 Sat H4

ZOHONSOjOH

a pair of hydroxybenzoylbenzene - ortho-sulfonic acid - -phenolsulfonphthalein (phenolrot). Establishment of the structure of sulfonphthaleins, see original work 5.

As can be seen from the above works, until recently, the method of obtaining phenol- and ortho-cresolsulfonphthalein was largely unchanged, since the starting material is ortho-sulfobenzoic anhydride ortho-sulfobenzoic chloride with ortho-sulfobenzimide (saccharin), and the yield for products does not exceed 50% of theory.

Condensation of water separating agents

(, 5 "a" AICIs, etc.)

firmly established the mechanism of the condensation reaction of ortho-sulfobenzoic anhydride with phenol and orthocresol, namely: the reaction proceeds in two phases 1) first formed from one molecule: anhydride and one molecule of phenol (or orthocresol) intermediate compound, paraoxybenzoyl benzene - ortho-sulfonic acid:

SO) CaH450, + C “H50N

Sat. he

He h4 zoz he

which can exist in two tautomeric forms in the form of a lactone and in a ketone form

HE

x

Lactone form

burned

so

CeHiOH

does not increase the yield, but reduces the reaction time (see literature).

The preparation of the mentioned starting materials is associated with known experimental difficulties, besides / their synthesis takes place over several phases and lasts a relatively long time.

The proposed method is aimed at obtaining -phenol and orthocresolsulfonphthalein with higher yields than the methods described so far.

The formation of phenol and orthocresolsulfonphthalein by this method proceeds by heating the ortho-sulfobenzoic acid itself as an aqueous, composition

soon

Znz oh

Sbn

H5Oz and anhydrous, composition

Cun

Sat NC

Н50з

with phenol (or orthocresol), if the reaction temperature is maintained not lower than 156-158%, then the yield per phenolot reaches 50–60% of theory, and up to 70–85% of theory per cresolt.

The reaction proceeds in the absence of

water splitting agents during 2.5 - 3 hours.

(Z, a ,, .AI Cis, and others.) Are included. 2.5-3 hours

In view of the fact that water is continuously removed during the reaction, the amount of which is five times more than when condensed with ortho-sulfobenzoic anhydride when aqueous acid is consumed and two times more if it is anhydrous, it is necessary to take such an excess of phenol , against the theory required, that by the end of the reaction the resulting sulfonphthalein does not contain free phenol, (or orthocresol), if possible; If this reaction is observed, the reaction product will be in crystalline form, in the form most convenient for further operations.

In addition, an excess of phenol (or h of tocresol) serves as the reaction medium, the solvent from which, as it forms, the crystalline reaction product gradually separates.

The equation for the reaction of ortho-sulfobenzoic acid with phenol (or orthocresol):

Cun

, / - HQH40H

a) j || SOa OH ZN. O-I / HCeHiOH

M 202 + 54 25b 2M 94 + 94 188 ji crystallization Phenol M 354

rtosulfobenzoine c-taPhenolsulfonphalein

Cun

.OH

c) j 1 so, OH +

/НСВН.ОН

 2M 94 + 94 188

Anhydrous ortho-sulfobenzoic acid

(

HE

X

- about

f | 5О.ОН

(phenolrot).

 HE

 Have

- about so. It is to form the ortok CUNSH.HLH JlSOaOH.SHaO I / 1, / nsn Aqueous crystalline ortho-sulfobenz. c) .... likewise To explain the high outputs, the following assumption can be made. When phenol (or orthocresol) is heated with ortho-sulfobenzoic anhydride (or chloride), mono- or diphenolic (or ortho-cresolic) ortho-sulfobenzoic acid esters are always formed; this side reaction seems to lower to a large extent the yield to sulfonphthalein. When phenol (or orthocresol) is reacted with ortho-sulfobenzoic acid itself (aqueous or anhydrous), due to the formation of a large amount of water, the esterification conditions are less than 6; agrite; therefore, the main reaction will be the formation of sulfonphthaleins, i.e. output boost mc. Example 1. Phenol sul lfont alein (from crystalline, aqueous ortho-sulfobenzoic acid and phenol). To 256.0 molten and heated to 150 ° crystalline ortho-sulfobenzoic acid of the composition (COOH1) CcH, H3AO, 502 OH2), 500 g of phenol heated to 165-170 are added. The temperature of the mixture rapidly drops to 140-150 °. The mixture is heated to 158 ° -160 and maintained at this temperature during the entire reaction time. The mixture soars strongly, separating water and phenolic vapors; the color of the liquid quickly turns red, after 50-55 minutes, the release of small phenolrot crystals begins. At the time of the appearance of crystals, the release of vapors (water and phenolic) is significantly weakened. After the first hour of heating, it is necessary to start 2M 1 Ohr ezolsulfonfaleyia:. OH - GM 1 + 08 21b .OH okrezol Ortokresolsulfonphthalein (cresolrot). mixing as the mixture starts to thicken noticeably. After 2.5 - 3 hours. the reaction is completed, the vapor is almost not released, and the mixture thickens to n | 1 Cr-. steel porridge. To the somewhat cooled reaction mixture, 2-2.5 liters of water are poured, boiled for 20 minutes, cooled to the same temperature, the crystalline powder is filtered off with suction and washed several times with cold water. After drying, the weight of the reaction phenolrota reaches 200-225 g, i.e. 55 - 60% of theory. Further purification from by-products (about 3%) is carried out in the usual way. Example 2. Phenol sulphine phthalates n (from anhydrous crystal; 1ccc. Cstosulfobenzoic acid and phenol). 202 g of crystalline anhydrous ortho-sulfobenzoic acid of the composition / С00№) С,: Н, (AND ZOZON) 350 i phenol. Conditions as in example 1; taught crystallization in 35-40 minutes, reanzi two or two hours and 30 minutes. The yield of pure phenolot is about 180 g, i.e. 509-6. Example. 3. Orthocresolsulfonuthein Lein (From aqueous acid and orthocresol). 256 g of crystals aqueous ortho-sulfobenzoic acid and 550 g of orthocresol. Conditions as in example 1; reaction temperature 156 - 158, onset of crystallization after 40 - 45 minutes, reaction time 2.5 - 3 hours, the reaction product in the form of a very thick crystalline porridge, or in the form of an almost dry, crystalline powder. The yield of the pure product is up to 325 g. 85% of theory. Example 4. Orthocresolsulfonphalein (from anhydrous acid). 202 g of anhydrous ortho-sulfobenzoic acid and 350 g of orthocresol. Conditions as in example 3; the onset of crystallization in 30 - 35 minutes, the reaction time 2 - 2.5 hours; a pure product is obtained up to 270 i. 70% of theory.

The subject matter of the invention.

A method of producing phenolsulfonphalein (phenolrot) and cresolsulfonphthalein cresolrot), characterized in that an aqueous or anhydrous orthosupphobenzoic acid is condensed at elevated temperatures with fenrl or cresol theory.