US2085750A - Electrodeposition of cadmium - Google Patents

Electrodeposition of cadmium Download PDF

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US2085750A
US2085750A US45404A US4540435A US2085750A US 2085750 A US2085750 A US 2085750A US 45404 A US45404 A US 45404A US 4540435 A US4540435 A US 4540435A US 2085750 A US2085750 A US 2085750A
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cyanide
cadmium
product
reaction
addition agent
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Jr John A Henricks
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EIDP Inc
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EI Du Pont de Nemours and Co
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/26—Electroplating: Baths therefor from solutions of cadmium
    • C25D3/28—Electroplating: Baths therefor from solutions of cadmium from cyanide baths

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  • This invention relates to the electrodeposition of cadmium from cyanide-cadmium baths, and
  • - is particularly directed to cyanide-cadmium plating compositions, plating baths, and plating proc- 5 esses which employ, as an addition agent, anisoamketaldoresin whereby a bright, smooth, uniform cadmium deposit is obtained.
  • orlO ganic addition agents such as sulflte cellulose waste, dextrin, starch, alkylated naphthalene suifonic acids, wool, caffeine, shellac, casein, licorice, glucose, alkali reaction products of heterocyclic aldehydes, furfural, gum arabic, and gelatine.
  • ketaldones are particularly suitable for my purpose.
  • My preferred starting materials are, generally speaking, aliphatic and carbocyclic ketaldone's, that is aldehydes and ketones, but, as will become apparent hereinafter, the best results are obtained by the use of certain aliphatic and carbocyclic aldehydes and ketones.
  • the carbonyl group as'it appears in acids
  • ketaldonyl group designates a carbonyl group in which a third carbon valence is joined to carbon and in which the remaining valence is satisfied by carbon or by hydrogen.
  • the "ketaldonyl group" as used herein is of the type wherein R is a hydrocarbon radical and wherein R. is hydrogen, in the case of an aldehyde, or R.
  • ketaldones is a hydrocarbon radical, in the case of a ketone. It will also be understood that the ketones and aldehydes themselves are referred to herein as ketaldones in accordance with this terminology.
  • Thestarting materials which I employ are, broadly, ketaldones. While I may use-aldoses', ketoses, heterocyclic aldehydes and ketones or any other such ketaldones, I prefer to use aliphatic 6 than two hydroxyl groups and preferably should contain at least two carbon atoms. More specifically, I prefer to employ ketaldones which contain only carbon, hydrogen, and oxygen, which contain at least two carbon atoms, and in which the hyl drogen-oxygen ratio is greater than that of water.
  • the starting materials, the ketaldones are reacted with ammonia or an amine, in alkaline solution, to pro- 15 quiz an amo-reactionproduct.
  • amo is used to designate both ammonia and an amine.
  • the amo-reaction products of the ketaldones are very similar in their physical and 20 chemical characteristics. They all contain nitrogen, and all are, apparently, complex mixtures. I have, accordingly, designated these reaction products amketaldoresins. The nature of the products and the nature of the reaction will be discussed in more detail hereinafter.
  • amketaldoresins may subsequently be modified by hydrogenation, oxidation, halogenation, or other such treatment which does not destroy the essential character of the product, to yield 30 nitrogen-containing derivatives which are effective as addition agents.
  • These derivatives are very similar to the amketaldoresins, ordinarilydifl'ering slightly as to color, solubility, and degree of effectiveness as addition agents.
  • amketaldoresins and these derivatives are herein designated isoamketaldoresins".
  • the isoamketaldoresins are the amine or ammonia reaction products of aldehydes or ketones, or nitrogen-containing derivatives of such products 40 produced by hydrogenation, oxidation, and the like.
  • the isoamketaldoresins are addition agents for cyanide-cadmium plating and are amketaldoresin derivatives. which contain 4 nitrogen and in which the carbon skeleton of 50 garding the members of the illustrated aldacet the amketaldoresin is unmodified.
  • a preferred group of ketaldones, the aldacet are illustrated in the upper right-hand corner of the drawing. More will be said hereinafter reequilibrium. As is shown in the drawing, the
  • aldacets like the ketaldones generally, are reactedwith ammonia, an amine, or cyanide to produce an amketaldoresin.
  • amketaldo- 55 resins produced from the aldacets are designated herein, the amaldacets.
  • amaldacets may be reacted, as were the amketaldoresins generally, with hydrogen, oxygen, halogen, or the like to produce nitrogen- 0- containing derivatives.
  • These derivatives, jointly with the amaldacets, are, of course, isoamketaldoresins derived from the aldacets, and this group,
  • amaldacets and their nitrogen-containing derivatives is termed the 65 isoamalclacets.
  • ketaldones which I employ as starting materials are reacted in weak alkaline solution with an amo to produce an amo-reaction product which constitutes an addition agent of my inven- 70 tion.
  • amo-reaction product which constitutes an addition agent of my inven- 70 tion.
  • cyanide is considered substantially equivalent to reacting the ketaldones with amoes in alkaline solution.
  • the isoamketaldoresins are preferably derived from the aliphatic ketaldones termed the a dacets.
  • the derivatives ofthealdacets are typical of the isoamketaldoresins, and their preparation will be described below in some detail as illustrative of the isoamketaldoresins generally.
  • the aldacets comprise the aliphatic aldehydes: acetaldehyde, aldol, crotonaldehyde, and paraldol.
  • acetaldehyde acetaldehyde
  • aldol aldol
  • crotonaldehyde a crotonaldehyde
  • paraldol aliphatic aldehydes
  • the aldacets appear to exist in equilibrium, any one of the aldacets leading to the production of all at a rate of conversion apparently depending upon the specific aldacet first present.
  • the aldacet equilibrium is illustrated in the upper, right corner of the drawing.
  • the aldol may lose one molecule of water and become crotonaldehyde, thus:
  • the aldol may condense to form paraldol, thus:
  • the aldol may go to paraldol or to crotonaldehyde.
  • the aldol might also go back to acetaldehyde, but only to a small extent.
  • the paraldol may go back to aldol, or it may lose water and go to crotonaldehyde, though this latter conversion probably takes place to a very small degree.
  • the crotonaldehyde may form from acetaldehyde, aldol, or paraldol, and, by gaining water, may revert to any of them, though it is likely that it would move largely by way of aldol.
  • the aldacets As is seen in the drawing, then, we may consider the aldacets as being in equilibrium. This equilibrium will, according to my belief, be substantially the same regardless of which of the four substances are initially added to the cyanide solution, though, as will hereinafter be noted, the aldacets are not entirely equivalent and it is possible that some of the aldacets in dilute alkaline solution form this aldacet equilibrium rather slowly or move more rapidly in certain directions than in others.
  • Aldol, acetaldehyde, crotonaldehyde, and paraldol are the only commercially available aldacets at the present time. For practical reasons,
  • aldacets are aliphatic aldehydes from the group consisting of acetaldehyde and its condensation of equilibrium products in alkaline and alkali metal cyanide solutions.
  • the aldacets are reversible equilibrium-condensation products of acetaldehyde in alkaline solution and particularly in alkaline solutions such-as those of the following Examples I and X. i
  • the aldacets are not entirely equivalent for my purposes but are substantially so.
  • Crotonaldehyde seems to lead to slightly lower yields. This may be attributable to the fact that crotonaldehyde is but slowly converted to the necessary form, or to some other now unknown cause.
  • amketaldoresins prucked from the a dacets it is first noted that the specific amke a doresins produced by the reaction of the aldacets with amoes or cyanide in alkaline solutions are termed amaldacets.
  • amaldacets are almost indistinguishable from one another in physical and chemical properties though, as will be noted hereinafter, they differ slightly from one another as to their efficiency as addition agents for cyanide-cadmium plating.
  • reaction is used to express whatever occurs when the ketaldones, or specifically the aldacets, are treated in alkaline solution with cyanide or with an amo.
  • reaction is used to distinguish from "com? nsation" as used above with reference to the aldacet equilibrium though, in fact, the reaction probably includes both polymerizations and condensations.
  • amaldacets as well as the amketaldoresins contain nitrogen as determined by the Kjeldahl method.
  • thenitrogen is present in about the ratio of one nitrogen atom to each two molecules of aldol (four of acetaldehyde, one of paraldol, etc.). I have been unable to determine how the nitrogen is located in the amaldacet molecules, and insufficient evidence is available to warrant any assumptions.
  • amaldacets are not simple compounds, but are complex mixtures, is evidenced by the fact that portions are water-soluble, other portions chloroform-soluble, etc. It seems probable that the amaldacets are the result of many intricate polymerizations, condensations. and reactions. There may be some condensation products which are not combined with nitrogen, but the fact that a molecular proportion,or an excess. of an amo or of an alkali metal cyanide, to aldehyde give the best results, leads to the belief that the amount of such uncombined products is relatively small. The reaction which leads to the amaldacets takes place, I believe, between ammonia, an amine, or possibly CN- and one or more of the aldacets.
  • This reaction is illus-.- trated in the drawing by dashed lines;-
  • the aldacet. or aldacets, which react with the nitrogen compound may go first to some other and unknown form and then react; I conceive of the reaction as withdrawing one, or more, of the aldacets from the equilibrium with the result that the remaining aldacets move towards the removed materials to restore the equilibrium, and are so all finally utilized.
  • Example II A similar amaldacet was produced by reactin equimolecular proportions of aldol and monoethanolamine. A product exceedingly similar to the one of Example I was produced.
  • Example III One-half mole of monoethanolamine and one mole of aldol were reacted at temperatures be- This amaldacet protween 30 and 40 C. The product was not as soluble as the product of Example II, and it was not as satisfactory an addition agent for use in cyanide-cadmium'plating.
  • Example I V Equimolecular proportions of aldol and diethanolamine were reacted at room temperatures. A product very similar to those of the above examples was produced, the product of this example, however, being slightly less soluble than the product of Examples I and II.
  • Example V Example VI Aldol was treated with ammonia gas by bubbling the gas through the aldol until no further reaction was noted.
  • the reaction product was rather difilcultly soluble, and was only a moderately efiicient addition agent for cya de-cadmium plating baths.
  • Example VIII Qrotonaldehyde and ammonia gas were reacted at about twenty-five degrees centigrade. vThe product was very similar to that of the preceding example. After a few days the product of this example solidified to a brittle, red resin.
  • Example IX Acetaldehyde was treated with an excess of gaseous ammonia. An amaldacet similar to that of the preceding example was obtained.
  • ammonia ammonium hydroxide
  • ammonium hydroxide ammonium hydroxide
  • other amoes may be used.
  • I may. for instance, prepare the amaldacets by treating the aldacets with amines such as the glucamines, for instance, glucamine and methyl glucamine, or aliphatic amines, for instance, methyl ethylamine, methylamine, and ethylamine.
  • amines such as the glucamines, for instance, glucamine and methyl glucamine, or aliphatic amines, for instance, methyl ethylamine, methylamine, and ethylamine.
  • amaldacets may be prepared by conducting the reactions of the above examples at rather widely varied temperatures, I prefer that Y the reaction be performed at temperatures between about thirty and fifty degrees centigrade. If much lower temperatures be maintained, the reaction products will tend to contain insoluble or relatively inactive constituents. Similarly, the reaction temperatures should not be permitted to r se too high, because, when the reaction proceeds at high temperatures, the reaction product may contain insoluble constituents and .may have none too great an efliciency as an addition agent.
  • amaldacets by the direct reaction of ammonia or amines with the aldacets, they may be prepared by reacting the aldacets with alkali cyanides.
  • the cyanides are known to hydrolize to produce ammonia and fonnates according to the following illustrative reaction:
  • reaction products of aldacets with alkali metalcyanides are somewhat more desirable than the reaction products of the aldacets with amoes.
  • Example X Five parts, by weight, of technical aldol were added to a solution containing three parts, by
  • the solution after being allowed to cool, was made neutral to litmus with a dilute solution of sulfuric acid.
  • the acid solution consisted of one part by volume of water toone part by volume of concentrated sulfuric acid. There was then added an excess of ten per cent over the volume of dilute acid required to neutralize the solution. Sodium sulfate was precipitated, and the excess acid used depressed its solubility. The temperature was not allowed to go above 50 C. during this neutralization treatment. Hydrocyanic acid gas was evolved during the treatment and means were provided for disposing of it.
  • the acid treated solution was allowed to stand for several hours and a dark red fraction rose to the top. This top layer was removed and centrifuged.
  • the separated top layer which constitutes a preferred product of my invention is absorbcous liquid, dark red in color, and it has a specific gravity of about 1.20. At temperatures as low as --17 C. it remains liquid, but at the temperature produced with a freezing mixture of solid carbon dioxide and-acetone (below 80 C.) a brittle solid, formed.
  • My product is substantially insoluble in such solventsas ether, benzene, and petroleum ether. It is, however, completely soluble in alcohol and acetone.
  • the products of this example are entirely soluble 'in cyanide plating baths up to about three grams per liter.
  • One characteristic of both the final product and the unseparated reaction mixture is that when used in cyanide cadmium plating baths they exhibit the property of causing a bright deposit of cadmium. Thischaracteristic serves admirably for the identifi cation of my novel products.
  • amaldacets of this example are not chemical compounds, but are mixtures as is evidenced by the fact that portions of the products are water-soluble and a smaller portion of the products is chloroform-soluble.
  • the amaldacets of this example are not chemical compounds, but are mixtures as is evidenced by the fact that portions of the products are water-soluble and a smaller portion of the products is chloroform-soluble.
  • water soluble portion exhibits the property of promoting the formation of a bright finish on recessed parts of an article.
  • the water insoluble portion seems to exercise its major influence on the brightness of the less recessed parts .of the article.
  • the chloroform soluble fraction is very active as an addition agent, but when used alone it is not satisfactory as it causes streaks and stains on the plated article.
  • the temperature of the reaction is relatively important as the yield of the product and its activity as an addition agent seem. to be greatly influenced thereby. The best results seem to be obtained with temperatures between about 45 and 50 C. as used in this example. If lower temperatures are used, there is a decrease in the activity of the product as an addition agent.
  • the yield of active material is smaller. 'At about 75 C., for instance, about one-half of the product is an insoluble resin without much value as an addition agent. Generally, I may use temperatures from about 30 C. to about 75 C., though more specifically I prefer to keep the reaction temperature between about 45 and 50 C.
  • reaction product may be heated to rather high temperatures without substantial damage resulting.
  • sulfuric acid is employed for removing excess sodium cyanide by converting it to sodium sulfate which then acts to salt out the addition agent.
  • acids can be used which lead to a similar result, and moreover, still othermeans for removing the, excess sodium cyanide will readily occur to those working in the art.
  • aldol is also advantageously employed by reason of its being less volatile than acetaldehyde and more easily handled than paraldol which is a solid.
  • the reaction mixture is preferably concentrated by treatment with dilute sulfuric acid, as described in Example X.
  • the product is substantially identical with the concentrated product of Example X described in detail above.
  • Example XI' a smaller ratio of cyanide to aldehyde was used than in Example X. This seems to lower the yield of active material somewhat. Generally, the best. results are obtained when the aldehyde and cyanide are used in substantially molecular proportions, but a latitude is permissible.
  • the product will be less active, while if an excess of alkali metal cyanide be used, no particular damage results.
  • the product is concentrated by neutralizing with dilute sulfuric acid,v the excess of cyanide, over that required tofo'rm'" the reaction product, is converted to alkali sulfate and hydrocyanic gas, both of which are separated from -the product.
  • the period of time during which the reaction temperature is maintained may be widely variedperature should be maintained for not less than about one-half hour, and I prefer to maintain it for not less than about four hours to obtain a product of the highest activity.
  • the plating baths of the said Patent 1,681,509 are modified only by employing my novel addition agents in lieu of the addition agents, goulac, dextrin, starch, etc., mentioned therein.- While the plating processes described in the said Patent 1,681,509 lead to a bright, ha'rd, dense, and smooth deposit of cadmium, and while the invention,
  • Example XII A concentrated amaldacet produced according to Example X was employed as an addition agent in acyanide-cadmium bath made up as follows:
  • the bath of this example displayed good throwing power and a wide bright current density range.
  • the concentrated amaldacet of Example X may satisfactorily be employed, in widely varying amounts, but I usually prefer .to use between about eight-tenths and two grams per liter.
  • the proportion of the amaldacet used above, one and four-tenths grams per liter, is-about an optimum under the conditions of this example.
  • Example XIII 'I'he product of Example X obtained by reacting aldol and sodium cyanide. was used as an addition agent in a bath made up as follows:
  • Example XI I Grams per liter Sodium cyanide (NaCN) 130 Cadmium oxide (CdO) 43 Sodium sulfate (Nazsol) 50 Cobalt sulfate (COSOr'IHaO) 10 Addition agent 5
  • the concentrated product obtained in Example XI was employed as an addition agentin a bath made up as follows:
  • Example XV The amaldacet-containing product obtained in Example XI by the reaction of acetaldehyde and sodium cyanide was employed in a hath made up as follows:
  • Example XVI A concentrated amaldacet produced according to the process of Example X was employed as an addition agent in a-bath made upas follows:
  • This bath was used for plating several objects at a current density of twenty amperes per square foot
  • the deposit was extremely bright 'and smooth.
  • the number of grams of cadmium oxide in the above bath may be varied betweenfifteen and thirty-five and good results will be obtained. If the bath be too concentrated the deposit will not be entirely satisfactory.
  • the addition agent is used in about an optimum proportion for the conditions of this example, but I may advantageously employ from about five-tenths to about seventy-five hundredths gram per liter of this agent.
  • the other amaldacets above discussed can, of course, be employed in equivalent amounts.
  • chloroform soluble portion of these agents displays great activity as an addition agent, but promotes a streaked and somewhat unsatisfactory deposit.
  • the removal of the chloroform soluble portion is in the nature of a purification, but, in admixture with the other constituents of the addition agent, the chloroform soluble portion does not seem.to act in an appreciably deleterious manner, and it is ordinarily not expedient to efiect its separation.
  • amaldacets such as those produced according to the procedures of Examples I through IX, there are given below a few specific examples illustrating baths and processes employing such addition agents:
  • Example XVIII A cyanide-cadmium bath, of the type disclosedin the above mentioned Patent 1,681,509, was
  • Example XIX Using the amaldacet produced in Example 11 by reacting aldol and monoethanolamine, a cyanide-cadmium bath was made up as follows:
  • amaldacets are not readily soluble in cyanide-cadmium plating baths, and it is desirable that they be dispersed in the baths.
  • isoamketaldoresins generally, likewise, it is expedient to disperse the addition agent if dimculty is encountered in dissolving an optimum quantity.
  • the addition agents may be dispersed and their dissolution aided by adding them to a cyanide-cadmium bath in a suitable solvent, such as alcohol or acetone. It may sometimes be found desirable to reduce the addition agents to a finely divided state, or to use them in conjunction with such dispersing agents as saponin, gum arabic, and sulfite .cellulose waste.
  • Example XX The product of Example VI, prepared by treating aldol with ammonia, was added to a cyanidecadmiumbath in alcohol solution. The bath was made up as follows:
  • amketaldoresins derived by reacting an aldacet with ammonia, an amine, or cyanide have been discussed in some detail with reference to their preparation. their proper- I ties, and their applications as addition agents in cyanide-cadmium plating. 7 considered above are, in many respects, typical of the amketaldoresins.
  • amaldacets are, of course, derived from certain aliphatic ketaldones: the aldacets.
  • Emample XXI Equimolecular proportions of monoethanolamine and propionaldehyde were reacted at room temperature. A soluble resin was obtained which, when employed in baths such as those of Examples XII and XVI, displayed activity as an addition agent but was none too satisfactory.
  • Example XXII Methyl ethyl ketone was treated at room temperature with gaseous ammonia. The resulting reaction product displayed activity as an addition agent in cyanide-cadmium plating baths.
  • Example XXIII Five parts by weight of propionaldehyde were mixed with three parts by weight of sodium cyanide and ten parts by weight'of water. The mixture was maintained at a temperature of about 50 C. for two hours and then allowed to cool, There was a change in the appearance of The products thusthe mixture during the reaction period. The reaction product was a homogeneous, mobile liquid,
  • This reaction mixture constitutes a product of my invention.
  • the addition agent of this example was used in a cyanide-cadmium bath such as that of Example XII, the addition agent 01 this examplebeing used at a concentration of about 1.5 cc.
  • Example XXIV Diethyl ketone was treated with sodium cyanide according to the procedure of Example XXIII,
  • reaction mixture separated into two layers: a colorless lower layer, which is probably sodium cyanide solution, and an upper layer which is light yellow in color. While I may use both layers mixed together as an addition agent, I prefer to separate, and use, the upper layer.
  • the yellow upper layer was used in a cyanidecadmium bath of the type shown in Example XII at an optimum concentration of 5 cc. per liter. Excellent results were obtained.
  • the colorless lower layer displayed no appreciable activity as an addition agent.
  • Example XXV Methyl ethyl ketone was treated with sodium cyan de according to the procedure of Example XXIII and then allowed to stand a few days. The reaction mixture separated into a lower,
  • Example XXVI Diacetyl was treated with sodium cyanide according to the procedure of Example XXIII, and a homogeneous liquid was obtained.
  • the diacetyl-cyanide reaction product was employed at a concentration of 2 cc. per liter in a bath of the type shown in Example XII with good results.
  • Example XXV'II Methyl n-propyl ketone was treated with sodium cyanide according to the procedure of Example XXV.
  • a colorless upper layer and a color- Example XXVIII Acetone was treated with sodium cyanide according to the procedure of Example XXV.
  • Example XXIX Butyraldehyde was treated with sodium cyanide according to the procedure of Example XXV.
  • the two layers which formed are both active as addition agents, and I may use either or the mixture.
  • the lower layer gave good results as an addition agent at a concentration of 15cc. per liter in a cyanide-cadmium bath of the type shown in Example XII.
  • the upper layer produced even better results at a concentration of only 5 cc. per liter in a cyanide-cadmium bath of the same type.
  • Example XXX Hexadecoic aldehydes was treated with sodium cyanide according to the procedure of Example XXIII, the mixture of aldehyde and cyanide being maintained at about 50 C. for four hours. The reaction mixture was allowed to stand overnight and was found to have separated with a top layer of nearly black cyanide reaction product. It is noted that the original aldehyde was light yellow in color.
  • the lower layer had no appreciable effect as an addition agent in a cyanide-cadmium bath of the type shown in Example XII.
  • the upper layer was rather diflicultly soluble, but at its optimum concentrationof 5 cc. per liter, it served as an addition agent'in a cyanide-' cadmium bath of the same type.
  • the top layer being poorly soluble, it should be dispersed in the bath after the manner hereinbefore suggested.
  • a ketaldone When aliphatic ketaldones are used as starting materials, a ketaldone should be selected which contains at least two, carbon atoms.
  • Formaldehyde, with but one carbon atom, stands in a unique position with respect to aldehydes generally. Its dissimilarity to the other aldehydes is, of course, generally recognized.
  • aliphatic ketaldones contain more and more carbon atoms, they appear to become less desirable as starting materials for the production of amketaldoresins.
  • agents tend to be somewhat insoluble. They may, of course, be dispersed in the bath, but it is ordinarily preferable that the agents be readily soluble in the amounts required.
  • aliphatic ketaldones become somewhat less desirable as starting materials. Hexadecoic aldehyde, for instance, with sixteen carbon atoms led to the production of a relatively insoluble, though operative, amketaldoresin. I prefer, accordingly, to employ aliphatic ketaldones containing between two and nine carbon atoms. This terminology includes acetaldehyde, for example, as' a two carbon atom compound and citral as a nine carbon atom compound. I especially preferto employ those aliphatic ketaldones of two to nine carbon atoms Citral and citronellal, for example, with nine carbon atoms are quite satiswhich contain no more than two hydroxyl groups. I have found that it is not desirable that the aliphatic ketaldones contain carboxyl groups.
  • the elements sulfur and nitrogen are preferably absent from the aliphatic ketaldones which I employ as starting materials for the production of amketaldoresins.
  • n equals two or more, though preferably no more than nine; wherein a: is two or more;
  • ketaldones as ketoses andv aldoses.
  • Example XXXI Glucose was treated with an alkali metal cyanide by adding 123- grams of glucose to a cyanide solution made by adding 3.3 grams of sodium cyature was maintained at about 45 to 50 C. for eighteen hours and was agitatedintermittently. During the period of treatment, a faint odor of ammonia was observed.
  • glucose was employed as an addition agent for cyanide-cadmium baths of the same type and in the same concentrations as were the products of this exthan its cyanide-reaction product. It is noted that the baths containing-glucose were lightyellow in color.
  • amketaldoresins prepared from the aliphatic ketaldones have been discussed above in some detail, and it is now proposed to discuss briefly the preparation 01 amketaldoresins from carbocyclic ketaldones.
  • amketaldoresins may be prepared by the treatment of carbocyclic ketaldones with an amo or cyanide according to procedures similar to those above discussed.
  • Example XXXII Equimolecular proportions of monoethanolamine and benzaldehyde were reacted at room temperature. The product displayed activity as an addition agent in a cyanide-cadmium plating bath of the type shown in Example XII.
  • Example XXXIII Gaseous ammonia was passed into benzaldehyde until the reaction was complete. The amketaldoresin produced was found to have activity as an addition agent in a cyanide-cadmium bath of the type shown in Example XII.
  • Example XXXII/ Glucose itself was much less effective the cyanide solution a precipitate of some relatively insoluble material formed. After a few hours most of this precipitate had dissolved.
  • reaction mixture was employed quite successfully with a cyanide-cadmium bath of the type shown in Example XII.
  • Benzaldehyde is known to form benzoin in alkaline solution according to the following:
  • ketaldones which do not-contain a carboxyl group and which do not contain sulfur.
  • Example xxxvn Six and one-half grams of freshly distilled furfural was added to a sodium cyanide solution made up of 3.3 grams of sodium cyanide in 10 cubic centimeters of water. Quickly there was produced a red, heterogeneous mixture which 1 was then maintained for six hours at 45 to 50 I C. During the reaction period, a faint odor of ammonia was observed. At the end of the six hours, the mixture ha'd reacted to form a black, tarry, lower layer and a brown, supernatant liquid. The black lower layer is effective as an addition agent, and it constitutes a product of this invention.
  • reaction mixture obtained above was treated with an excess of dilute sulfuric acid over that required to react with excess sodium cyanide,
  • Example X After the procedure of Example X. Upon the addition of acid, a violent reaction took place, and a small amount of a black, liquid tar separated from the upper layer and joined the tar already at the bottom of the reaction receptacle.
  • agentsof thisexample are rather difiicultly soluble, and it is preferred to add them to cya- 40 nide-cadmium baths in a suitable solvent such as alcohol.
  • a suitable solvent such as alcohol.
  • Furfural was employed as an addition agent for,
  • cyanide-cadmium baths of the type used in Ex- 5 ample XII, in various amounts up to about ten grams per liter. After standing for several hours, the baths becamevery dark in color, and appeared black. By strong transmitted light, a small sample of one such bath appeared tohave a dark,
  • furfural-cyanide products of this example are not merely condensation products in al-' kaline solution is evidenced by their similarity to the products of Example X, by the fact that the odor of ammonia can be detected during the reaction, and by the fact that resins formed by furwere added. A dark-brown, opaque solution was obtained.
  • the furfural-alkali resin was employed in various amounts as an addition agent for cyanidecadmlum baths of the type shown in Example XII as well as in baths of a similar type which contained no such brightening agent as cobalt or nickel.
  • the baths were a clear, dark-red in color. While these materials displayed a slight activity,
  • the isoamketaldoresins include derivatives of the amketaidoresins, such as their hydrogenation, oxidation, sulfurization, and halogenation products. These derivatives are, of course, characterized by their s-milarity to the amketaldoresins, and by the fact that they contain nitrogen.
  • isoamaldacets Similar derivatives of the amaldacets, together with the amaldacets, are termed isoamaldacets.- The relationships of the isoamketaldoresins, isoamaldacets, amketaldoresins, and amaldacets have been discussed hereinbefore, and, as has been noted above, the relationships are clearly illustrated in the drawing.
  • Example XXXVIII (1) Grams per liter Sodium cyanide (NaCN) 130 Cadmium'oxide (CdO) 43 Sodium sulfate '(Na2SO4) 50 Cobalt sulfate (C0SO4-7H2O) 10 Addition agent 1.2
  • the reduced solution may, of course, be used after the manner in which the aldacet reaction product was used in Examples XIII and XVII.
  • the reduced amaldacets are slightly more soluble than the untreated amaldacets, and are slightly more active as addition agents in cyanide-cadmium plating.
  • Example XL The orotonaldehyde-monoethanolamine reac tion product of Example I was dissolved in alkaline cyanide solution, and zinc dust was added to reduce the product. The product gave results comparable with those obtained in Example XVIII when employed in a similar cyanidecadmium bath.
  • Example XLI Following the procedure of the, above Example XXXVIII, the propionaldehyde-sodium cyanide reaction product of Example XXIII, was reduced by the use of zinc dust. The reduced product gave results comparable to those of Example XXIII when employed in a similar cyanidecadmium bath.
  • Example XLII Following the procedure of the above Example XXXVIII, the benzaldehyde-sodium cyanide reaction product of Example XXXIV was reduced. The reduced product displayed activity as an addition agent in cyanide-cadmium baths of the types shown above.
  • amketaldoresins "disclosed hereto-- iore may be reduced in manners similar to those shown in the above illustrative Examples XXXVIII thru XLII.
  • zinc dust was employed as a reducing agent largely because of its convenience, but as will be evident, other reducing agents may satisfactorily be employed.
  • I may, for instance, use a reducing agent such as sodium sulfite. It will be understood that the extent of reduction of the amketaldoresins may be widely varied, the hydrogen presumably saturating some or all of the double bonds.
  • Example XLIII The cyanide reaction product of the above Example X was subjected to oxidation by adding thereto ten cc. per liter of 100 volume (30% by weight) hydrogen peroxide. The product thus obtained was concentrated by acidification with sulfuric acid according to the procedure of the above Example X.
  • cyanide-cadmium plating baths were made up as follows:
  • the oxidized amaldacets like the reduced amaldacets, are slightly more soluble and slightly more effective as addition agents in cyanide-cadmium plating baths than the untreated amketaldoresins from which they are derived.
  • the reduced and oxidized amaldacets are very similar in theirproperties, as has been noted above, and they may advantageously be employed under similar conditions and in similar amounts.
  • Example XLI V The reaction product of Example In was oxidized, according to the procedure of the above Example XLIII, and the oxidized product concentrated. The oxidized reaction product and the concentrated product produced results comparable with those obtained above with the addi-- tion agent of Example XI.
  • Example XLV Example XLVI The propionaldehyde-sodium cyanide reaction product of Example IQHII yielded, upon oxidation, a product very satisfactory as an addition agent when used in cyanide-cadmium baths of the type shown above.
  • Example XLVII Following the procedure of the above Example XLIII, the benzaldehyde-sod-ium cyanide reaction product of Example XXXIV was oxidized. The oxidized product displayed activity as an addition agent in cyanide-cadmium baths of the types above shown.
  • amketaldoresins disclosed herein may similarly be oxidized to produce addition agents for cyanide-cadmium plating.
  • amketaldoresins may be modified in a number of other ways, as will be evident to those skilled in the art, without a destruction of their properties as addition agents. They may, for instance, be treated with hydrogen sulfide, in which event a somewhat inferior addition agent is obtained.
  • the amketaldoresins moreover,
  • the derivatives ' might be halogenated.
  • the derivatives ' should contain nitrogen, and it is desirable that they be somewhat soluble. They are, of course, characterized by activity as addition agents in cyanide-cadmium plating baths, and many such derivatives of the amketaldoresins may be prepared which are suitable for my purposes.
  • prereacted addition agents prepared by reacting a ketaldone with an amo in alkaline solution.
  • ketaldone refers, of course, to aldehydes and ketones as is set forth in detail hereinbefore, and the term amo refers to ammonia and amines as in United States Patent 1,961,890 and as set forth in detail hereinbefore.
  • a pre-reacted addition agent prepared by reacting a ketaldone with an amo in alkaline solution.
  • a cyanide-cadmium plating composition containinga pre-reacted addition agent prepared by reacting a ketaldone with an amo in alkaline solution.
  • a cyanide-cadmium plating composition containing a pre-reacted addition'agent prepared by reacting an aliphatic ketaldone with an amo in alkaline solution.
  • a process for the electrodeposition of cadmium comprising depositing cadmium from a cyanide-cadmium bath in the pres.- ence of a pre-reacted addition agent prepared by reacting a ketaldone with an amo in alkaline solution.
  • a cyanide-cadmium plating composition containing a pre-reacted addition agent prepared by reacting an aliphatic aldehyde selected from the group consisting of acetaldehyde, aldol, crotonaldehyde, and paraldol with an amo in alkaline solution.
  • a process for the electrodeposition of cadmium comprising depositing cadmium from a cyanide-cadmium bath in the presence ofan addition agent comprising an amketaldo'resin, an amketaldoresin being, as herein set forth,'a pre-reacted addition agent prepared by reacting a ketaldone with an amo in alkaline solution.

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US45404A 1935-10-17 1935-10-17 Electrodeposition of cadmium Expired - Lifetime US2085750A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2485565A (en) * 1944-07-24 1949-10-25 Poor & Co Cadmium plating
US2497806A (en) * 1945-12-12 1950-02-14 Lea Mfg Company Electrodeposition of cadmium

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2485565A (en) * 1944-07-24 1949-10-25 Poor & Co Cadmium plating
US2497806A (en) * 1945-12-12 1950-02-14 Lea Mfg Company Electrodeposition of cadmium

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