1991, 6, 800‐806. The amphoteric acrylamide-derived (co) polymer thus produced has a bulk viscosity of 38 cps (at 25 ° C., Brookfield LV1, 60 rpm), a concentration of 10% and also satisfies the stability test as set forth in US Pat. ES, Kind code of ref document: Novel method for preparing acrylamide copolymers by hofmann degradation reaction Download PDF Info Publication number EP2352770B1. A solution of hypohalide and alkali and / or alkaline earth hydroxide is then prepared from the alpha and beta ratios. By way of examples, the additives in question may therefore be of the family: alcohols, polyols (eg: starch), polyamines, polyethylene imines ... Before being degraded, according to the invention is incorporated in the copolymer base solution one (or more) polyvalent cationic ion salt (ie cationic charge greater than or equal to 2) and this, at a minimum concentration of 0 , 5% by weight, preferably 2 to 10% by weight, based on the (co) polymer base. Use the link below to share a full-text version of this article with your friends and colleagues. Learn about our remote access options, (Research Laboratory of the N.V. Koninklijke Pharmaceutische Fabrieken v/h Brocades‐Stheeman & Pharmacia, Amsterdam; Chemical Laboratory of the “Vrije Universiteit”, Amsterdam). The branching may preferably be carried out during (or possibly after) the polymerization of the "base" copolymer, in the presence of a polyfunctional branching agent and optionally of a transfer agent. LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT, Free format text: List of Name Reaction of Organic Chemistry consist of detail Reaction Mechanism of all name reactions of Organic Chemistry. The following examples illustrate the invention without, however, limiting its scope. EP2352770B1 EP20090828704 EP09828704A EP2352770B1 EP 2352770 B1 EP2352770 B1 EP 2352770B1 EP 20090828704 EP20090828704 EP 20090828704 EP 09828704 A EP09828704 A EP 09828704A EP 2352770 B1 EP2352770 B1 EP 2352770B1 Org. Examples of the cationic acrylamide polymers known in the prior art are of different types: it is most commonly acrylamide co-polymers and cationic monomers, it can also be polymers known as Mannich ( the acrylamide polymer reacts with formaldehyde and a secondary amine and is then quaternized), glyoxalated polymers or acrylamide polymers on which Hofmann degradation has been carried out. 602009031155, Country of ref document: Reaction Scheme • First published 1881 Hofmann, A. W. Chem. LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES, Free format text: 15(4), 333-335 (1992) Practical Hofmann Rearrangement Sang-sup Jew*, Hyeung Geun Park, Myoung-hee Kang Tae-hee Lee and Youn-sang Cho Col~ego of Pharmacy, Seoul Nationa/ Universi~ San 56-1, Shlh//m-Dong, Kwanak-Ku, Seou/ 151-742, Korea (Received October 6, 1992) Abstract [] Hofmann rearrangement of a series of primary aliphatic and aromatic carboxamides la-lm with HgO … �0I�4�꒬PY����\%��!S`�t Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username, By continuing to browse this site, you agree to its use of cookies as described in our, I have read and accept the Wiley Online Library Terms and Conditions of Use. Of all these polymers, only those obtained by Hofmann degradation reaction have specific properties that are not shared in terms of cationic charge density. In practice, the base polymer used consists of: Advantageously, the base polymer is preferably composed of: It is important to note that, in combination with these monomers, it is also possible to use water-insoluble monomers such as acrylic, allylic or vinyl monomers having a hydrophobic group. Shioiri, T. Comp. Reaction Scheme • First published 1881 Hofmann, A. W. Chem. Working off-campus? These are: - Alpha = (alkaline and / or alkaline earth / acrylamide hypohalide) and - Beta = (alkali and / or alkaline earth hydroxide / alkaline and / or alkaline earth hypohalide). And / or a nonionic monomer preferably chosen from the group comprising N-vinyl acetamide, N-vinyl formamide, N-vinylpyrrolidone and / or vinyl acetate. According to the invention, the reagents preferably used are sodium hypochlorite (bleach) and sodium hydroxide (sodium hydroxide). Hofmann elimination (Eq. Res. Please check your email for instructions on resetting your password. The invention relates to an improved process for preparing cationic or amphoteric acrylamide (co) polymers. The problem to be solved by the invention is therefore to propose an improved process for the preparation of cationic or amphoteric acrylamide (co) polymers while preserving their stability and high molecular weight characteristics in polymer audits. DE, Ref document number: The Applicant has found and developed a process for the preparation of cationic or amphoteric (co) polymers derived from acrylamide by a so-called Hofmann degradation reaction in aqueous solution in the presence of an alkali and / or alkaline hydroxide. ammonium. This reaction occurs in a special rearrangement mechanism. all rights reserved. 23.33). Arch. Even though these products are known in the prior art for their instability at Alpha coefficients of less than 1, it could not be presumed that the mere introduction of a polyvalent cationic ion salt could confer on the cationic (co) polymer. Under these conditions, the solid form contains not only the copolymer, but also a small proportion of salt obtained at the end of the hofmann degradation reaction. Res. B1, Free format text: If you do not receive an email within 10 minutes, your email address may not be registered, According to Rodionow and Fedorowa1), Hofmann degradation of 4‐hydroxy‐phthalimide yields 2‐amino‐4‐hydroxy‐benzoic acid. These salts are preferably in the form of halide, sulfate, carbonate, nitrate, phosphate, nitrite, citrate or acetate. :��n�)*���8�KP�눽u|����ȝ&X��~�U'�mW�{]M���j�W��5��&�ٲ���l{o�#o�tv�>���W��M��j��x��O7͠`��>?����
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1w(c�P��9(*2���(cv8�(����yJ5ⴿO��r�9b��w2�F㲙ow',Q1ef�j���҈-Kj�ۉҩ�n~O��4@U�di��,�ٺ��q�'�3:���3�tQ�t�M( ��&��9Y���XN���dCʰ�y�����a��z;������miȶ��
r��a@>c�c���}UOc�#_��C5ݺi���6K�S�2=��F� 9�r@Z�'P����n��L~���>/������E�FB�d$:t2.��t��B��4#e���F֓\ț���H���}�m#���E�<7�����F��.^8N���L2h. Until recently, only very heavy processes using, in situ, a Hofmann degradation product manufacturing unit (, It was not until early 2005 and the patent. … The copolymer serving as a basis for the Hofmann degradation reaction does not require the development of a particular polymerization process. Presentation (PDF Available) ... Hofmann degradation: The Hofmann degradation is the organ ic reaction of a . Reaction Mechanism of Hoffmann Bromamide Degradation The reaction mechanism involves base-promoted N-bromination yielding N-bromo amide as an intermediate. Only 2‐amino‐5‐hydroxy‐benzoic acid could be isolated from the reaction mixture. Hofmann rearrangements, such as those generating the first two products shown in Figure 3.17, can efficiently prepare some hindered amines. In general, it is known that to be effective as a resistance agent, the (co) polymers used must be in the most cationic form possible and therefore have a high degree of degradation. AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR, Kind code of ref document: KOH and Br2are also used as reagents. 9.5), in which a proton and a halide ion are eliminated; in the Hofmann elimination, a proton and a tertiary amine are eliminated. After chlorination using 1,3,5-trichloroisocyanuric acid (TCCA), conversion to the isocyanate took place with heating, and the latter was trapped with MeOH [82]. Shioiri, T. Comp. This base is characterized in that it has a molecular weight greater than 5000 g / mol and without any maximum limitation. A process for preparing cationic or amphoteric (co)polymers derived from acrylamide by a degradation reaction called a Hofinann degradation in aqueous solution in the presence of an alkali and/or alkaline-earth metal hydroxide and an alkali metal hypohalide on a base copolymer. coagulation. The heat is needed for this reaction and in some cases cyanate is also formed. Base catalysed hydrolysis of isocyanate formed in the reaction mixture produces carbamate ion, which undergoes spontaneous decarboxylation resulting in the formation of amine. Sometimes referred to as the Hofmann Degradation. The reaction begins with deprotonation of the amide by the base to form an anion which then attacks the halogen to form a N-haloamide. Furthermore, it is known that when the product obtained by Hofmann degradation reaction is amphoteric, it can also be used to improve the retention of charge during the manufacture of paper or board. In general, these are molecules bearing nucleophilic chemical functions such as hydroxyl or amine functions. Ber. Indeed, depending on the degree of degradation Alpha, it is possible to generate cationicity variations related to the amount of amine functions produced on the carbon skeleton of the (co) polymer. And / or an anionic monomer of the acid or anhydride type chosen from the group comprising (meth) acrylic acid, acrylamidomethylpropanesulphonic acid, itaconic acid, maleic anhydride, maleic acid and methallyl acid. The increase in cationicity of the base copolymer takes place during the so-called Hofmann degradation, by the use, entirely or not, of an alkaline hypohalide. AT, Kind code of ref document: Hofmann rearrangement Last updated; Save as PDF Page ID 15634; Contributors; Hofmann rearrangement, also known as Hofmann degradation and not to be confused with Hofmann elimination, is the reaction of a primary amide with a halogen (chlorine or bromine) in strongly basic (sodium or potassium hydroxide) aqueous medium, which converts the amide to a primary amine. Kind code of ref document: For the conversion of all or part of the amide functions of an acrylamide (co) polymer to amine function, two main factors occur (expressed in molar ratios). Similarly, although prepared in solution, the polymers of the invention may also be provided in solid form. 725667, Country of ref document: A1, Designated state(s): Important Questions CBSE Class 10 Science. In a non-preferred variant of the invention, the incorporation of these salts can also take place before or during polymerization of the (co) polymer base. sulfonic acid, vinyl sulfonic acid and their salt <50 mol%. Advantageously, the branching agent is methylenebisacrylamide (MBA). ⪠one cationic unsaturated ethylenic monomer, selected from the group comprising monomers of the dialkylaminoalkyl (meth)acrylamide, diallylamine, methyldiallylamine type, and quaternary ammonium or acid salts thereof. The acrylamide-derived cationic (co) polymer thus produced has a bulk viscosity of 85cps (at 25 ° C, Brookfield LV1, 60 rpm) and a concentration of 10%. - at least one non-ionic monomer selected from the group comprising acrylamide (and/or methacrylamide), N,N dimethylacrylamide and/or acrylonitrile. This reaction should be done in alkali medium. Amides with no substituent on the nitrogen when treated with a solution of Br2 or Cl2 in KOH yield only primary amines having one carbon atom less than the amides. 1991, 6, 800‐806. LANGUAGE OF EP DOCUMENT: FRENCH, Ref document number: The Hofmann elimination is conceptually analogous to the E2 reaction of alkyl halides (Sec. The main insulation techniques then used are those of spray drying (which consists in creating a cloud fine droplets in a hot gas stream for a controlled time), drum drying, fluidized bed dryers ... As already stated, the copolymers obtained according to the process of the invention find a more specific application in papermaking processes for their drip property, charge retention and / or to improve the dry strength performance. Example 1. Syn. Pharm. Ber. and you may need to create a new Wiley Online Library account. According to another characteristic, the Hofmann degradation product is produced at a concentration greater than 4% by weight, preferably greater than 8%, advantageously greater than 9%. The full text of this article hosted at iucr.org is unavailable due to technical difficulties.
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