Patent GB-972159-A (GB)
Title: Parchment ion exchange reagents
IPC: B01D15/04
Filed: 1962-06-18
Abstract: A parchment ion exchange reagent comprises an esterified or etherified parchment, having, if the reagent contains phosphorus or sulphur, a maximum of 1% combined nitrogen and having a weight ratio of phosphorus to nitrogen, if the reagent contains phosphorus, or of sulphur to nitrogen, if the reagent contains sulphur, of at least 4 to 1. Preferred reagents are parchment carboxy-alkylates, parchment carboxyacylates, parchment phosphoric acid esters and sulphuric acid esters, alkali or alkaline earth metal salts of any of these, parchment aminoacylates and parchment aminoalkylates, the reagents having an ion exchange capacity of 0.3-3 milliequivalents per gram, preferably 0.4-2.7 m.e.g. and especially 0.6-2.5 m.e.g. The parchment treated and the reagent produced may be in sheet form, friable when dry into discrete particulate form, or may be friated into said form, the particles passing a 5 mesh screen (U.S. Standard Series) and preferably being from 10-200 mesh, especially 20-200 mesh. Alternatively, cellulose fibres or flocs, rather than sheets, may be parchmentized and treated to obtain an ion-exchange reagent of very fine particulate form. Specified reagents are parchment carboxyacetate, carboxymethylate, sodium carboxymethylate, succinate, succinate sodium salt, parchment orthophosphoric acid ester, salts of any of these, parchment aminoethylate and parchment aminoacetate. As well as the succinate, parchment phthalate, fumarate, oxalate, camphorate, adipate, itaconate, suberate, malate, citrate and mellitate may be made, and in addition to the aminoacetate and aminoethylate parchment carbamate, a -aminopropionate, a -aminobutyrate, a -amino -b - phenylpropionate, a -aminosuccinate, a -e -diaminocaproate, a -amino -b - imidazolepropionate and corresponding b -amino and secondary and tertiary amino products, dimethyl aminoethylate, diethylaminoethylate, and diisopropylaminoethylate may be made. Parchment may be treated with an esterifying or etherifying agent to introduce chemically attached groups having ion exchange characteriztics into the parchment molecule, and the product washed with a solution of a non-ammonium electrolyte to produce a product having a maximum of 1% combined nitrogen by weight, and where applicable, the stated ratio of sulphur to nitrogen or phosphorus to nitrogen. The parchment may be dried before the washing with electrolyte.  Thus carboxyalkylating agents, carboxyalkylacylating agents, phosphoric acid esterifying agents, sulphuric acid esterifying agents, aminoalkylating agents and aminoalkylacylating agents may be used to introduce the carboxyalkyl, carboxyacyl, phosphoric acid ester, sulphuric acid ester, aminoalkyl and aminoacyl ion-exchange groups into the parchment molecule, and the electrolyte solution may be an acid, alkali metal or alkaline earth metal electrolyte e.g. hydrochloric acid, sodium or potassium hydroxide, sodium carbonate, sodium chloride and calcium chloride. When phosphoric acid esterifying agents (of which orthophosphoric acid is preferred) or sulphuric acid esterifying agents are used, treatment is desirably effected in the presence of a nitrogenous base anti-tenderizing agent, e.g. urea, pyridine, piperidine, melamine, formamide, guanidine, biuret, acetamide, semi-carbazide, cyanamide or dicyamanide, to prevent hydrolysis of the parchment molecule.  Other phosphorylating agents may be used e.g. alkyl phosphoric acids, polyvinylphosphoric acid, and toluene phosphoric acid. After introduction of the ion-exchange sites into the parchment, it may be re-parchmentized, e.g. using concentrated (i.e. at least 85% by weight) orthophosphoric acid as the parchmentizing reagent. In an alternative method, a cellulose material having ion-exchange sites is subjected to parchmentization, or ion-exchange sites are introduced into a material comprising a cellulose fibre structure and the ion-exchange material then subjected to parchmentization, concentrated ortho-phosphoric acid being the preferred parchmentizing reagent. In a preferred method, cellulose is parchmentized by treatment with phosphoric acid of at least 80% by weight concentration, residual acid carried by the thus-produced parchment diluted, the acid-carrying parchment contacted with a nitrogenous base antitenderizing agent, the mixture of parchment, parchmentizing acid, and nitrogenous base heated to produce phosphoric acid esterification of the parchment, and the product washed with a non-ammonium electrolyte solution.  Several examples are given.ALSO:A parchment ion-exchange reagent comprises an esterified or etherified parchment, having, if the reagent contains phosphorus or sulphur, a maximum of 1% combined nitrogen and having a weight ratio of phosphorus to nitrogen, if the reagent contains phosphorus, or of sulphur to nitrogen, if the reagent contains sulphur, of at least 4 to 1.  Preferred reagents are parchment carboxy-alkylates, parchment carboxyacylates, parchment phosphoric acid esters and sulphuric acid esters, alkali or alkaline earth metal salts of any of these, parchment aminoacylates and parchment aminoalkylates, the reagents having an ion exchange capacity of 0.3-3 milliequivalents per gram, preferably 0.4-2.7 meg. and especially 0.6-2.5 meg.  The parchment treated and the reagent produced may be in sheet form, friable when dry into discrete particulate form, or may be friated into said form, the particles passing a 5 mesh screen (U.S. Standard Series) and preferably being from 10-200 mesh, especially 20-200 mesh. Alternatively, cellulose fibres or flocs, rather than sheets, may be parchmentized and treated to obtain an ion-exchange reagent of very fine particulate form.  Specified reagents are parchment carboxyacetate, carboxymethylate, sodium carboxymethylate, succinate, succinate sodium salt, parchment orthophosphoric acid ester, salts of any of these, parchment aminoethylate and parchment aminoacetate.  As well as the succinate, parchment phthalate, fumarate, oxalate, camphorate, adipate, itaconate, suberate, malate, citrate and mellitate may be made, and in addition to the aminoacetate and aminoethylate parchment carbonate, a -aminopropionate, a -aminobutyrate, a -amino-b -phenylpropionate, a -aminosuccinate, a -e -diaminocaproate, a -amino-b -imidazolepropionate and corresponding b -amino and secondary and tertiary amino products, dimethyl aminoethylate, diethylaminoethylate, and diisopropylaminoethylate may be made.  Parchment may be treated with an esterifying or etherifying agent to introduce chemically attached groups having ion exchange characteristics into the parchment molecule, and the product washed with a solution of a non-ammonium electrolyte to produce a product having a maximum of 1% combined nitrogen by weight, and where applicable, the stated ratio of sulphur to nitrogen or phosphorus to nitrogen.  The parchment may be dried before the washing with electrolyte. Thus carboxyalkylating agents, carboxyalkylacylating agents, phosphoric acid esterifying agents, sulphuric acid esterifying agents, aminoalkylating agents and aminoalkylacylating agents may be used to introduce the carboxyalkyl, carboxyacyl, phosphoric acid ester, sulphuric acid ester, aminoalkyl and aminoacyl ion-exchange groups into the parchment molecule, and the electrolyte solution may be an acid, alkali metal or alkaline earth metal electrolyte e.g. hydrochloric acid, sodium or potassium hydroxide, sodium carbonate, sodium chloride and calcium chloride.  When phosphoric acid esterifying agents (of which orthophosphoric acid is preferred) or sulphuric acid esterifying agents are used, treatment is desirably effected in the presence of a nitrogenous base anti-tenderizing agent, e.g. urea, pyridine, piperidine, melamine, formamide, guanidine, biuret, acetamide, semicarbazide, cyanamide or dicyanamide, to prevent hydrolysis of the parchment molecule.  Other phosphorylating agents may be used e.g. alkyl phosphoric acids, polyvinylphosphoric acid, and toluene phosphoric acid.  After introduction of the ion-exchange sites into the parchment, it may be re-parchmentized, e.g. using concentrated (i.e. at least 8.5% by weight) orthophosphoric acid as the parchmentizing reagent.  In an alternative method, a cellulose material having ion-exchange sites is subjected to parchmentization, or ion-exchange sites are introduced into a material comprising a cellulose fibre structure and the ion-exchange material then subjected to parchmentization, concentrated orthophosphoric acid being the preferred parchmentizing reagent.  In a preferred method, cellulose is parchmentized by treatment with phosphoric acid of at least 80% by weight concentration, residual acid carried by the thus-produced parchment diluted, the acid-carrying parchment contacted with a nitrogenous base antitenderizing agent, the mixture of parchment, parchmentizing acid, and nitrogenous base heated to produce phosphoric acid esterification of the parchment, and the product washed with a non-ammonium electrolyte solution.  Several examples are given.