Ashta Chemicals Inc.

Conversion Tables

The conversion factors below are calculated on a basis of 100% purity. To convert compound A into an equivalent amount of compound B, multiply by the A to B factor. To convert compound B into compound A, multiply by the B to A factor.
Compound A	Compound B	A to B	B to A
K KOH K₂CO₃ KCl K₂SO₄	K₂O	1.205 0.840 0.682 0.632 0.541	0.831 1.191 1.467 1.583 1.850
K₂CO₃ KHCO₃	CO₂	0.318 0.220	3.141 4.545
K₂CO₃	KOH	0.812	1.232
K₂SO₄	SO₄=	0.551	1.814
Cl- K₂SO₄ KNO₃	KCl	2.103 0.856 0.737	0.479 1.169 1.356
Conversion Factor A to B = (Equivalent weight B) / (Equivalent weight A) Conversion Factor B to A = 1 / (Conversion Factor A to B)

Equivalent Conductance of caustic potash solutions
°C	°F		Reference
18	64.4	238.7	(40)
18	64.4	239.0	(3)
25	77.0	274.9	(24)
25	77.0	274.9	(16)(17)
25	77.0	283.9	(33)
25	77.0	285.46	(32)
90	194.0	599.0	(8)

Heat of Neutralization of caustic potash and caustic soda solutions at 20°C
Mol Acid / 100 Mol H₂O	Mol KOH / 100 Mols H₂O (Calories)	Mol NaOH / 100 Mols H₂O (Calories)
HCl	14014	13895
HBr	13988	13843
HI	13915	13779
HNO₃	14086	13836

Heat of Solution
°C	°F	Mol of Water per Mol KOH	Heat of Solution kcal/mol	B.T.U. per lb. KOH	Reference
11.4	52.5	260	12.46	399.9	(5)
18.0	64.4	250	13.29	426.5	(62)
100	212	260	16.8	539.2	(6)

Physical Constants
Chemical Name	Potassium Hydroxide
Chemical Formula	KOH
Molecular Weight	56.1
Crystalline Form	Rhombic
Specific Gravity	2.044
Melting Point	380°C (716°F)
Boiling Point @ 760 mm Hg pressure	1,320°C (2,480°F)
Heat of Fusion	28.6 cal/g
Heat of Solution @ 18°C	+13.29 Kg-cal per 250 moles H₂O
Solubility in Various Solvents
Cold Water @ 0°C	97 grams per 100 mL water
Hot Water @ 100°C	178 grams per 100 mL water
Organic Solvents	Very soluble in alcohol and ether
Inorganic Solvents	Insoluble in NH₃

Chemical Reactions
Moisture	KOH is deliquescent and absorbs moisture from the air until it is dissolved. Heat is evolved during the dissolving process.
pH	KOH solutions are strongly alkaline and have a pH value greater than 12.
Carbon Dioxide	In the presence of moisture, KOH reacts with CO₂ from the air to form K₂CO₃ and KHCO₃.
Animal and Plant Fibers	All living tissues, especially animal fibers such as wool, leather, silk and human skin are rapidly dissolved by KOH and thus destroyed. Plant fibers like cotton and rubber are less readily attacked.
Heavy Organic Compounds	In order to make heavy organic compounds soluble in water, parts of the KOH molecule are added by means of replacement and saponification reactions.
Inorganic Compounds	KOH reacts with inorganic acids and acidic anhydrides to form potassium salts. With metals it forms insoluble hydroxides.

Dilution of Liquid Caustic Potash
The following problems make use of the fundamental equations: DENSITY=WEIGHT/VOLUME Concentration 1 x Volume 1 = Concentration 2 x Volume 2
EXAMPLE 1: Dissolving Solid Forms of KOH
Problem What amount of ASHTA flake caustic potash (90% KOH) and what amount of water must be added in order to obtain 20% KOH solution?	Solution Refer to the Dilution Chart below since 90% KOH and water (0% KOH) are involved, use line A, which connects these two points. Follow the 20% line vertically until it intersects line A. Read horizontally left and right from the point of intersection. 22 lbs. of strong solution (90% KOH) must e added to 78 lbs. (9.38 gallons) of dilute solution (water) in order to obtain a 20% KOH solution. Pounds of water can be changed to gallons by dividing by 8.32 lb./gal.
EXAMPLE 2: Diluting a KOH Solution
Problem How many gallons of water must be added to 2,000 gallons of liquid caustic potash in order to obtain a 29% KOH solution? The KOH is found to have a specific gravity of 1.45 at 20°C.	Solution Refer to the Specific Gravities Table and find that a 20°C caustic potash solution with a specific gravity of 1.45 contains 45% KOH by weight. On the Dilution Chart, follow the 29% line vertically until it intersects line B and read horizontally left and right from the point of intersection. 35.6 lbs. of water must be added to 64.4 lbs. of 45% KOH. Divide each number by its density (in lbs./gal.) to change from pounds to gallons and then divide the resulting numbers to obtain the number of gallons of water to be added to each gallon of 45% KOH.
35.6/8.32=4.28; 64.4/12.09=5.33 4.28/5.33=0.803 gal.water/gal.45% KOH
EXAMPLE 3: Determining the Final Volume of a KOH Solution
Problem After dilution, what will be the final volume at 20°C of the KOH solution in example 2?	Solution Due to the chemical nature of caustic potash, shrinkage occurs when KOH solutions are diluted with water so that the final volume is always less tan expected. The exact final volume may be calculated as follows: Determine the weight of the original (45% KOH) solution and the weight of water added by multiplying the number of gallons by the density (in lb./gal.). Add the weights together and divide by the density (in lb./gal.) of the diluted (29% KOH) solution.
(200 x 12.09) + (1606 x 8.32) = 37542 lb. (37542 lb.) / (10.63 lb./gal.) = 3532 gal. of 29% solution The final volume is actually 3532 gallons compared to the expected volume of 3606 gallons.
EXAMPLE 4: Strengthening a KOH Solution
Problem How many gallons of 45% KOH must be added to 1,000 gallons of 25% KOH in order to obtain a 30% KOH solution at 20°C?	Solution Follow the 30% line on the Dilution Chart vertically until it intersects line C. Read horizontally left and right from the point of intersection. 25 lbs. of 45% must be added to 75 lbs. of 25% in order to make a 30% KOH solution. Divide each number by its density (in lb./gal.) to change from pounds to gallons. Densities at 20°C can be obtained from chart 2. Divide the resulting numbers to obtain the number of gallons of 45% to be added to each gallon of 25%.
25/12.09=2.07; 75/10.12=7.41 2.07/7.41=0.279 gal.45% KOH/gal.25% KOH Since 1,000 gallons of 25% KOH are to be strengthened, multiply 0.279 by 1,000. 279 gallons of 45% KOH must be added to 1,000 gallons of 25% KOH in order to obtain a 30% solution.

Densities and Concentrations of aqueous caustic potash solutions at 20°C (68°F)
		Density of KOH Solutions			Amount of KOH in Solution
% KOH (by weight)	Specific Gravity	Pounds per Gallon	Degrees Baumé	Degrees Twaddell	Actual Concentrations (100% KOH basis)	International Caustic Potash (90% KOH basis)
2	1.01623	8.46	2.3	3.2	0.17	0.19
4	1.03437	8.61	4.8	6.8	0.34	0.38
6	1.05262	8.76	7.3	10.5	0.53	0.59
8	1.07106	8.91	9.6	14.2	0.71	0.79
10	1.08970	9.07	11.9	17.9	0.91	1.01
12	1.10855	9.22	14.2	21.7	0.91	1.01
14	1.12763	9.38	16.4	25.5	1.31	1.46
16	1.14694	9.54	18.6	29.4	1.53	1.70
18	1.16645	9.71	20.7	33.3	1.75	1.94
20	1.18617	9.87	22.8	37.2	1.97	2.19
22	1.20600	10.04	24.8	41.2	2.21	2.46
24	1.22614	10.20	26.8	45.2	2.45	2.72
26	1.24650	10.37	28.7	49.3	2.70	3.00
28	1.26712	10.54	30.6	53.4	2.95	3.28
30	1.28799	10.72	32.4	57.6	3.22	3.58
32	1.30913	10.89	34.2	61.8	3.48	3.87
34	1.33053	11.07	36.0	66.0	3.76	4.18
36	1.35219	11.25	37.8	70.4	4.05	4.50
38	1.37413	11.43	39.5	74.8	4.34	4.82
40	1.39634	11.62	41.2	79.3	4.65	5.17
42	1.4188	11.80	42.8	83.8	4.96	5.51
44	1.44164	11.99	44.4	88.3	5.28	5.88
45	1.45314	12.09	45.2	90.6	5.44	6.04
46	1.46477	12.19	46.0	92.9	5.61	6.23
48	1.48820	12.38	47.6	97.6	5.94	6.60
50	1.51211	12.58	49.1	102.4	6.29	6.99
52	1.53632	12.78	50.6	107.3	6.65	7.39

Boiling Points of aqueous caustic potash solutions
Temp. (°C)	% KOH (by weight)	Temp. (°C)	% KOH (by weight)
100	0.0	230	70.67
110	25.65	240	72.46
120	36.51	250	74.07
130	43.42	260	75.76
140	48.05	270	77.52
150	51.57	280	79.05
160	54.88	290	80.32
170	57.8	300	81.63
180	60.42	310	82.99
190	62.73	320	84.03
200	64.93	330	85.11
210	66.89	340	86.16
220	68.73

Solubility of caustic potash in water
Temperature (°C)	% KOH (by weight)	Solid Phase
-2.2	3.6	Ice
-20.7	18.4	Ice
-65.2	30.8	Ice
-36.2	26.6	KOH · 4H2O
-32.7	43.8	KOH · 4H2O
-33	44.4	KOH · 4H2O + KOH · 2H2O
-23.2	45.9	KOH · 2H2O
0	49.2	KOH · 2H2O
10	50.7	KOH · 2H2O
15	51.7	KOH · 2H2O
20	52.8	KOH · 2H2O
30	55.76	KOH · 2H2O
32.5	57.44	KOH · 2H2O + KOH · H2O
50	58.33	KOH · 2H2O + KOH · H2O
100	64.03	KOH · 2H2O
125	68.06	KOH · 2H2O
143	75.73	KOH · 2H2O

Specific Gravities of aqueous potash solutions at various temperatures and concentrations
% KOH (by wt.)	32°F 0°C	50°F 10°C	68°F 20°C	86°F 30°C	104°F 40°C	122°F 50°C	140°F 60°C	158°F 70°C
0	0.99982	0.99948	0.99800	0.99553	0.99219	0.98809	0.98330	0.97789
2	1.01927	1.01822	1.01623	1.01341	1.00985	1.00562	1.00076	0.99529
4	1.03849	1.03681	1.03437	1.03124	1.02749	1.02315	1.01822	1.01269
6	1.05773	1.05548	1.05262	1.04922	1.04528	1.04083	1.03583	1.03026
8	1.07706	1.07429	1.07106	1.06739	1.06329	1.05872	1.05366	1.04804
10	1.09650	1.09327	1.08970	1.08579	1.08153	1.07686	1.07174	1.06607
12	1.11607	1.11243	1.10855	1.10443	1.10002	1.09526	1.09008	1.08437
14	1.13576	1.13177	1.12763	1.12332	1.11877	1.11392	1.10868	1.10293
16	1.15557	1.15130	1.14694	1.14245	1.13779	1.13285	1.12756	1.12176
18	1.17546	1.17098	1.16645	1.16183	1.15706	1.15205	1.14670	1.14087
20	1.19542	1.19082	1.18617	1.18145	1.17659	1.17151	1.16610	1.16024
22	1.21532	1.21069	1.20600	1.20122	1.19630	1.19116	1.18570	1.17981
24	1.23575	1.23094	1.22614	1.22132	1.21635	1.21115	1.20565	1.19973
26	1.25642	1.25145	1.24650	1.24154	1.23651	1.23128	1.22576	1.21982
28	1.27730	1.27219	1.26712	1.26204	1.25691	1.25159	1.24602	1.24006
30	1.29840	1.29318	1.28799	1.28280	1.27758	1.27217	1.26653	1.26054
32	1.31973	1.31442	1.30913	1.30384	1.29852	1.29302	1.28733	1.28129
34	1.34132	1.33591	1.33053	1.32514	1.31974	1.31416	1.30840	1.30232
36	1.36314	1.35766	1.35219	1.34672	1.34124	1.33558	1.32976	1.32364
38	1.38524	1.37969	1.37413	1.36857	1.36303	1.35729	1.35141	1.34524
40	1.40765	1.40199	1.39634	1.39071	1.38510	1.37930	1.37335	1.36713
42	1.43037	1.42459	1.41884	1.41313	1.40747	1.40160	1.39560	1.38932
44	1.45347	1.44751	1.44164	1.43585	1.43015	1.42422	1.41817	1.41182
46	1.47700	1.47079	1.46477	1.45889	1.45315	1.44718	1.44108	1.43465
48	1.50097	1.49442	1.48820	1.48222	1.47645	1.47045	1.46431	1.45779
50	1.52565	1.51861	1.51211	1.50600	1.50022	1.49419	1.48802	1.48139