Hoechst Aktiengesellschaft

Lothar Brandt

Arno Holst

Utz-Hellmuth Felcht

Hans-Jerg Kleiner

The novel water-soluble compounds are the ethyl ether and the N,N-dialkyl(C.sub.1 to C.sub.4)aminoethyl ethers of .beta.-cyclodextrin (.beta.-CD). The process for the preparation of these ethers is performed by reacting .beta.-CD with an etherifying agent in a basic liquid reaction medium. The reaction medium contains an alkali-metal hydroxide, water and at least one water-miscible organic solvent (for example, dimethoxyethane or isopropanol).

Ethers of beta-cyclodextrin and a process for their preparation

The invention relates to novel water-soluble mixed ethers of .beta.-cyclodextrin (.beta.-CD) with ether substituents comprising (C.sub.1 and C.sub.2) alkyl, hydroxy(C.sub.2 to C.sub.4)alkyl and carboxy(C.sub.1 and C.sub.2)alkyl such as methylhydroxyethyl-.beta.-CD or hydroxyethyl-carboxy-methyl-.beta.-CD; hydroxyethyl-hydroxy propyl ethers are excepted. The process of the invention comprises reacting .beta.-cyclodextrin with at least two different alkylating, hydroxyalkylating and/or carboxyalkylating etherifying agents (for example, methyl chloride, ethylene oxide and/or chloroacetic acid) in a basic, liquid reaction medium containing an alkali-metal hydroxide, water and, optionally, at least one organic solvent (for example, dimethoxyethane or isopropanol).

Water-soluble mixed ethers of .beta.-cyclodextrin and a process for

Disclosed is a cellulose ether having at least one phosphorus-containing substituent or a mixed ether of said cellulose ether having in addition at least one phosphorus-free substituent comprising alkyl, hydroxyalkyl, carboxyalkyl, sulfonoalkyl, aminoalkyl, or diaminoalkyl, wherein the phosphorus-containing substituent(s) comprise(s) groups of the formula ##STR1## wherein R.sup.1 and R.sup.2 are OX; or R.sup.1 is OX and R.sup.2 is OY; or R.sup.1 is OX and R.sup.2 is (CH.sub.2).sub.n --CH.sub.3 ; or R.sup.1 and R.sup.2 are (CH.sub.2).sub.n --CH.sub.3 ; or R.sup.1 is (CH.sub.2).sub.n --CH.sub.3 and R.sup.2 is (CH.sub.2).sub.p --CH.sub.3, wherein

Cellulose ethers and cellulose mixed ethers having at least one

The application discloses a gel-forming composition based on (a) water, (b) a water-soluble cellulose mixed ether having at least one nonionic substituent from the group comprising hydroxyalkyl and alkyl and at least one anionic phosphorus-containing substituent, and (c) a salt containing a cation which is at least divalent. The phosphorus-containing substituent is a phosphonoalkyl group or a p-alkylphosphinoalkyl group. The application also relates to a process for the preparation of a gel from this composition, to the reversible reversing of the gel by the addition of an agent which complexes the cation, e.g. in the case of Al.sup.3+ ions, Fe.sup.3+ ions, Zr.sup.4+ ions or ZrO.sup.2+ ions, by means of an amount of fluoride ions, and to the use of this gel-forming compostion in the secondary production of petroleum.

Cellulose ether-based gel-forming composition and methods of use and

Disclosed is a process for preparing water-soluble phosphonomethyl ethers of cellulose from cellulose and halogenomethane phosphonic acid or one of its salts or acid derivatives, in an aqueous, alkaline medium. The process is carried out in such a way that, for each mole of the cellulose, from about 2.1 to 15 moles of hydroxide ions and from about 0.4 to 3.0 moles of halogenomethane phosphonate ions as etherifying agent are caused to react in from about 3 to 50 parts by weight, per part by weight of the cellulose, of a mixture which is composed of an inert, preferably water-miscible organic solvent and water and in which the proportion of water ranges from about 2 to 60 percent by weight, the reaction is continued until the phosphonomethyl cellulose has a DS of at least about 0.13.

Process for preparing water-soluble phosphonomethyl ethers of cellulose

Disclosed are water-soluble cellulose mixed ethers which contain (a) at least one substituent from the group comprising alkyl, hydroxyalkyl, carboxyalkyl, sulfoalkyl and dialkylaminoalkyl and (b) a phosphonomethyl substituent and which has a DS of the first substituent(s) other than hydroxyalkyl from about 0.05 to 2.95 and/or an MS.sub.HAlk from about 0.5 to 6 and a DS.sub.PM from about 0.005 to 0.8. Also disclosed is a process for preparing such cellulose mixed ethers in which, per mole of the cellulose, from about 0.1 to 25 moles of the etherifying agent(s) for producing the substituent(s) under (a), from about 0.05 to 2 moles of halogenomethane phosphonate ions as the etherifying agent for producing the substituent under (b) and from about 0.8 to 12 moles of hydroxide ions are caused to react in a reaction mixture comprising up to about 30 parts by weight, per part by weight of the cellulose, of a mixture which is composed of an inert, preferably water-miscible organic solvent and H.sub.2 O and in which the proportion of water ranges from about 3 to 40 percent by weight.

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Wiesbaden, Germany

Lothar Brandt