BE562099A

BE562099A -

Info

Publication number: BE562099A
Authority: BE
Priority date: 1956-11-02
Also published as: FR1193683A; DE1068019B

Description

       

  RESINES D'ECHANGE D'ANIONS DESTINEES A LA DECOLORATION

DU SUCRE.

  




  ANION EXCHANGE RESINS FOR DECOLORATION

SUGAR.

Claims

The sentence following the formula given in paragraph 3 [deg.]) Of the summary should be corrected so that it reads as follows: <EMI ID = 1.1>

necessary, so that the formula given in said paragraph of the summary encompasses the modes of execution according to the examples * According to several examples and according to the

<EMI ID = 2.1> The present invention. relates to anion exchange resins and their preparation and applications. It relates to insoluble nitrogenous resins

in aqueous solutions of acids, bases and salts and particularly suitable for application to the removal of colored bodies from sugar solutions.

does not consist of the reaction product of a tertiai amine � re and an insoluble and cross-linked copolymer of a vinyl aromatic hydrocarbon and an aromatic hydrocarbon

ney are insoluble aromatic and cross-linked vinyl copolymers containing substituent groups of general formula:

As acetals and cotais behave in the same way in the present invention and no distinction is usually made between them in the literature, the term acetal will be used hereinafter, it being understood that it relates to to both compounds. Essentially the term acetal denotes here a dialkoxyalkane in which the

ble, extremely basic, like the previous product, the resins according to the invention can be used in the treatment of liquids and acid gases to remove their acidity. However, in a very interesting industrial application, the resins according to the invention far exceed in their behavior other previously known ion exchange resins, namely in the bleaching of sugar. Thus the invention provides an exchange resin

tions sweetened with the aid of this resin, exhibiting exceptional industrial advantages over comparable materials and methods known hitherto. This is what will emerge from the following description of resins, their method of preparation and their application to the decoloration of

In the preferred method of manufacturing these improved resins, a well-defined series of operations is followed. First, a copolymer of insoluble hydrocarbons is prepared.

in the form of small particles is then reacted.

Alkylating agents can be suitably chosen from a mixture of aldehyde and a haloacid (for example parafor-

-ethane, -propane, -butane, pentane, -heltane, -heptane, -octane or -nonane. The copolymer thus obtained is then reacted with a tertiary amine, which gives a salt <EMI ID = 13.1>

final washing using an alkali metal alum hydroxide converts the quaternary ammonium salt to a quaternary ammonium hydroxide.

to prepare the resins according to the invention, the process can be subdivided into three main operations or stages in a manner comparable to that indicated in the example

preparing the hydrocarbon copolymer by polymerizing a monovinyl hydrocarbon with a divynilic hydrocarbon. Thus, an aromatic hydrocarbon is copolymerized

<EMI ID = 15.1> material containing two vinyl substituents. Types of hydrocarbons in the first category are styrene,

anthracene, and their counterparts. Divinyl-benzene is the particularly recommended divinyl hydrocarbon, but other divinyl-hydrocarbons are suitable, such as divinyl-toluenes, divinyl-naphthalenes, divinyl-benzenes.

To prepare the copolymers, the monovinyl hydrocarbon is used in a predominant molar amount. So

in months of the vinyl hydrocarbon mixture. In cases where. it is preferred that the final resinous product is porous,

which is generally the case when applied to the discoloration of sugar, it is preferable that the amount of hydro-

the. Even larger amounts of divinyl hydrocarbon can be used when porosity is not as important, but it must be in an amount significantly less than the amount of monovinyl hydrocarbon involved Copolymers of a retive divinyl hydrocarbon both and of a mixture of two or more monovinyl hydrocarbons fall within the scope of the invention. As examples of such combinations, there may be mentioned styrene, ethylvinyl-benzene and divinyl-benzene; styrene, vinylnaphthalene and divinyl benzene; m-methyl-styrene, styrene and divinyl-benzene and styrene and divinylbenzene.

Insoluble copolymers of mono- and divinyl aromatic hydrocarbons can be prepared by a variety of well-known methods. So the monomers can. be mixed and then polymerized in bulk or be emulsified or otherwise suspended in a thick polymerized liquid medium. Emulsion and suspension polymerizations in which the monomers are first suspended in a non-solvent for the monomers, such as water or brine, then heated, stirred, and copolymerized, are much preferable since they are give copolymers

It is thus possible to prepare particles with a size of between 4 mm and 44 microns. Extremely fine particles

interesting in certain ion adsorption techniques. In addition, very fine or porous particles can be

in accordance with the invention and ultimately aminated faster and more extensively than larger and (or.) denser particles. a variant of the

te immiscible with the suspending liquid, then to remove the occluded or trapped solvent by leaching, se-

process results in resin particles which are more porous due to the removal of the solvent and which, due to their

adorn large masses or large blocks of polymer which are then subdivided before subjecting them to haloaloylating and acetalizing treatments.

The polymerization of vinyl compounds is accelerated by the well known initiators providing radi-

organic peroxides the types of which are ozonides, peroxides such as acetyl peroxide, lau- peroxide

<EMI ID = 27.1> tertiary, benzoyl peroxide, tertiary butyl perbenzoate, tertiary dibutyl diperphthalate, peroxy-

About 2% of the weight of the monomeric materials to be polymerized.

The second stage or part B of the preparation of the products according to the invention comprises the treatment of the insoluble polyvinyl hydrocarbon, infusible and crossified with the

tion comprises the treatment of the polymer by means of acetal at the same time that several bromoalkyl groups are introduced therein, or. preferably chloroalkyl. Through. these groups, we. means those which have the general formula given above: <EMI ID = 30.1>

branched.

The haloalkylation stage can be carried out in various ways. For example, the polymer can be reacted with a mixture of an aldehyde and hydrochloric acid, or

<EMI ID = 31.1> you amination using a tertiary amine of the copolymer which has been treated with the alkyl halide and acetal, This reaction is preferably carried out by adding the amine to the polymer resulting from the treatments described in part B above, while said polymer is in suspension and stirred in a liquid constituting a solvent for the amine. The mixture can be allowed to react at room temperature or preferably at somewhat higher temperatures, and then free from liquid the resin containing the quaternary ammonium salt groups.

The tertiary amine is used in the form of the base li-

The amine compounds can be alkyl, aryl, cycloalkyl, and aralkyl groups. Suitable tertiary amine types are trimethylamine, triethyl- and

diphenyl-ethyl-amine, benzyl-dimethylamine, benzylphenyl-methylamine; dimethyl-amino-ethanol and other bydro-

As has been said, the products according to the invention are insoluble and infusible quaternary ammonium compounds. As obtained, they are quaternary ammonium salts, but these salts can be easily converted to quaternary ammonium bydroxides by washing with an alkali metal hydroxide.

The following examples illustrate the preferred processes for preparing the products according to the invention. Example- 1 -

In a 1 liter three-nozzle flask fitted with a thermometer, a mechanical stirrer and a. conden-

the same time. The reaction mixture is then cooled to room temperature and the solid spheroids are separated from the copolymer from the liquid by decantation and filtration, they are dried in air and then in an oven for about eight hours.

zene.

Part b

In a five-liter three-necked flask fitted with a thermometer, a mechanical stirrer and a reflux condenser, the following materials are placed in accordance with

Methylal tee used is based on the weight of the copolymer beads. As explained below, the weight of

then and the contents of the flask are stirred for ten minutes. The beads from part A are then introduced, and the whole is stirred for half an hour at a temperature

the aluminum chloride is added in portions of about one-sixth of the total amount at intervals of twenty minutes. The reaction mixture is cooled by any means

and, this temperature is maintained for about six hours. Ice water is added until the flask is almost full, then the contents are stirred and allowed to settle in two phases or layers. The aqueous layer and the ethylene dichloride layer are siphoned off, the flask is filled with ordinary water, stirred again for half an hour and then allowed to stand and the liquor is siphoned off, which is then almost completely made up. of water. Fill the flask with plain water and add approximately

30 g of sodium bicarbonate. The contents are stirred for one hour, allowed to settle and the water is again separated by siphoning. Wash again twice with ordinary water, stir for about ten minutes, leave to settle and set. decant the water.

Fence -

The wet beads obtained in part B above are used as they are, in the operation which follows. 1790 g of wet beads and 2440 g of plain water are introduced into a five-liter three-necked flask muai of a stirrer, reflux condenser, thermometer and gas inlet tube. . The mixture is stirred at about 30 [deg.] C. then 170 g of gaseous trimethylamine are introduced through the tube

cooling water sent intermittently. The mixture is maintained at this temperature for about two hours, then stirred at reflux and the distillate removed through the condenser to remove ethylene dichloride and excess trimethylamine. When we have reached the temperature

balloon to maintain the initial liquid level. The removal of the distillate is continued until all that remains is water, ie there is no more organic matter. The liquor (water) is then siphoned off and the beads are washed with water until the wash water has a neutral pH. The excess water is siphoned off under suction and the wet beads remain, which constitute the product

Example 2 -

Part B 10% methylal by weight of the copolymer beads is used.

Example 3 -

The procedure is as in Example 1 except that in par-

copolymer.

Example 4 -

The procedure is as in Example 1 except that in

copolymer.

Example 5 -

The procedure is as in Example 1 except that in

copolymer.

Example 6 -

The procedure is as in Example 1 except that in part B 37% of methylal is used by weight of the copolymer beads.

The procedure is as in Example 1 except that in part B 40% by weight of methylal by weight of the copolymer beads is used.

Example 8 -

The procedure is as in Example 1 except that in

methylal. <EMI ID = 52.1>

The procedure is as in Example 1 except that in

methylal.

Example 10 -

The procedure is as in Example 1 except that in par-

Illustrations of the advantages of the resin according to the invention are given below. As the most dramatic improvement over the old ion exchange resins, we can cite the considerably superior results obtained in the decoloration of sugar, examples of this function.

Describe a recently developed test method for the bleaching capacity of sugar. It essentially consists of the following operations. We dissolve a given weight

recently prepared before each test because bacterial growth in the solution would render the test worthless. Portions of 35 ml of the sugar solution thus prepared are placed in four 50 ml graduated cylinders and a sample of the resin to be tested is placed in each of the test tubes in an amount such that the volume is brought to 37 ml for the first, 40 for the second,

45 for the third and 50 for the fourth. Each of the test tubes is emptied into a corresponding flask with a rinsing portion of 15 ml of the sugar solution per test tube. We can then identify the balloons by the numbers 2, 5, 10 and 15 corresponding to the increases in volume caused by the addition of the resin in the test tubes. the balloons are carefully capped and then placed in a back-and-forth shaker so that they are uniformly shaken for thirty minutes. The liquid in each flask is filtered through glass wool

tubes are filled to the first mark from the bottom, 'then corked up to this mark. These tables are also labeled 2, 5, 10 and 15 as above.

A series of eleven standard sugar solutions are prepared as below. This series of solutions is only used for one series of determinations.

The solutions used in this standard series are

and these are clogged as we said.

Sample solutions are evaluated by comparison with standard solutions using an ordinary optical comparator. After determining the standard which most closely approximates the color of the sample, the percentage of discoloration is determined by subtracting the percentage. standard of 100% (i.e.% discoloration 100% - standard). This value is then related to the number of milliliters of resin on ordinary graph paper, The amount of resin at the point of discoloration of 50% of the

thus a g / ml bleaching capacity of the sugar of the resin. By applying this method to the determination of the bleaching capacity of sugar, it has been observed that the resins

had a sugar decolorizing capacity often less than 1. By comparison, the resins prepared according to the invention can achieve a sugar decoloring capacity of 4.68 and on average over a large number of operations of about 3, 30, which represents a maximum increase of

It has been noted that the bleaching capacity of the sugar exerted by the resins according to the invention increases regularly with the amount of acetal up to approximately 30% of the weight of the polymer beads. As the quantity of acetal increases further, no comparable increase in deco-decantation capacity is observed.

Polymer beads appear to be a limit beyond which acetal additions are of no economic value.

The resins according to the invention can be regenerated in the same way as before, for example by washing with a solution of sodium chloride or of a strong base such as sodium hydroxide. Thus, in addition to being chemically active, the resins according to the invention have physical characteristics such that they can be used and regenerated repeatedly in. an ordinary water treatment plant.

- ABSTRACT-

A - Process for preparing quaternary ammonium resins; anion exchange, characterized by the following, separately or in combinations:

1 [deg.]) A copolymer of a mixture of a hydro- <EMI ID = 66.1> is treated

in reaction the copolymer thus formed with a tertiary amine, to give a polymeric quaternary ammonium salt;

carbon atoms;

luble suitable for the removal of anions from fluids and in particular colored bodies from sugar solutions, obtained by means of the above process.

<EMI ID = 71.1> of sugar, consisting in bringing said solution into contact with a resin as above.