Showing papers on "Ammonium hydroxide published in 1968"

On the size distribution of water soluble particles in the atmosphere

Abstract: The size distribution of the mass concentration of some water soluble materials was measured by an impactor of three stages and membrane filters. It was found that about the half of the mass of sulfate and ammonium particles is in the range of Aitken nuclei. The size distribution of sulfate particles depends on the relative humidity of the air: more nuclei are in the Aitken size range if the relative humidity is smaller. The size distribution of chloride particles is rather different from that of sulfate and ammonium particles: only a small fraction of the total mass is in the Aitken range. Considering the stoichiometric proportion of the ammonium sulfate, it is an ammonium excess, which is greater in the case of smaller particles. It is not impossible that this ammonium excess is caused by the presence of ammonium hydroxide. It follows from these results that in the Aitken size range there are many sulfate and ammonium particles which may be active cloud nuclei even over the continents. DOI: 10.1111/j.2153-3490.1968.tb00385.x

Identification of (+)-abscisic acid in strawberry leaves.

Abstract: The acidic ether extract of leaves collected in October from dormant strawberry plants outdoors at Invergowrie inhibited coleoptile growth in germinating wheat embryos. On paper chromatograms developed either with isopropanol: ammonium hydroxide: water (10:1:1) or isopropanol: 1% ammonium hydroxide (4:1), the zones possessing inhibitory activity had Rf's 0.6–0.7 and 0.6–1 respectively. Fractions possessing comparable activity were eluted from granular animal charcoal columns by 10% and 20% acetone in water, and, on further purification, eluted only by 10% ethyl acetate in chloroform from columns of celitesilicic acid (2:1). The inhibitor in this fraction was identified as (+)-abscisic acid (abscisin II, dormin) by spectropolarimetry.

Method of modifying electrical resistivity characteristics of dielectric substrates

Abstract: The electrical resistivity characteristics of selected portions of a dielectric substrate, such as barium titanate, may be modified by first forming a relatively porous substrate which may be handled without breaking, as by prefiring the substrate, masking selected portions of the substrate with a material such as a photoresist material which will vaporize during final firing of the substrate, contacting the substrate with a solution of a first reactant, immersing at least a portion of the substrate in a solution of a second reactant which will react with the first reactant to precipitate in situ in a portion of the substrate a compound which is insoluble in the solutions and which is adapted to modify the electrical resistivity characteristics of the substrate, and thereafter firing the substrate at a temperature on the order of 1,400 DEG -1,450 DEG C. to reduce the porosity of the substrate and to incorporate the insoluble compound into the lattice of selected portions of the substrate. Where it is desired to dope selected portions of an undoped substrate to the desired thickness and form thick-film positive temperature coefficient (PTC) thermistors, the starting material may be an undoped barium titanate, for example, the solution of the first reactant may be an aqueous solution of a compound such as ammonium hydroxide, and the solution of the second reactant may be an aqueous solution of a compound such as lanthanum acetate which reacts with the ammonium hydroxide to precipitate lanthanum hydroxide in situ and thereby dope selected portions of the substrate. Where it is desired to produce areas of high-electrical resistivity in selected portions of the substrate, the starting material is a doped barium titanate, for example, the solution of the first reactant may be an aqueous solution of a compound such as ammonium hydroxide, and the solution of the second reactant may be an aqueous solution of a ferric compound such as ferric chloride which reacts with the ammonium hydroxide to precipitate in situ ferric hydroxide which, when fired, produces a high-resistivity area.

Silica aquasols and powders

Abstract: SILICA AQUASOLS ARE MADE BY PROVIDING A HEEL OF A SILICA SOL CONTAINING AQUEOUS AMMONIUM HYDROXIDE IN A REACTION VESSEL. FINELY DIVIDED SILICON METAL IS INTRODUCED INTO THE HEEL AND THE METAL AND WATER REACT TO FORM SILICA. THE CONCENTRATION AND SURFACE AREA OF THE SILICA IN THE HEEL AND THE PRODUCTION RATE OF SILICA IN THE REACTION MIXTURE ARE SUCH THAT THE SILICA FORMED POLYERIZES ON THE HEEL PARTICLES TO PROVIDED NOVEL, SPHERICAL SILICA PARTICLES HAVING A SURFACE AREA AVERAGE DIAMETER BETWEEN 150 AND 500 MU.

Process for producing isothiocyanates

Abstract: A NOVEL PROCESS IS DESCRIBED FOR CONVERTING A PRIMARY AMINE TO THE CORRESPONDING ISOTHIOCYANATE VIA THE INTERMEDIATE AMMONIUM DITHIOCARBAMATE. THE LATTER IS PREPARED BY REACTING THE AMINE WITH CARBON DISULFIDE IN THE PRESENCE OF AMMONIUM HYDROXIDE IN ACCORDANCE WITH CONVENTIONAL METHODS AND THE DITHIOCARBAMATE IS REACTED WITH NITOUS ACID, ADVANTAGEOUSLY FORMED IN SITU, AT A PH NOT LESS THAN 5.0 TO OBTAIN THE DESIRED ISOTHIOCYANATE. ADVANTAGES OF THE NOVEL PROCESS ARE HIGH YIELD, USE OF LOW COST RECTANTS, AND EASE OF OPERATIN9

Alkaline treatment of hops and resulting product

Abstract: A HOPS PRODUCT, INCLUDING THE LUPULIN GLANDS OF HOPS HAVING IMPROVED EFFECTIVENESS IS OBTAINED BY SUBJECTING HOPS MATERIAL, SUCH AS BALED DRIED HOPS, LOOSE, FIELD DRIED HOPS OR THE SEPARATED LUPULIN GLANDS OF HOPS, TO CONTACT WITH A GASEOUS OR VAPORIZED ALKALINE-ACTING TREATING AGENT, SUCH AS ANHYDROUS AMMONIA, AMMONIUM HYDROXIDE AND/ OR AQUEOUS SODIUM HYDROXIDE, SUBSEQUENTLY TREATING THE HOPS MATERIAL WITH A GASEOUS OR VAPORIZED AGENT, SUCH AS HYDROGEN CHLORIDE, HYDROCHLORIC ACID OR METHYL CHLORIDE, AND SUBJECTING THE RESULTING TREATED HOPS MATERIAL TO A REDUCED PRESSURE TO EFFECT REMOVAL OF THE READILY VOLTALIZABLE MATERIALS THEREFROM.

Production of surface coatings

Abstract: A coating composition comprises a dispersion of a film-forming resin in an aqueous medium including an aldehyde or a ketone and a component which contains solubilizing groups and has been made water-soluble or water-dispersible by treatment with a base, the base being liberated as free base during formation of a water-insoluble coating, the aldehyde or ketone being capable of reacting with free base to form a non-ionic compound, and the resin being incapable of modification by aldehyde or ketone under the conditions existing in the coating medium. The component made water-soluble or water-dispersible may be the film-forming resin or a dispersing or emulsifying resin for such resin. The base may consist of ammonia, primary, secondary, tertiary amines, hydroxylamine or its amine derivatives and compounds capable of reacting with such bases are formaldehyde, paraformaldehyde, acetaldehyde, or polymers thereof, glyoxal, chloral, acetophenone. The resin deposited e.g. a phenolic resin may react with the non-ionic product e.g. hexamethylene tetramine to effect cross-linking of the resin, and additional hexamethylene tetramine may be dissolved in the bath to maintain an increased concentration sufficient to complete the cross-linking. The film-forming resin may be natural or synthetic e.g. an ammonium salt of a polycarboxylic resin. In the examples, steel panels are coated by electrodeposition using a bath containing an aqueous solution of amine neutralized maleinized copolymer resin oil and (1) paraformaldehyde at an initial pH of 8.8 rising to 8.95, (2) formaldehyde at pH 9.0 rising to 9.05; steel panels are coated and form the anode in a bath of paint comprising a water dispersion of (4) a modified carboxylated oil, iron oxide pigment, talc, hexamethylene tetramine, formaldehyde at pH 7.0, (5) the resin of (1), carbon black, hexamethylene tetramine, paraformaldehyde at pH 9.0; in (6) a solution of a methacrylic acid - ethyl acrylate - 2 ethyl hexyl acrylate-styrene copolymer rendered soluble by the addition of ammonium hydroxide and containing formaldehyde is applied by spraying or electrodeposition at pH 9.7 to zinc; (7) steel panels are coated by electrodeposition using a bath comprising a phenolic-alkyd resin dispersion containing glyoxal; (8) a paint comprising a copolymer as in (6), zinc-coated rutile titanium dioxide, hexamethoxymethyl-melamine, formaldehyde is sprayed at pH 9.0 on to glass and baked; (9) mild steel panels are passed in succession through an electrodeposition bath having the composition described in (5) but omitting paraformaldehyde and replenished by the paint containing formaldehyde; (10) steel panels are coated in an electrodeposition bath comprising the composition described in (1), solid paraformaldehyde being present in the cathode compartment.ALSO:Coatings are produced by the application to the surface to be coated of an aqueous coating medium containing a film-forming resin capable of forming a coherent, paint-like or lacquer coating, such medium including a component which contains solubilizing groups and has been made water-soluble or water-dispersible by treatment with a base which is liberated as free base during formation of a water-insoluble coating of the resin on the surfaces, and an aldehyde or a ketone, or a compound containing an aldehyde group or a ketone group, capable of reacting with free base to form a non-ionic compound, the resin being incapable of modification by aldehyde or ketone under the conditions existing in the coating medium. The component made water-soluble or water dispersible may be the film forming resin or a dispersing or emulsifying resin for such resin. The surface may be of non-absorbent or absorbent materials such as paper, fabrics, non-woven fabrics. The coating can be produced by electro-deposition, and the effect of including an aldehyde or ketone is that pH value in the electro-deposition bath remains constant during coating and may be brought to any desired value. The base may consist of ammonia, primary, secondary, tertiary amines, hydroxylamine or its amine derivatives and compounds capable of reacting with such bases are formaldehyde, paraformaldehyde, acetaldehyde, or polymers thereof, glyoxal, chloral, acetophenone. The reactive substance e.g. formaldehyde may be added in solid, gaseous or aqueous form to the electro-deposition bath so as to be distributed throughout, or added to any liquid used to replenish the bath, or at any stage to reduce the pH as necessary, or to the cathode compartment, or the contents of the bath or cathode compartment may be circulated by pumping through say a tower in which a supply of formaldehyde is maintained. The resin deposited e.g. a phenolic resin may react with the non-ionic product e.g. hexamethylene tetramine to effect cross-linking of the resin, and additional hexamethylene tetramine may be dissolved in the bath to maintain an increased concentration sufficient to complete the cross-linking. The film-forming resin may be natural or synthetic e.g. an ammonium salt of a polycarboxylic resin. In the Examples, steel panels are coated by electro-deposition using a bath containing an aqueous solution of amine neutralised maleinized copolymer resin oil and (1) paraformaldehyde at an initial pH of 8.8 rising to 8.95, (2) formaldehyde at pH 9.0 rising to 9.05; steel panels are coated and form the anode in a bath of paint comprising a water dispersion of (4) a modified carboxylated oil, iron oxide pigment, talc, hexamethylene tetramine, formaldehyde at pH 7.0, (5) the resin of (1), carbon black, hexamethylene tetramine, paraformaldehyde at pH 9.0; in (6) a solution of a methacrylic acid-ethyl acrylate-2 ethyl hexyl acrylate-styrene copolymer rendered soluble by the addition of ammonium hydroxide and containing formaldehyde is applied by electro-deposition at pH 9.7 to zinc; (7) steel panels are coated by electro-deposition using a bath comprising a phenolic-alkyd resin dispersion containing glyoxal; (9) mild steel panels are passed in succession through an electro-deposition bath having the composition described in (5) but omitting paraformaldehyde and replenished by the paint containing formaldehyde; (10) steel panels are coated in an electro-deposition bath comprising the composition described in (1), solid paraformaldehyde being present in the cathode compartment.ALSO:Coatings are produced by the application to the surface to be coated of an aqueous coating medium containing a film-forming resin capable of forming a coherent, paint-like or lacquer coating, such medium including a component which contains solubilising groups and has been made water-soluble or water-dispersible by treatment with a base which is liberated as free base during formation of a water-insoluble coating of the resin on the surfaces, and an aldehyde or a ketone, or a compound containing an aldehyde group or a ketone group, capable of reacting with free base to form a non-ionic compound, the resin being incapable of modification by aldehyde or ketone under the conditions existing in the coating medium. The component made water-soluble or water dispersible may be the film forming resin or a dispersing or emulsifying resin for such resin. The surface may be of non-absorbent or absorbent materials such as paper, fabrics, non-woven fabrics. The coating can be produced by electro-deposition, and the effect of including an aldehyde or ketone is that pH value in the electrodeposition bath remains constant during coating and may be brought to any desired value. The base may consist of ammonia, primary, secondary, tertiary amines, hydroxylamine or its amine derivatives and compounds capable of reacting with such bases are formaldehyde, paraformaldehyde, acetaldehyde, or polymers thereof, glyoxal, chloral, acetophenone. The reactive substance, e.g. formaldehyde may be added in solid, gaseous or aqueous form to the electrodeposition bath so as to be distributed throughout, or added to any liquid used to replenish the bath, or at any stage to reduce the pH as necessary, or to the cathode compartment, or the contents of the bath or cathode compartment may be circulated by pumping through say a tower in which a supply of formaldehyde is maintained. The resin deposited, e.g. a phenolic resin may react with the non-ionic product, e.g. hexamethylene tetramine to effect cross-linking of the resin, and additional hexamethylene tetramine may be dissolved in the bath to maintain an increased concentration sufficient to complete the cross-linking. The film-forming resin may be natural or synthetic, e.g. an ammonium salt of a polycarboxylic resin. In the Examples, steel panels are coated by electrodeposition using a bath containing an aqueous solution of amine neutralised maleinised copolymer resin oil and (1) paraformaldehyde at an initial pH of 8.8 rising to 8.95, (2) formaldehyde at pH 9.0 rising to 9.05; steel panels are coated and form the anode in a bath of paint comprising a water dispersion of (4) a modified carboxylated oil, iron oxide pigment, talc, hexamethylene tetramine, formaldehyde at pH 7.0, (5) the resin of (1), carbon black, hexamethylene tetramine, paraformaldehyde at pH 9.0, in (6) a solution of a methacrylic acid-ethyl acrylate-2 ethyl hexyl acrylate-styrene copolymer rendered soluble by the addition of ammonium hydroxide and containing formaldehyde is applied by spraying or electrodeposition at pH 9.7 to zinc; (7) steel panels are coated by electrodeposition using a bath comprising a phenolic-alkyd resin dispersion containing glyoxal; (8) a paint comprising a copolymer as in (6), zinc-coated rutile titanium dioxide, hexamethoxy-methyl-melamine, formaldehyde is sprayed at pH 9.0 on to glass and baked; (9) mild steel panels are passed in succession through an electrodeposition bath having the composition described in (5) but omitting paraformaldehyde and

Method of producing spheroidal agglomerates

Abstract: A METHOD OF FORMING SHEROIDAL AGGLOMERATES OF PARTICLES IN WHICH OLEIC ACID IS MIXED WITH A POWDERED CERAMIC MATEIAL, ADDING TO THIS MIXTURE AMMONIUM HYDROXIDE, AND SUBSEQUENTLY AGITATING.

Improvements in the preparation of organophosphonic acids and their salts

Abstract: Organophosphonic acids including those of the formulae CH3COPO(OH)2 CH3CO[CH3CO(PO3)2H4] and are obtained by reacting acetic acid with a phosphorus trihalide PX3, where X represents halogen, e.g. phosphorus trichloride, and employing at least 3.5 molar proportions of acetic acid per mole of phosphorus trihalide. The process may be carried out by heating the phosphorus trihalide with acetic acid, which may be glacial acetic acid or may contain a minor proportion of water (less than 10% by weight) or acetic anhydride, for at least an hour at a temperature above 80 DEG C. Under such conditions the product separates into two layers with substantially all the phosphorus being contained in the lower layer. 1-Hydroxyethylidenediphosphonic acid (III) may be obtained by contacting the reaction mixture with water or steam preferably above 100 DEG C., e.g. by steam stripping, heating to 110-120 DEG C. to remove volatile impurities and recrystallizing, and salts of this acid may be obtained by contacting the reaction mixture with an aqueous suspension or solution of a base, e.g. sodium hydroxide, rubidium carbonate or ammonium hydroxide or with silver nitrate, calcium nitrate or cobaltous chloride. Acetoxyethylidene-diphosphonic acid (II) may be obtained by dissolving the lower layer of the reaction mixture in a hot non-aqueous solvent (e.g. glacial acetic acid) and allowing it to crystallize. The invention also comprises the latter compound, which is believed to have the structure per se and it may also be obtained by reacting acetic acid with a phosphorus trihalide at a temperature below 50 DEG C. and recrystallizing the precipitate so formed from glacial acetic acid.

Process for treating electrolytically chromated metal surfaces

Abstract: A process for treatment of an electrolytically chromated metal before the chromate coating thereon is allowed to dry comprises rinsing with water; immersing in an aqueous solution containing a total of from 1 to 100 gms/1 of at least one of ammonium hydroxide, alkali metal hydroxides, alkaline earth metal hydroxides, and alkali metal and ammonium acetates, borates, carbonates, bicarbonates, chromates, dichromates, formates, oxalates, phosphates, pyrophosphates, hypophosphates, phosphites, hypophosphites and silicates; further rinsing with water and thereafter drying of the chromated metal. The temperature of the aqueous solution is preferably 30 DEG to 70 DEG C., and the immersion time therein is preferably 1 to 30 secs. The chromated metal may be cathodically treated in said solution, preferably using a current density of less than 10 A/dm2. The treatment may be applied to chromate coatings formed on iron, steel, aluminium, zinc, tin, nickel, chromium or an alloy thereof.

Process for the isolation of tetracycline antibiotics from impure solutions thereof

Abstract: 1,132,124. Tungstate complexes of tetracyclines. KRKA TOVARNA ZDRAVIL. 28 April, 1966, No. 18643/66. Heading C2A. Tetracyclines are isolated from fermentation broths freed from mycelium, or other tetracycline containing aqueous solutions, by precipitating the antibiotic as a tungstate complex by treatment at pH 0A5 to 7A0, with tungstic acid or a water-soluble salt thereof in a weight ratio to the antibiotic of from 0A5:1 to 4A0:1, and then dissolving the precipitate by addition of sufficient sodium hydroxide solution to give a final pH of 8A5 to 10A0 and recovering the antibiotic from this solution. The antibiotic is preferably recovered by either (i) addition of HCl to the alkaline solution to bring the pH to about 7A5, and then adding solid ammonium chloride in a ratio by weight with regard to antibiotic of 1:1 to 3:1, treating this solution with a solution of a magnesium or calcium salt, preferably the chloride, to give a ratio of 1:1 to 1: 4 to the antibiotic, and bringing the pH to 8A0 to 8A2, when the Ca or Mg salt of the tetracycline is precipitated; or (ii) by passage of the alkaline solution first through a column of cation-exchange resin, which takes up the antibiotic, eluting the column with ammonium hydroxide, and then passing the eluate through an anion-exchange resin column, when the antibiotic crystallizes from the solution obtained, after suitable concentration. The tungstic acid or tungstate may be recovered from appropriate stages in the purification by addition of cone. hydrochloric acid, which precipitates the tungstic acid; the latter may be re-employed in the inventive process. Tungstic acid salts employed are ammonium metatungstate and paratungstate, potassium orthotungstate, metatungstate and paratungstate, sodium orthotungstate and paratungstate, and cadmium borotungstate; phosphotungstic acid may also be used.

Process for the production of aminoguanidine bicarbonate

Abstract: Production of aminoguanidine bicarbonate by reacting finely divided solid calcium cyanamide with hydrazine, in the form of mono or dihydrazine sulfate or hydrazine hydrate and sulfuric acid in admixture, in neutral to alkaline aqueous medium, e.g. at pH 7 to about 9.5 and about 15 DEG -90 DEG C, using sulfuric acid for pH adjustment to form aminoguanidine, cooling the reaction mixture, e.g. to about 60 DEG -40 DEG C, to precipitate the resultant calcium sulfate sludge, and treating the sludge-free resultant reaction mixture, e.g. at 25 DEG -50 DEG C, with a bicarbonate precipitating agent, e.g. alkali metal or ammonium bicarbonate or carbon dioxide and alkali metal or ammonium hydroxide, to precipitate the aminoguanidine bicarbonate therefrom; OPTIONALLY AVOIDING IRON CONTAMINATION OF THE DESIRED PRODUCT BY EITHER ADJUSTING TO ACID PH, e.g. pH 3-4, the reaction mixture prior to bicarbonate agent treatment to maintain such iron in soluble form, e.g. when Fe content low, or adjusting to about pH 7.5-8.5 the reaction mixture prior to bicarbonate agent treatment followed by air introduction, e.g. at 60 DEG -45 DEG C, to remove the iron content, e.g. when Fe content high-up to about 5 percent, as ferric hydroxide precipitate, the latter alternative being optionally carried out prior to calcium sulfate sludge precipitation (i.e. removal) to effect joint precipitation of such ferric hydroxide and sludge prior to bicarbonate treatment.

Improvements in or relating to the processing of clay

Abstract: Clay, e.g. kaolin or china clay, is treated to remove titanium mineral impurities by mixing with a suspension of the clay in water a flotation assistant consisting of a water-soluble salt of an alkaline earth (including magnesium) metal or a metal having a sp. gr. greater than 4, an alkali to raise the pH to about 9, a collector for impurities, a frothing agent and subjecting the suspension to a froth flotation process. The suspension may first be deflocculated by adding a deflocculating agent, e.g. sodium silicate, and after adding all the reagents the suspension may be conditioned by agitation. Before flotation is commenced the suspension may be diluted with water to a solids content of 15-20% w./v. The collector for impurities may be oleic acid, the frothing agent pine oil and the alkali ammonium hydroxide. The compounds specified as flotation assistants are water-soluble salts of Ca, Sr, Cu11, Fc11, Pb11, Mn11, and Zn and especially lead acetate, lead nitrate and barium chloride.ALSO:Clay e.g. kaolin or china clay, is treated to remove titanium mineral impurities by mixing with a suspension of the clay in water a flotation assistant consisting of a water soluble salt of an alkaline earth (including magnesium) metal or a metal having a sp.gr. greater than 4, an alkali to raise the pH to about 9, a collector for impurities, a frothing agent and subjecting the suspension to a froth flotation process. The suspension may first be deflocculated by adding a deflocculating agent e.g. sodium silicate, and after adding all the reagents the suspension may be conditioned by agitation. Before flotation is commenced the suspension may be diluted with water to a solids content of 15-20% w/v. The collector for impurities may be oleic acid, the frothing agent pine oil and the alkali ammonium hydroxide. The compounds specified as flotation assistants are water soluble salts of Ca, Sr, CuII, FcII, PbII, MnII, and Zn and especially lead acetate, lead nitrate and barium chloride.

Improved process for preparing linear olefins

Abstract: Linear alpha-olefins having number average M.W.'s of 70-300 are prepared by polymerizing ethylene in the presence of a catalyst comprising the reaction product of a compound of formula TiX4, TiX3OR1, or TiX3OOC.R1 (where X is Cl or Br, and R1 is alkyl, allyl, aralkyl or cycloalkyl), and an aluminium alkyl compound such that the ultimate formula of the aluminium alkyl compound is AlRnX3- n (where X is Cl, Br or I, R is alkyl, aralkyl or cycloalkyl, and n is less than 2); in the presence of a diluent, at a temperature below 75% C., at an ethylene pressure above 50 p.s.i.a., the mole ratio of ethylene to the olefin reaction product being above 0.8, and a base being added to the reaction mixture in order to terminate the reaction. Suitable diluents include benzene, chlorotoluene, tetrahydronaphthalene and dichloromethane, others being mentioned. The catalyst may be modified by the presence of a C1- 15 alcohol. The base used to terminate the reaction may be an alkali metal or alkaline earth metal hydroxide or carbonate, ammonium hydroxide, a quaternary ammonium base, or a Lewis base, such as ammonia, an amine, a cyclic nitrogen base, or an ether. Water, an alcohol, or a glycol may also be added to kill the catalyst, either before, after, or simultaneously with, the base.ALSO:Linear alpha-olefins having number average M.W.'s of 70-300 are prepared by polymerizing ethylene in the presence of a catalyst comprising the reaction product of a compound of formula TiX4, TiX3OR1, or TiX3OOC.R1 (where is Cl or Br, and R1 is alkyl, allyl, aralkyl or cycloalkyl), and an aluminium alkyl compound such that the ultimate formula of the aluminium alkyl compound is AlRnX3-n (where X is Cl, Br or I, R is alkyl, aralkyl or cycloalkyl, and n is less than 2); in the presence of a diluent, at a temperature below 75 DEG C., at an ethylene pressure above 50 p.s.i.a., the mole ratio of ethylene to the olefin reaction product being above 0.8, and a base being added to the reaction mixture in order to terminate the reaction. Suitable diluents include benzene, chlorotoluene, tetrahydronaphthalene and dichloromethane, others being mentioned. The catalyst may be modified by the presence of a C1-15 alcohol. The base used to terminate the reaction may be an alkali metal or alkaline earth metal hydroxide or carbonate, ammonium hydroxide, a quaternary ammonium base, or a Lewis base, such as ammonia, an amine, a cyclic nitrogen base, or an ether. Water, an alcohol, or a glycol may also be added to kill the catalyst, either before, after, or simultaneously with the base.