CA1069247A

CA1069247A - PROCESS FOR AMINATING .alpha.,.beta.-UNSATURATED AMIDE POLYMERS

Info

Publication number: CA1069247A
Application number: CA249,925A
Authority: CA
Inventors: Hiroo Tanaka; Ryoichi Senju
Original assignee: Individual
Current assignee: Individual
Priority date: 1975-04-12
Filing date: 1976-04-09
Publication date: 1980-01-01
Also published as: FR2306999A1; NL158185B; DE2615831A1; FR2306999B1; SE414182B; AU1274676A; DE2615831C2; SE7604217L; NL7603872A; JPS5223661B2; JPS51122188A; GB1518561A

Abstract

ABSTRACT OF THE DISCLOSURE
The present invention provides a process for the Hofmann rearrangement of .alpha.,.beta.-unsaturated amide polymer by haloamidating the .alpha.,.beta.-unsaturated amide polymer with a hypohalite in a medium of aqueous alkali solution and subjecting the result-ing haloamide to rearrangement reaction, characterized by con-ducting the haloamidation reaction at -10 to 10° C and the rearrangement reaction at -10 to 15° C.

Description

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This invention relates to a process ~or the Hofmann rearrangement of~ unsaturated amide polymers under specific conditions and also to the aminated products obtained by the process.
The Hofmann rearrangement is well known which involves the treatment of an amide compound with a hypohalite in an aIkaline medium, followecl by heating to give an amine compound. Polyvinylamine, corresponding to a compound in ~ which the amido groups of polyacrylamide are replaced by ^~ 10 amino groups, is useful as a starting material for various functional high_molecular-weight substances and is also important as a cationic high-molecular-weight coagulant and colloidal titration reagent. Although various attempts have been made to prepare polyvinylamine by the Hofmann rearrangement of polyacrylamide, none achieved a high degree .
~` of amination. Accordingly if it is desired to obtain polyvinylamine of high purity, a very inefficient process must be practiced which comprises the steps of preparing~
vinylurethane as a monomer, polymerizing the vinylurethane and hydrolyzing the resulting polymer to obtain polyvinylamine Generally the Hofmann rearrangement proceeds via~
` the following three steps~

RCONH2 ~ RCONHX - ?~RN=C=O~ RNH2 '~ 25 (I) ~ (III) (IV) 6~4~
The reaction of (II) to (III), which is the rate-determining step, is largely dependent on temperature. In the case of Hofmann rearrang~ment, therefore, it is generally practiced to rapidly heat the reaction mixture to 70 to 90 C
after the completion of the reaction of (I) to (II) so as ` to promote the conversion to (III) and further to (IV).
This procedure is also applied for the Hofmann rearrangement of polyacrylamide. F~r example, Sugiura et al (Kogyo Kagaku Zasshi, 72, 1926 (1969)) recommends the method in which a mixture of polyacrylamide and an alkaline aqueous solution of NaOBr added thereto is reacted at 70 C for 2 hours.
However, our experiments have shown that the degree of - amination achieved by the method is up to 50%.
The low amination degree is attributable to the fact ~`
that the Hofmann rearrangement of polyacrylamide is prone to side reactions which are not encountered with low-molecular~
weight monoamides and other polyvalent amides having no ` ~ proximate amido groups (such as carbamoyl compounds of ~-~ cellulose, starch, etc.)~ The first of the side rêàctions is the formation of urea bonds. Since polyacrylamidé
contalns proximate amido groups, the isocyanate group o~ an intermediate readily reacts with an amino group formed ad~acent thereto, producing a ur~ compound.
C~- CH2- CH- ~ ~ CH-^CH2- CH
N=~O NH2 NH_ ~NH

~:;

~ 3 - ~ - . . . . -: . . - . .- . - .
- . . . ,~ . . . . . .

:10~9~47 This reaction does not occur with low-molecular-uweight monoamides but is very likely to take place with polyacrylamide which contains proximate amido groups.
The second side reaction is the hydrolysis of amido groups with NaOH. Amido groups are readily hydrolyzed with alkali to carboxyl groups. This contributes to the low degree of amination. In order to avoid such hydrolysis, A. M. Schiller et al (Ind. Eng ChemO 2131~
2137 (1956), U.S.P. 2,729,560 (1956)) proposes to conduct the reaction at a reduced temperature of 22 to 35 C. ;
- However7 our experiments reveal that the amination degree ` ~-~
. achieved by this method is still limited to 61%, if highest, presumably because the method is unable to inhibit the urea bondJ although capable of suppressing the hydrolysis of ~ 15 amido groups to some extent.
-~ ~` It is further noted that Sugiura et al and Schlller et al referred to above carry out the reaction at relatively low alkali concentratlon of about 1.5 molesjllter, whereas the ~ide reaction leading to the urea bond can be ;~
inhibited more effectively wlth increasing alkali concentra~
tion, because at ~hi8h alkali concent~rations the isocyanate ;~
resulti~ng from the rearrangement is immediately converted ;;
to~an~amine by alkali. It appears that this conversion takes place in preference to the reaction between the i~30cyanate group and the amino group~ which reaction forms `
the urea bond. ~hus ~he known methods involving low alkali~

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concentrations fail to fully inhibit the urea bond.
In brief, the conventional methods wherein the reaction is conducted at a low alkali concentration as - at about 1.5 moles/liter and at a relatively high temperature of 22 to 35 C or 70 C entail side reactions, giving urea bonds and carboxy:L groups and resulting in low degrees of amination. Notwithstanding that it is theoretically known to prepare polyvinylamine by the Hofmann rearrangement of polyacrylamide, these drawbacks render the process commercially infeasible.
An object of this invention is to provide a process for the Hofmann rearrangement of an~ unsaturated amide - polymer to an aminated product having a desired amino content.
; Another object of this invention is to provide a process for the Hofmann rearrangement of ~ unsaturated ~ amide polymers to aminated products having very high amino ;~ contents.
Other objects and features of this invention will ~` become apparent from the ~ollowing description.
~ ~ 20 The present invention provides a process for the ~ `
`~ ~ Hofmann rearrangement of~ unsaturated amide polymer by haloamidating the d,~-unsaturated amide polymer with a hypohalite in a medium of aqueous alkali solution and ub~ecting the resulting haloamide to rearrangement reaction,`
the process being characterized by conducting the haloamidating reaction at -lO to 10 C and th~ rearrangement reaction at lO to 15 ~

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- -:~6~9L7 We have conducted ex~ensive research on the Hofmann rearrangement reaction with respect -to the influence of the reaction temperature and aIkali concentration on the degree of amination and found that at the same alkali concentration the amination degree increases with decreasing reaction temperature. More specifically we ha~e found that the rearrangement reaction, when conducted at a low temperature ~ of -10 to 15 C, can be conducted almost free of side :~ reactions, with the result that and,~-unsaturated amide 10 polymer can be easily prepared with a desired amino content ~` by suitably controlling an amount of hypohalite. We have further found that the amination degree can be increased to ; : at least 80% or possibly to 95% by conducting the rearrange-ment reaction at an alkali concentration of at least 2 .~- .
moles/liter and at the above-mentioned low temperature.
The degree of amination or amination degree referred to in this invention is defined as the mole % of the formed amino groups based on the hypohalite used f~r the reaction~ :`
However, if the amount of hypohalite used is in excess of . 20- the equivalent of amido groups, the amination degree is defined as the mole % of the formed amino groups based on the amido groups.
The d~-unsaturated amide polymers to be used in this in~ention are known water-soluble polymers, exemplary of which are polyacrylamide, polymethacrylamide and scrylamide-methacrylem1de copolymer. Preferably these ~ ~ :

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polymers may have a number average molecular weight measured by an intrinsic viscosity method of about 5,000 to about 2,000,000, but those having a higher number average molecular weight, e.g. 5,000,000, are usable. Among the d,~-unsaturated amide polymers given abo~e, polyacrylamide is preferable to use.
Examples of hypohalites are alkali metal salts such as sodium salts or potassium salts of hypochlorous acid, hypobromous acid and hypoiodous acid, among which sodium hypochlorite (NaOCl) is preferable.
The aqueous alkali solutions useful as reaction media may be those usually known such as aqueous solutions of aIkali metal hydroxides including sodium hydroxide, potassium hydroxide, etc, When it is d~sired to obtain a product having a high amino content te.g. over 80 mole %), the proportions of the materials to be used are 0.85 to 1.2 equivalents of hypohalite and 1~7 to 20 equivalents, preferably 4 to 15 ~ equivalents~ of alkali based on the amido groups in the `~ 20 d,~-unsaturated amide polymer. A product having a low amino~
content is obtained by using a desired quantity of hypohalite and about 2 equivalents of alkali based on the hypohalite~
; ~ When preparing a product having a high amino content (e~g. over 80 mole %), the reaction proceeds increasingly effectively with the increase in the alkali concentration of the reaction system, Thus it is preferable .. .~ . ~ ,. .

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10~9247 to conduci the rearrangement reaction in the presence of about 2 to about 10 moles of alkali per liter of the system.
At a concentration of less than 2 moles/liter, the reaction proceeds at a low velocity, leading to a low amination degree. Goncentration higher than 10 moles/liter are not desirable, since d,~-unsaturated amide polymer will then be salted out. In view of the amination de~ree, reaction velocity and e~ionomy, an alkali concentration of about 4 to about 8 moles/liter in the reac~ion system is especially preferable. According to this inven-tion, the rearrangement reaction should be conducted pre~erably at a high alkali concentration as described above but the haloamidation reaction may be conducted at a concentration lower than 2 moles!liter. Accordingly the present process can be practiced `~ 15 by conducting the haloamidation reaction at a low alkali concentration and thereafter effecting the rearrangement reaction at a specified higher alkali concentration with the addition of alkali, : ` In this invention the ~p-unsaturated amide polymer and hypohalite are subjected to haloamidating reaction in~
a medium of aqueous~alkali solution generally at a temperature of -lO to 10 C, prafera~ly at -5 to 5 C.
The reaction is~completed in about 30 to about 60 minutes.
Subseguently the re~ction system is maintained at a ~ 25 temperature of -10 to 15 C, preferably 0 to 10 C~ allo~ing ~;~
`'2~ the rearrangament rsaction to proceed to give the desired ~ aminated produot of~d)~-unsaturated amide polyme~

~0~i92~7 The rearrangement reaction is completed in about 1 to about 5 hours. The lower the rearrangement temperature, the lower is the velocity of rearrangement reaction but the higher will be the degree of amination. The Hofmann rearrangement reaction thus conducted at the lowest possible temperature by this invention is entirely contrary to the attempts heretofore made.
For a better understanding of this invention, an experiment is conducted in which polyacrylamide (hereinafter 10- referred to as "PAM") and an equivalent of sodium hypochlorite based on amido groups of the former are reacted in an aqueous;
- aIkaline medium containing 5.0 moles of NaOH per liter of the reaction system first at -5 C for 30 minu-tes, the - reaction mixture being thereafter maintained at 0 C for the rearrangement reaction (see Example 1)~ Fig. 1 gives a graph sho~ving changes in the degree o~ amination of PAM due to the rearrangement with the lapse of time, Fig. 1 indicates that about 50% of amination is effected at -5 C in 30 minutes and that the amination degree reacheis as high as 93% at oC ;
" ~ 20 in 180 minutesO It is seen that the Hofmann rearrangement of PAM, unlike that of other low-molecular-weight amide compounds, readily proceeds at a low temperature of 0 C, This is in no way conceivable from the usual concept of Hofmann rearrangement but is a p~culiar phenomenon achieved by this in~ention With use of P~M and d~-unsaturated amide poly~ers usable in the in~ention.

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, . ` ' ' ` ` ` ' ' ' 92~7 Figs. 2 and 3 give graphs showing the amination degrees, decrease of chloroamido groups an~ yield of other by-product groups (chiefly urea bonds) achieved when PAM
and sodium hypochlorite are completely reacted for rearrange-ment at 0 C at varying NaOH concentrations (see Example 12).
Fig. 2 reveals that the higher the alkali concentration, the higher is the amination degree and, conversely, the lower the yield of other by-product groups (mainly urea bonds). Fig. 3 shows that the higher the alkali concent-ration3 the greater is the decrease of chloroamido groups.
According to this invention, the reaction is terminated by neutralizing the reaction mixture with an acid such as hydrochloric acid, sulfuric acid or phosphoric acid, whereby the resulting aminated product is converted to a salt of such acid. When required, the remaining hypohallt e and haloamido groups may be reduced, before or after the ~ ~ neutralization, with a reducing agent such as sodium thiosulfate,- sodium bisulfite or the like; The neutralized reaction mixture is poured into a water-soluble organic solvent such as acetone~ methanol or dioxane in an amount of 5 to 20 times the volume of the mixture to precipitate the neutralized product. The preclpitate, which still contains small amounts ~ -of inorganic salts, may preferably be purified by repeating the procedure of dissolving and precipita-tion. When ;
recovering the reao~ product as a free amine, the reaction mixture may be poured, without neutralization, directly into : . ~ ....

:L~69~47 the above-mentioned water-soluble organic solvent for precipitation, whereupon the reaction is terminated.
The aminating process of this invention in which side reaction are almost inhibited easily gives aminated products of d,~ -unsaturated amide polymers with high degrees of amination.
The usefulness of this invention is most manifest when partially aminating d ~-unsaturated amide polymers, with some of the amido groups therein left unreacted.
When an equivalent or more of hypohalite is ùsed based on - the amido groups, these groups are subjected to haloamidation ` in preference to hydrolysis with alkali and are therefore ~; free of hydrolysis. In respect of side reactions, therefore precautions may be taken only against the formation of urea bonds. Howe~er, if less than an equivalent, for example ` 30 mole %, of hypohalite is used for partial amination, : .
70 mole % of amido groups will be exposed to hydrolysis wikh~
alkali. If the reaction is then carried out at a high temperature~ the remaining 70 mole % of amido groups would ~ ~ 20 be hydrolized with alkali to carboxyl groups. In an ;~ extreme case, PAM would be converted even to polyacrylic acld.
When the reaction is effected at a low temperature as in this invention, most of the remaining amido groups `~
.. ..
can be left intact. It is indeed no exaggeration to say `25 that partially aminated ~ unsaturated amide polymers can be prepared only b~ the proces~ of this in~ention. ;

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~6~2~7 This invention is of immense significance since the partially aminated PAM is already evaluated as an ideal paper reinforcing agent conjointly containing amino groups and amido groups.
Given below are Examples o~ this invention, in which the reaction products are analyzed by the following methods.
-For analysis, about 3 g of the reaction mixture is ` weighed out and diluted with ice water (0 to 2 C) to prepare a 200 ml of sample.
` (a) Quantitative analysis of chloroamido groups `-` A 10 ml quantity of 2% aqueous dispersion ofdiethyl malonate (0 C) is added to 50 ml of the sample, and the mixture is stirred. Immediately thereafter, a ~ ~ 15 mixture of 10 ml of 10% aqueous KI solution and 5 ml o~ acetic i ~ acid is added to thè resulting mixture, and the mixture obtained is allowed to stand at a cool dark place for lO mlnutes.
` ~ The mixture is then titrated~with a 0.02N aqueous solution~
of sodium thiosulfate.
(b) ~uantitati~e analysis of amino groups A 50 ml quantity of the sample is slightly acidified~
with dilute hydrochloric acid and colored with 1 or 2 droplets~
of 10% solution of KI. Finely divided NaHS03 is added in mall portions to the sample until the color disappears.
`25 A lO ml portion~of the colorless sample is diluted with lO0 ml o~ cold water and the mixtura is then ad~usted Witjh ~ ;

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: ~ - . . . , ~ .. , - ~ , . ... . -, . . .

~i9247 dilute hydrochloric acid to a pH of about 2 and titrated with a 0.0025N aqueous solution of potassium polyvinyl sulfate~
(c) Quantitative analysis of carboxyl groups A 50 ml quantity of the sample is slightly acidified with dilute hydrochloric acid and colored with 1 or 2 droplets ~ of 10% solution of KI. Finely di~ided NaHS03 is added in ; small portions to the sample until the color disappear90 ;~ A 10 ml portion of the colorless sample is diluted with 100 ml of cold water, and the mixture is adiusted to a pH of 11.5 to 12.0 with a 0.5N aqueous solution of NaOH. A 5 ml quantity of 0.005N aqueous solution of Polyaminesulfon (trade mark for a cyclic copolymer of dimethyldiallyl ammonium chloride and sulfur dioxide, product of Nitto Boseki Co., Ltd., Japan) is added to the resulting solution, and the ~ ~ -mix~ure is titrated with an aqueous solution of 0.0~25N ;~
potassium polyvinyl sulfate.

A mixture of 6.0 ml of aqueous NaOCl solution with a concentration of 2.27 moles/liter and 8.0 ml of aqueous NaOH solution with a concentration of 15 moles/liter is placed ln a 100-ml beaker and cooled to -20 C with a . ~
refrigerant, A 10 g quantity of 10 wt. % aqueous solution of PAM (molecular weight: 470,000) is added to the mi~ture ;~
with thorough stirring~ Care should be t~ken to maintaln Z5 the reaction system at a temperature of -5 C for 30 minutes with sufficient cooling, overcoming the generation of heat, ` ~ 13 -: ~ ~

IL~69247 The reac~tion temperature is thereafter allowed to slowly rise to 0 C to continue the reaction at this temperature.
The reaction is completed in 180 minutes. The NaOH
concentration of the reaction system is 5.0 moles/liter, and the amination degree 93%.
~hen the resulting reaction mixture is poured into 150 ml of methanol, a precipitate is formed. The ~` precipitate is filtered off and dissolved in 10 ml of water.The solution is acidified with dilute hydrochloric acid and then poured into 100 ml of methanol. The precipitate - formed is filtered off, washed with methanol and dried, giving 1.05 g of white deliquescent powder.

:
In the same ~anner as in Example 1, 6.0 ml of ~ ~-aqueous NaOCl solution with a concentration of 2.27 moles/liter~, -6.0 ml of aqueous NaOH solution with a concentration of 15 moles/liter and 10 g of 10 wt. % aqueous solution of PAM
(molecular weight: 470~000) a~re reacted. The NaOH concentration ~` of the reaction system is 4.1 moles/liter and the amination ;~ 20 degree 90%.
`~` EXAMPLE ~
` ~ Th~ same procedure as in Example 2 is repeated except that 14 ml of water is added to the mixture of NaOCl ~ and NaOH solutions. The NaOH cohcentration of the reactlon `~ ~; system 1s 2.5 moles/liter and the amination degree 82%. .

. . , .: . .. . , . , . ... ,. . . - . . ..

4 ~
EXAMPLES 4 to 6 The same procedure as in Example 2 is repeated except that the reaction temperatures and reaction times are as follows.
Example Chloroamidation reaction Rearrangement reaction 4-5 C 30 min 5o C 120 min The same procedure as in Example 6 is repeated ~ except that the rearrangement reaction is conducted at 20 C
`~ for 120 minutes. The aminàtion degree is 63%.

`The same procedure as in Comparison Example 1 is `~ 15 repeated ~except that NaOCl, NaOH and PAM are reacted at

2 C for 15 minutes, then heated to 70 C over a period of `
30 minutes and thereafter reacted at this temperature -for ;
:
2 hours. The amination degree is 55%
COMPARISON EXAMPLE ~
~;~ 20 ~ The same procedure as in Comparison Example 2 is ~, repeated except that 38 ml of water is added to the mixture of NaOCl, NaOH and PAU. The NaOH concentration of the ;~
reaotion sy8tem i8 1.5 moles/liter and ~he aminatlon degree ` is 45%.

A 6.0 ml qUantity of aq~eous NaQCl soIution with ~` a concentrat;ion of 2.27 moles/liter and 6.0 ml of aqueous ~, ~

~ ~69~7 NaOH solution with a concentration of 1~ moles/liter are placed into a beaker and heated to 22 C. A 10 g quantity of 10 wt. /0 aqueous solution of PAM (molecular weight: 470,000) is added in small portions to the mixture with full stirring. The mixture, which evolves heat, is reacted with cooling for 60 minutes while maintaining the reaction temperature at al~out 22 C. The N~OH con-centration o~ the reaction system is 4.1 moles/liter and the amination degree is 61%.

A 6.0 ml quantity of aqueous NaOCl solution with a concentration of 2.27 moles/liter, 3 3 ml of aqueous NaOH solution with a concentration of 15 moles/liter and 23 ml of water are placed in a beaker and heated to 22 C.
Subsequently the same procedure as in Comparison Example 4 is repeated. The NaOH concentration of the reaction system is 1.5 moles/liter and the amination degree is 47/00 COMPA~ISON EXAMPLE 6 A 1.11 ml quantity of aqueous NaOCl solution with a concentration of 1.9 moles/lit~ and 0.42 ml of aqueous NaOH solution with a concentration of 10 moles~liter are heated~to 22 C. A 5.0 g quantit~ of 10 wt. % aqueous solution of PAM tmolecular weight: 470,000) is added in small ;
portions to the mixture. The proportion o~ NaOCl used based on the amido groups i8 30 mole %, and the NaOH concentration of the reaGtion system is 0.65 mole/liter. The mixture, which ~. ...

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evolves heat, is cooled to maintain the reaction temperature at about 22 C. The reaction is completed in L~O minutesO
The reaction product is found to contain 5.7% o~ amino groups and 40% of carboxyl groups. Thus only 19% o~ the NaOCl (30 mole %) used acts effectively for the formation of the amine. The carboxyl content indicates that 57% of the amido groups (70%~, which are not chloroamidated, are hydrolyzed with alkali, giving 40% of carboxyl groups.

The same mixture of NaOCl and NaOH solutions as used in Comparison Example 6 is cooled to -10 C. A 5.0 g quantity of 10 wt. % aqueous PAM solution is added to the mixturè. The mole ratio of the amido groups: NaOCl : NaOH
is 1 : 0.3 ~ 0.6. The mixture, which evolves heat, is reacted at 0 C for 30 minutes ~ith coolingO The mixture is thereafter slowly heated and reacted at 4 to 7 C for 3 hours.
` The resulting product is found to contain 22% of amino groups. This indicates that.a high amination degree of 75%
is achieved based on the NaOCl (30 mole %~ used. The ` 20 carboxyl content, which corresponds to 10% of the total amidogroups, reveals that only 15% of the amido groups (70/o),~
which are not chloroamidated, are hydrolyzed.
XAMPLE 8 ~ ;
~ ~ ~ The same procedure as in Example 1 is repeated `;~ 25 except that 12 g of 10 w-t. % aqueous solution o~ polymethacryl-~: .
~; amide (molecular weight: 51~000) is used in place of PAM. ~ ~ ~
~ ~ :

~ 17 ~ ~

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.: . . . : . . : : - .. . . . . . .. . : -- - ~ C)69~47 The NaOH concentration of the reaction s~stem is 4.6 moles/liter and the amination degree 91%.

A mixture of 6.0 ml of aqueous NaOCl solution with a concentration o~ 2.8 moles/liter and 3.0 ml of aqueous NaOH solution with a concentration o~ 5.6 moles/liter is placed in a 100-ml beaker and cooled to -10 C with a refrigerant. A 11.6 g quantity of 10 w-t. % aqueous solution of PAM (molecular weight: 1,020,000) is added to the mixture with full stirring at a temperature of up to -5 C. After maintaining the resulting mixture at -5 C
for 20 minutes, 15.2 ml of aqueous NaOH solution with a concentration of 15 moles/liter is added to the mixture.
This raises the temperature to 0 C. The mixture is ;; 15 maintained at this temperature for 120 minutes, whereby the reaction is completed. The NaOH concentration of the reaction system is 7.0 moles/liter and the amination degree 95%.
EXAMPLE 10 ; `
The same procedure as in Example 9 is repeated~
except that the temperature is maintained at 0 C or lower when PAM i9 added and i9 allowed t~o reach 10 C when the additional NaOH solution is added. The amination degree ~;
. ~
i9 86%.

A mixture of 6.0 ml o~ aqueous NaOC1 solution with a concentration of 2.8 moles/liter and 3.0 ml oE ;

- 18 ~

:~L06924~

aqueous NaOH solution with a concentration of 5.6 moles/liter is placed in a 100-ml beaker and cooled to -5 C. A 11.6 g quantity of lOwt. % aqueous solution of PAM (molecular weight:
1,020,000) is added to the mixture with full stirring at a temperature of up to 0 C. After maintaining the resulting mixture at 0 C for 20 minutes, 11.3 ml of aqueous NaOH
solution with a concentration of 15 moles/liter is added to the mixture, allowing the temperature -to reach 10 C.
The resu~ting NaOH concentration of the reaction system . is 6.0 moles/liter. The mixture is thereafter ~aintained at the same temperature for 120 minutes, whereby the reaction . is completed. The amination degree is 84%.
- Table 1 shows the reaction conditions of Examples 1 to 11 and Comparison Examples 1 to 6, and Table 2 gives the results obtainsd by aralyzing the reacti~n product6.

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-~069~'7 Table 1 .
Chloroamidation Rearragement CONH2:NaOCl: NaOH concn.
reaction reaction NaOH (mole (moles/Q ) C min C min ratio) 5Ex, 1 -5 30 0 180 1:1:8.8 5.0 2 " ll w w 1:1:6.4 L~.l

3 " " " " " 2,5

4 ~ 5 120 1:1:6.4 4.1 ` 5 " " 10 100 ; " "
6 0 ~' 15 " " "
. Comp.
Ex. 1 il w 20 120 . . 2 2 15 7~ 120 " 11 3 " " 11 11 " 1.5 .:
4 22 - 22 60 " 4.1 ~ _ ll ll 1:1:3.5 1.5 ~: 6 " - " L~O1:0.3:0.6 0.65 ~ :, , Ex. 7 0 30 4-7 180 " 1l ~. .
8 ~5 ~' o 1l, 1:1:808 4.6 ~ ` 20 ~ w 20 ~ 120 1:1:15 7.0 '^-~ , 10 0 " 10 1' 'I ~I : ~ . ',;
~ 11.4 6.o -~: ' ~; ,., : : :`

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, f~9~4~7 Table 2 Amination -COOH Amido group Others de~ree (%) (mole %) (mole %) (mole %) Ex. 1 93 5 _ 2 3 82 7 _ 11 84 7 ~ 9 : 6 70 10 ; - 20 10Comp.
- Ex. 1 63 11 - 26 2 55 17 - 28 ~ :
3 45 22 _ 33 ~ .
- L~ 61 13 - 26 L~7 2L~ _ 29 6 19(5.7)* L~O 28 26 Ex. 7 75(22)* 10 60 . 8 9 95 3 - . 2 86 : 6 - 8 :
: 11 84 6 - 10 ` ~ :
Mole % of amino groups~

PAM (molecular weight: 100,000), NaOCl and NaOH
r ~
in the CONH2: NaOCl : NaOH mole ratio of 1 ; 1 : 5 are maintained.at -5 C ~or 30 minutes and thereafter at 0 C
for reactionO Fi~s. 2 and 3 show the results of reactlon 21 ~

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at varying NaOH concentrations. In Figso 2 and 3, curves A, B and C represent amination degrees, curves Al, Bl and C~ the yields o~ other by-product groups tmainly urea bonds) and curves A" , B" and C" the yields of chloroamido groups. Further the curves A, Al and A~' represent the results ~Yhen the.NaOH concentration of the reaction system is 5.0 moles/liter, the curves B, Bl and Bll those Yihen the NaOH concentration is 2.5 moles/liter and the curves C, C~ and C~ hen the NaOH concentration is 1.5 moles/liter.
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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the Hofmann rearrangement of .alpha.,.beta.-unsaturated amide polymer by haloamidating the .alpha.,.beta.-unsaturated amide polymer with a hypohalite in a medium of aqueous alkali solution and subjecting the resulting haloamide to rearrange-ment reaction, characterized by conducting the haloamidation reaction at -10 to 10°C and the rearrangement reaction at -10 to 15°C.

2. A process as defined in claim 1 wherein the .alpha.,.beta.-unsaturated amide polymer is one species selected from the group consisting of polyacrylamide, polymethacrylamide and acrylamide-methacrylamide copolymer.

3. A process as defined in claim 2 wherein the .alpha.,.beta.-unsaturated amide polymer is polyacrylamide.

4. A process as defined in claim 1 wherein the .alpha.,.beta.-unsaturated amide polymer has a number average molecular weight of 5,000 to 5,000,000.

5. A process as defined in claim 4 wherein the number average molecular weight is 5,000 to 2,000,000.

6. A process as defined in claim 1 wherein the hypo-halite is an alkali metal salt of hypochlorous acid, hypo-bromous acid or hypoiodous acid.

7. A process as defined in claim 6 wherein the alkali metal salt is a sodium salt or potassium salt.

8. A process as defined in claim 7 wherein the hypo-halite is sodium hypochlorite.

9. A process as defined in claim 1 wherein the aqueous alkali solution is an aqueous solution of alkali metal hydroxide.

10. A process as defined in claim 9 wherein the alkali metal hydroxide is sodium hydroxide or potassium hydroxide.

11. A process as defined in claim 1 wherein the rearrangement reaction is conducted in a medium of aqueous alkali solution, the alkali concentration of the reaction system being 2 to 10 moles/liter.

12. A process as defined in claim 11 wherein the alkali concentration of the reaction system is 4 to 8 moles/liter.

13. A process as defined in claim 1 wherein the halo-amidation reaction is conducted at -5 to 5°C.

14. A process as defined in claim 1 wherein the rearrangement reaction is conducted at 0 to 10°C.

15. A process as defined in claim 1 wherein the halo-amidation reaction is conducted at -5 to 5°C and the rearrange-ment reaction is conducted at 0 to 10°C.