US2332497A - Determination of sodium hydroxide in presence of the aluminate - Google Patents
Determination of sodium hydroxide in presence of the aluminate Download PDFInfo
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- US2332497A US2332497A US373323A US37332341A US2332497A US 2332497 A US2332497 A US 2332497A US 373323 A US373323 A US 373323A US 37332341 A US37332341 A US 37332341A US 2332497 A US2332497 A US 2332497A
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- aluminate
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- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 title description 103
- 150000004645 aluminates Chemical class 0.000 title description 23
- 239000000243 solution Substances 0.000 description 66
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 36
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 29
- 229910001388 sodium aluminate Inorganic materials 0.000 description 29
- 239000002253 acid Substances 0.000 description 21
- 238000000034 method Methods 0.000 description 21
- 230000003472 neutralizing effect Effects 0.000 description 19
- 239000011775 sodium fluoride Substances 0.000 description 18
- 235000013024 sodium fluoride Nutrition 0.000 description 18
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 15
- 239000003513 alkali Substances 0.000 description 14
- -1 alkali metal aluminate Chemical class 0.000 description 12
- 229910052783 alkali metal Inorganic materials 0.000 description 11
- KJFMBFZCATUALV-UHFFFAOYSA-N phenolphthalein Chemical compound C1=CC(O)=CC=C1C1(C=2C=CC(O)=CC=2)C2=CC=CC=C2C(=O)O1 KJFMBFZCATUALV-UHFFFAOYSA-N 0.000 description 11
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 9
- 230000001172 regenerating effect Effects 0.000 description 9
- 239000000126 substance Substances 0.000 description 9
- 239000012670 alkaline solution Substances 0.000 description 7
- 239000003599 detergent Substances 0.000 description 7
- 239000011734 sodium Substances 0.000 description 7
- 229910052708 sodium Inorganic materials 0.000 description 7
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 6
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 6
- WDIHJSXYQDMJHN-UHFFFAOYSA-L barium chloride Chemical compound [Cl-].[Cl-].[Ba+2] WDIHJSXYQDMJHN-UHFFFAOYSA-L 0.000 description 5
- 229910001626 barium chloride Inorganic materials 0.000 description 5
- 239000003518 caustics Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 5
- 230000007935 neutral effect Effects 0.000 description 5
- 238000004448 titration Methods 0.000 description 5
- 150000007513 acids Chemical class 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 230000001376 precipitating effect Effects 0.000 description 4
- 150000004760 silicates Chemical class 0.000 description 4
- 239000004115 Sodium Silicate Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 3
- 229910052911 sodium silicate Inorganic materials 0.000 description 3
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 230000001476 alcoholic effect Effects 0.000 description 2
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 2
- 235000013405 beer Nutrition 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 235000013305 food Nutrition 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- KVOIJEARBNBHHP-UHFFFAOYSA-N potassium;oxido(oxo)alumane Chemical compound [K+].[O-][Al]=O KVOIJEARBNBHHP-UHFFFAOYSA-N 0.000 description 2
- 239000001488 sodium phosphate Substances 0.000 description 2
- 239000012086 standard solution Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 2
- 229910000406 trisodium phosphate Inorganic materials 0.000 description 2
- 235000019801 trisodium phosphate Nutrition 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical class OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 1
- LEHOTFFKMJEONL-UHFFFAOYSA-N Uric Acid Chemical compound N1C(=O)NC(=O)C2=C1NC(=O)N2 LEHOTFFKMJEONL-UHFFFAOYSA-N 0.000 description 1
- TVWHNULVHGKJHS-UHFFFAOYSA-N Uric acid Natural products N1C(=O)NC(=O)C2NC(=O)NC21 TVWHNULVHGKJHS-UHFFFAOYSA-N 0.000 description 1
- 150000001339 alkali metal compounds Chemical class 0.000 description 1
- 229910000318 alkali metal phosphate Inorganic materials 0.000 description 1
- 238000012863 analytical testing Methods 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 159000000009 barium salts Chemical class 0.000 description 1
- 235000013361 beverage Nutrition 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910021538 borax Inorganic materials 0.000 description 1
- 150000001642 boronic acid derivatives Chemical class 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- ZZUFCTLCJUWOSV-UHFFFAOYSA-N furosemide Chemical compound C1=C(Cl)C(S(=O)(=O)N)=CC(C(O)=O)=C1NCC1=CC=CO1 ZZUFCTLCJUWOSV-UHFFFAOYSA-N 0.000 description 1
- 230000002070 germicidal effect Effects 0.000 description 1
- 159000000011 group IA salts Chemical class 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- STZCRXQWRGQSJD-GEEYTBSJSA-M methyl orange Chemical compound [Na+].C1=CC(N(C)C)=CC=C1\N=N\C1=CC=C(S([O-])(=O)=O)C=C1 STZCRXQWRGQSJD-GEEYTBSJSA-M 0.000 description 1
- 229940012189 methyl orange Drugs 0.000 description 1
- 239000008267 milk Substances 0.000 description 1
- 210000004080 milk Anatomy 0.000 description 1
- 235000013336 milk Nutrition 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 230000005180 public health Effects 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 150000003388 sodium compounds Chemical class 0.000 description 1
- GCLGEJMYGQKIIW-UHFFFAOYSA-H sodium hexametaphosphate Chemical compound [Na]OP1(=O)OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])OP(=O)(O[Na])O1 GCLGEJMYGQKIIW-UHFFFAOYSA-H 0.000 description 1
- 235000019982 sodium hexametaphosphate Nutrition 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 239000004328 sodium tetraborate Substances 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000001577 tetrasodium phosphonato phosphate Substances 0.000 description 1
- 229940116269 uric acid Drugs 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/16—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using titration
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/15—Inorganic acid or base [e.g., hcl, sulfuric acid, etc. ]
Definitions
- alkali aluminate My invention is equally well applicable to caustic alkali solutions in which the caustic alkali is sodium or potassium hydroxide and the corresponding contaminating compound is sodium or potassium aluminate.
- Sodium hydroxide is the caustic alkali most commonly used commercially in detergent, cleaning and washing solutions. with metallic aluminum, a chemical reaction takes place whereby some or all of the alkali is converted into sodium (or potassium) aluminate, thereby decreasing the alkaline intensity of the solution and its corresponding detergent and germicidal ability.
- My invention is based upon the discovery that the addition of sodium fluoride to such solutions which have become contaminated with sodium or potassium aluminate, results in a substantial increase in the alkalinity thereof; in fact, in tripling the alkalinity or hydroxyl ion concentration of.
- alkaline cleaning for the food and beverage industries, food containers, beer bottles, milk bottles, and numerous other articles are washed in alkaline solutions containing sodium or potassium hydroxide in combination with alkali metal salts, such as trisodium phosphate,
- alkalies such as the alkali metal phosphates, carbonates, bicarbonates, borates and silicates, are used in sodium hydroxide to improve its rinsing properties and to condition the water for more effective cleaning.
- alkali detergent solutions when coming in contact with metallic aluminum, such as that found in metal foil labels, bottle caps, utensils and the like, reacts to form alkali metal aluminate according to the following equation:
- the other alkali metal salts present also react with the aluminum in a similar manner, forming additional aluminate.
- the presence of the aluminatein such solutions is undesirable, first, because it is a weaker and much less effective alkali, thus depreciating the alkaline capacity or hydroxyl ion concentration of the solution as a whole; and secondly, because it is impossible, with analytical testing methods heretofore known, reliably to determine the actual amount of alkali metal hydroxide present in the solution.
- Method (1) is accurate for sodium hydroxide solutions, and, since sodium hydroxide-is seldom used alone,.this method is not accurate enough for accepted use.
- Method (2) is accurate only ior solutions con taining sodium hydroxide in combination with sodium carbonate and/or trisodium phosphate.
- Method (3) has been most widely used and for general use is the most accurate, but it still is not sufllciently accurate for solutims contaminated with sodium aluminate.
- Such a chemical equivalent amount of the sodium fluoride is, oicourae, estimateduponthebasisoitheprobtetrasodium pyrophosphatc, sodium hexametaphosphate, borax, sodium bi-carbonate, sodium silicate and sub-silicates.
- the solution is then titrated with an acid solution of known strength using a few drops 01' 0.5 percent alcoholic phenolphthalein solution as the indicator.
- 01' 0.5 percent alcoholic phenolphthalein solution as the indicator.
- the sodium aluminate can be obtained by multiplyins the milliliters of acid used in themond titration by a constant factor. factor is derived as inflows:
- the above factor is converted into terms of per cent of sodium aluminate by multiplying it by 100 and dividing by 10.3, viz.
- the percent of sodium aluminate in our illustrative example is thus calculated as follows:
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- Life Sciences & Earth Sciences (AREA)
- Molecular Biology (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
Description
Patented Oct. 26, 1943 UNITED STATES PATENT OFFICE DETERMINATION OF SODIUM HYDROXIDE IN PRESENCE OF THE ALUIVHNATE Perle N. Burkard, Wyandotte, Mich., assignor, by mesne assignments, to Wyandotte Chemicals Corporation No Drawing. Application January 6, 1941, Serial No. 373,323
8 Claims.
their conditions and circumstances of usage, have become contaminated with an alkali aluminate. My invention is equally well applicable to caustic alkali solutions in which the caustic alkali is sodium or potassium hydroxide and the corresponding contaminating compound is sodium or potassium aluminate. Sodium hydroxide, however, is the caustic alkali most commonly used commercially in detergent, cleaning and washing solutions. with metallic aluminum, a chemical reaction takes place whereby some or all of the alkali is converted into sodium (or potassium) aluminate, thereby decreasing the alkaline intensity of the solution and its corresponding detergent and germicidal ability.
My invention is based upon the discovery that the addition of sodium fluoride to such solutions which have become contaminated with sodium or potassium aluminate, results in a substantial increase in the alkalinity thereof; in fact, in tripling the alkalinity or hydroxyl ion concentration of.
the aluminate. This discovery is primarily of a two-fold utility.
First it provides a new convenient and reliable analytical method for determining both the caustic alkali and aluminate content of alkaline solutions which have become contaminated with alkali metal aluminate; and secondly, as already indicated it provides a convenient method of regenerating the alkalinity of such solutions of deficient alkaline capacity.
In the art of alkaline cleaning for the food and beverage industries, food containers, beer bottles, milk bottles, and numerous other articles are washed in alkaline solutions containing sodium or potassium hydroxide in combination with alkali metal salts, such as trisodium phosphate,
As such solutions come in contact ingredient in bottle washing compounds. Various other alkalies, such as the alkali metal phosphates, carbonates, bicarbonates, borates and silicates, are used in sodium hydroxide to improve its rinsing properties and to condition the water for more effective cleaning.
Such alkali detergent solutions, when coming in contact with metallic aluminum, such as that found in metal foil labels, bottle caps, utensils and the like, reacts to form alkali metal aluminate according to the following equation:
The other alkali metal salts present also react with the aluminum in a similar manner, forming additional aluminate. The presence of the aluminatein such solutions is undesirable, first, because it is a weaker and much less effective alkali, thus depreciating the alkaline capacity or hydroxyl ion concentration of the solution as a whole; and secondly, because it is impossible, with analytical testing methods heretofore known, reliably to determine the actual amount of alkali metal hydroxide present in the solution. It is, therefore, the general object and nature of my invention to provide a method for regenerating the alkalinity of alkaline,.detergent soluof my analytical method may be accurately determined in dirty and soil-contaminated solutions, To the accomplishment of the foregoing and related ends, said invention, then consists of the steps hereinafter fully described and particularly pointed out in the claims.
The following description sets forth in detail one approved method of carrying out the invention, such disclosed method, however, constituting but one of the various ways in which the principle of the invention may be used. Although, as above indicated, the invention is equivalently applicable to alkali metal compound solutions in which the hydro des d c nating aluminates are those of sodium orpotasslum, the followingdetailed description will suitably, and for the sake of convenience, be confined to the sodium compounds.
As previously pointed out, the contamination oi alkali, detergent solutions with sodium aluminate has presented a serious problem in the art. The seriousness of this problem can be appreciated by considering that the aluminum labels from 210,000 average iii-ounce beer bottles will completely convert all the sodium hydroxide in 600 gallons of a 3 percent sodium hydroxide solution into sodium aluminate, a milder and much less eflective alkali. In addition, by the methods commonly used for titrating alkaline solutions, this solution will still show a 3 percent sodium hydroxide contentwhen no sodium hydroxide is present.
For operating efllciency and to comply with certain public health regulations, it is desirable to maintains deflnite sodium hydroxide content in the solution. Some State laws. for instance, require a 3 percent sodium hydroxide content. To do this, a reliable method of testing the solution must be employed. The methods used in the pasthave been:
(1) By determining the specific gravity of the solutions with a hydrometer and reading the sodium hydroxide content from a conversion table.
(2) By the double titration method employing a standard acid solution, phenolphthalein indicator, and methyl orange indicator and calculating the sodium hydroxide content.
(3) By precipitating the other alkaline salts with neutral barium chlorideand titrating the sodium hydroxide which remains in solution with a standard acid using phenolphthalein indicator solution.
Method (1) is accurate for sodium hydroxide solutions, and, since sodium hydroxide-is seldom used alone,.this method is not accurate enough for accepted use.
Method (2) is accurate only ior solutions con taining sodium hydroxide in combination with sodium carbonate and/or trisodium phosphate.
Method (3) has been most widely used and for general use is the most accurate, but it still is not sufllciently accurate for solutims contaminated with sodium aluminate.
1'. have discovered that the alkalinity of a soduim aluminate solution above a pH of 8.2 can be tripled by adding an excess of sodium fluoride, preferably in the form oi. a powder. The chemicalreactionthattakupiacecannotatthis time be fully explained. Sodium aluminate, NaAlOz, reacts inthe presence of sodium fluoride as it its iorrnula were NasAlOa. Thus, by adding a chemical equivalent amount of powdered sodium fluoride to a solution containing sodium aluminate, the spent alkalinity due to the presence oi the sodium aluminate is regenerated. Such a chemical equivalent amount of the sodium fluoride is, oicourae, estimateduponthebasisoitheprobtetrasodium pyrophosphatc, sodium hexametaphosphate, borax, sodium bi-carbonate, sodium silicate and sub-silicates. The solution is then titrated with an acid solution of known strength using a few drops 01' 0.5 percent alcoholic phenolphthalein solution as the indicator. When the end point is reached at a pH of approximately 8.2, only the alkalinities or the sodium hydroxide and the sodium aluminate have been neutralized. The other alkaline materials have reacted with the barium chloride precipitating barium salts and forming neutral sodium chloride. If at this point an excess, usually about 0.5 to 1.0 gram for every 10 ml. of alkaline solution, of sodium fluoride powder be added, the solution will again turn pink due to the alkalinity formed by the reaction of the aluminate and the sodium fluoride. I have discovered that this increase in alkalinity upon the addition of the sodium fluoride powder is equal to twice the alkalinity oi the sodium aluminate present in the original solution.
Applying the above-stated facts to chemical analysis, I have discovered that, by titrating an aliquot portion of an alkaline solution with an acid of known strength in the presence of barium chloride and phenolphthalein indicator solution, the number of milliliters of acid used in this titration minus 5 the number of milliliters of acid required to reach the second end point after the addition of sodium fluoride powder is equal tothe number of milliliters of acid required to neutralize the sodium hydroxide present in the aliquot portion of the alkaline solution. If 1.000 normal acid were used, each milliliter of acid is equivalent to 0.040 gram 01' sodium hydroxide.
For example, in titrating 10 milliliters of an alkaline solution having a specific gravity of 1.03
to which barium chloride has been added in ex-' cess of that amount required to precipitate carbonates, phosphates, etc., with 1.000 normal suli'uric acid using 0.5% alcoholic phenolphthalein as the indicator solution; 16.5 milliliters of the acid were required to reach the end point. After the addition of sodium fluoride, 10.4 milliliters of additional acid was required to reach the second end point. Then:
(16.5- 10.4/2) X .040X 100 "1o 1.o3 In practical fleld testing. I employ 2.56 normal sulfuric acid and titrate lo-milliliter portions 01 the cleaning solution. The use or 2.58 normal acid in place of 2.50 normal acid compensates apable amount or sodium aluminate present and is added in excess thereoiinorder to insure asate the preceding paragraph then become:
1st end point. 6.44 milliliters of 2.58 8 acid 2nd end point at. the addition or sodium fluoride---- 4.07 milliliters of 2.56 8 acid %NaOH=6.44--4.07/2=4.4
The sodium aluminate can be obtained by multiplyins the milliliters of acid used in themond titration by a constant factor. factor is derived as inflows:
Since all oi the acid used in the second titration is used in titrating the alkali liberated by the re- I action oi sodium aluminate and sodium fluoride, it means that 1 molecule of sulphuric acid is regfggX .l255=0.104ii grams N aAlO;
The above factor is converted into terms of per cent of sodium aluminate by multiplying it by 100 and dividing by 10.3, viz.
The percent of sodium aluminate in our illustrative example is thus calculated as follows:
% NaAlOz=L019 X 4.07
In some instances, it might beyfound necessary to adjust the above derived factor of 1.019 to compensate for the presence of other chemicals in solution and in practical field tests. This ad- .iustment can be made in the factor by titrating a number of solutions of known strength and calculating the factor.
'The method herein described works equally well for solutions from their freezing to their boiling points and for dirty solutions, as well as clean solutions. To overcome the necessity of filtering dirty solutions, I have purposely used barium chloride and sulfuric acid to form an internal, white background oi white barium sulfate to make indicator color changes easily visible.
It will be apparent to those skilled in the art that equivalent indicators other than the phenolphthalein indicator hereirabove mentioned may be employed to indicate the pr p end point during the neutralizing or titrating steps of my analytical method.
By the 'same token, equivalent neutralizing acids, made up in standard solutions, may likewise be employed in lieu of the standard sulfuric acid solutions hereinabove described.
The above-described method for determinin the caustic alkali and sodium aluminate content of solutions is highly accurate and reliable for practically all alkaline detergents encountered in the fleld, even those containing silicates in the amount of up to 1% sodium silicate. Above that amount, silicates will have some eifect upon the accuracy of the sodium hydroxide content determinations. but any such higher percentage of sodium silicate is rarely encountered in solutions contaminated with aluminum, for the simple reason that detergents containing silicates are not ordinarily employed if the solutim is likely to be placed in contact with aluminum.
Other modes of applying the principle of my invention may be employed instead of the one explalned, change being made as regards the method herein disclosed, provided the step or steps stated by any of the following claims 01' the equivalent of such stated step or steps be employed.
1, therefore, particularly pointout and distinctly claim as my invention:
1. The method of determining the amount of alkali metal hydroxides in solutions thereof contaminated with alkali metal aluminate, consisthis in the steps of neutralizing the alkalinity of said hydroxides and said aluminate, adding sodium fluoride thereto in an amount suiilcient to react completely with the aluminate, thereby regenerating the alkalinity of said aluminate to twice its original amount, and then neutralizing the resultant solution.
2. The method of determining the amount of sodium hydroxide in solutions thereof contaminated with sodium aluminate, consisting in the 7 steps of neutralizing the alkalinity of said hy-' droxide and said aluminate, adding sodium fluoride thereto in an amount sufllcient to react completely with the sodium aluminate, thereby regenerating the alkalinity of said aluminate to twice its original amount, neutralizing the resultant solution, and measuring the sodium hydroxide chemical equivalent amount of neutralizing reagent required in each of the aforesaid neutralizing steps.
3. The method of determining the amount of sodium hydroxide and sodium aluminate present in the same solution, consisting in the steps of neutralizing the alkalinity of said hydroxide and said aluminate, adding sodium fluoride thereto in an amount suflicient to react completely with the sodium aluminate. thereby regenerating the alkalinity 01 said aluminate to twice its original amount. neutralizing the resultant solution, and measuring the sodium hydroxide chemical equivalent amount of neutralizing reagent required in each of the aforesaid neutralizing steps.
4. The method of determining the amount of sodium hydroxide in a solution containing alkali metal salts of weak acids in addition thereto, and contaminated with sodium aluminate, consisting in the steps of precipitating said alkali metal salts. whereby the sodium hydroxide and sodium aiuminate remain in solution, neutralizink the alkalinity of said hydroxide and said aluminate, adding sodium fluoride thereto in an amount sufiicient to react completely with the sodium aluminate, thereby regenerating the alkalinity of said aluminate to twice its original amount,- and then neutralizing the resultant solution.
5. The method of determining the amount 0 sodium hydroxide in a solution containing alkali metal salts of weak acids in addition thereto and contaminated with sodium aluminate, consisting in the steps of precipitating said alkali metal salts, whereby the sodium hydroxide and sodium aluminate remain in solution, neutralizing .the
alkalinity of said hydroxide and said aluminate, adding sodium fluoride thereto in an amount sumcient to react completely with the sodium aluminate, thereby regenerating the alkalinity of said aluminate to twice its original amount,
then neutraliziing the resultant solution, and measuring the sodium hydroxide chemical equivalent amount of neutralizing reagent required in each 'of the aforesaid neutralizing steps.
6. The method of determining the amount of sodium hydroxide and. sodium aluminate, both present in the same solution, and in which alkali with the sodium aluminate, thereby regeneratin the alkalinity of said aluminate to twice its original amount, neutralizing the resultant solution,
and measuring the sodium hydroxide chemical equivalent amount of neutralizing agent required in each of the aforesaid neutralizing steps.
7. The method of determining the amount of sodium hydroxide in a solution containing alkali metal salts of weak acids in addition thereto and contaminated with sodium aluminate, consisting in the steps of adding barium chloride to said solution in excess of the amount required to precipitate said alkali metal salts. thereby leaving the sodium hydroxide and sodium aluminate in solution, adding an indicator to said solution and titrating to the neutral end point with a standard solution of sulfuric acid, thereby forming a white background of barium sulphate in the solution, adding sodium fluoride to the solution in an amount suiiicient to react completely with the sodium aluminate, thereby regenerating the alkalinity of said aluminate to twice its original amount, and again. titrating to the neutral 20 normal solution of sulfuric acid, thereby forming a white background of barium sulphate in the solution, adding sodium fluoride to the solution in an amount suiiicient to react completely with the sodium aluminate. thereby regenerating the alkalinity of said aluminate to twice its original amount, and again titrating to the neutral end point with a 2.58 normal solution of sulfuric acid and measuring the respective amounts of said sulfuric acid solution required in both of the aforesaid titration steps.
PERLE N. BURKARD.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US373323A US2332497A (en) | 1941-01-06 | 1941-01-06 | Determination of sodium hydroxide in presence of the aluminate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US373323A US2332497A (en) | 1941-01-06 | 1941-01-06 | Determination of sodium hydroxide in presence of the aluminate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2332497A true US2332497A (en) | 1943-10-26 |
Family
ID=23471906
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US373323A Expired - Lifetime US2332497A (en) | 1941-01-06 | 1941-01-06 | Determination of sodium hydroxide in presence of the aluminate |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2332497A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2811426A (en) * | 1955-02-21 | 1957-10-29 | Aluminum Co Of America | Treating aluminum surfaces |
| US2965457A (en) * | 1957-05-01 | 1960-12-20 | Du Pont | Process for etching aluminum |
| US2987483A (en) * | 1956-07-02 | 1961-06-06 | Pennsalt Chemicals Corp | Cleaning composition |
| US4617063A (en) * | 1984-12-04 | 1986-10-14 | Morris Brian V | Cleaning silver |
-
1941
- 1941-01-06 US US373323A patent/US2332497A/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2811426A (en) * | 1955-02-21 | 1957-10-29 | Aluminum Co Of America | Treating aluminum surfaces |
| US2987483A (en) * | 1956-07-02 | 1961-06-06 | Pennsalt Chemicals Corp | Cleaning composition |
| US2965457A (en) * | 1957-05-01 | 1960-12-20 | Du Pont | Process for etching aluminum |
| US4617063A (en) * | 1984-12-04 | 1986-10-14 | Morris Brian V | Cleaning silver |
| AU569019B2 (en) * | 1984-12-04 | 1988-01-14 | Morris, B.V. | Cleaning silver or silver-plated articles |
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