Method for the determination of an acid or a base in a non-aqueous liquid

• US 20010046711A1
• Filed: 03/26/2001
• Published: 11/29/2001
• Est. Priority Date: 03/29/2000
• Status: Abandoned Application

• Current Assignee: Phan Van Pham, Purnendu K. Dasgupta, Raymond Alfonsas Plepys, Sofia Galanis Hohnholt
• Original Assignee: Phan Van Pham, Purnendu K. Dasgupta, Raymond Alfonsas Plepys, Sofia Galanis Hohnholt
• Inventors: Pham, Phan van, Plepys, Raymond Alfonsas, Hohnholt, Sofia Galanis, Dasgupta, Purnendu K.
• Application Number:
  US09/817,686
• Publication Number:
  US 20010046711A1
• Time in Patent Office: Days
• US Class Current: 436/100
• CPC Class Codes: G01N 21/80 Indicating pH value
• CPC Class Codes: G01N 31/221 for investigating pH value
• CPC Class Codes: G01N 35/085 Flow Injection Analysis
• CPC Class Codes: Y10T 436/15 Inorganic acid or base [e.g. , hcl, sulfuric acid, etc. ]

Abstract

A chemical analysis method for the determination of a base (or an acid) in a nonaqueous liquid (such as a polyol) which method can be automated and placed on-line in a chemical production facility. The instant invention includes two steps. The first step is to mix an acid-base indicator (for example, bromocresol green) with the non-aqueous liquid to produce a colored reaction product between the base or acid and the acid-base indicator. The second step is to determine the intensity of the color of the colored product.

Claims

1. A chemical analysis method for the determination of a base in a non-aqueous liquid, comprising the steps of:

(a) dispersing an acid-base indicator with the non-aqueous liquid to produce a colored product;

(b) determining the intensity of the color of the colored product.

5. The method of

claim 1

, wherein in step (b) the width of the intensity of the color of the concentration dispersion of the colored product in the non-aqueous liquid is determined at a preselected intensity.

2. A chemical analysis method for the determination of a base in a non-aqueous liquid, comprising the steps of:

(a) dispersing an acid-base indicator with the non-aqueous liquid to produce a concentration dispersion of the acid-base indicator in the non-aqueous liquid to produce a concentration dispersion of a colored product in the non-aqueous liquid; and

(b) determining the intensity of the color of the concentration dispersion of the colored product in the non-aqueous liquid.

3. The method of

claim 2

, wherein in step (b) the maximum intensity of the color of the concentration dispersion of the colored product in the non-aqueous liquid is determined.

4. The method of

claim 2

, wherein in step (b) the intensity of the color of the concentration dispersion of the colored product in the non-aqueous liquid is integrated across a region of the concentration dispersion of the colored product in the non-aqueous liquid.

6. The chemical analysis method of

claim 2

, wherein the base comprises an alkali metal hydroxide.

7. The chemical analysis method of

claim 6

, wherein the alkali metal hydroxide comprises potassium hydroxide.

8. The chemical analysis method of

claim 7

, wherein the acid-base indicator comprises bromocresol green in the free acid form.

9. The chemical analysis method of

claim 2

, wherein in step (a) the acid-base indicator is dispersed as a solution containing the acid-base indicator and a Bronsted acid.

10. The chemical analysis method of

claim 7

, wherein in step (a) the acid-base indicator comprises bromocresol green in the free acid form dispersed as a solution comprising 2-propanol, the bromocresol green and hydrochloric acid.

11. The chemical analysis method of

claim 2

, wherein the source of the nonaqueous liquid is a chemical process vessel or conduit, further comprising step (c) directing the concentration dispersion of the colored product in the non-aqueous liquid of step (b) back into a chemical process vessel or conduit.

12. The chemical analysis method of

claim 11

, wherein the non-aqueous liquid is a polyol.

13. The chemical analysis method of

claim 11

, wherein the non-aqueous liquid is a polyether polyol.

14. A chemical analysis method for the determination of an acid in a nonaqueous liquid, comprising the steps of:

(a) dispersing an acid-base indicator with the non-aqueous liquid to produce a colored product; and

(b) determining the intensity of the color of the colored product.

25. The chemical analysis method of

claim 14

, wherein the non-aqueous liquid is a polyol.

26. The chemical analysis method of

claim 14

, wherein the non-aqueous liquid is a polyether polyol.

15. A chemical analysis method for the determination of an acid in a nonaqueous liquid, comprising the steps of:

(a) dispersing an acid-base indicator with the non-aqueous liquid to produce a concentration dispersion of the acid-base indicator in the non-aqueous liquid to produce a concentration dispersion of a colored product in the non-aqueous liquid; and

(b) determining the intensity of the color of the concentration dispersion of the colored product in the non-aqueous liquid.

16. The method of

claim 15

, wherein in step (b) the maximum intensity of the color of the concentration dispersion of the colored product in the non-aqueous liquid is determined.

17. The method of

claim 15

, wherein in step (b) the intensity of the color of the concentration dispersion of the colored product in the non-aqueous liquid is integrated across a region of the concentration dispersion of the colored product in the non-aqueous liquid.

18. The method of

claim 15

, wherein in step (b) the width of the intensity of the color of the concentration dispersion of the colored product in the plolyether non-aqueous liquid is determined at a preselected intensity.

19. The chemical analysis method of

claim 15

, wherein the acid comprises a Bronsted acid.

20. The chemical analysis method of

claim 19

, wherein the Bronstead acid comprises sulfuric acid.

21. The chemical analysis method of

claim 20

, wherein the acid base indicator comprises bromocresol green in the sodium ion form.

22. The chemical analysis method of

claim 15

, wherein in step (a) the acid-base indicator is dispersed as a solution containing the acid-base indicator and a Bronsted base.

23. The chemical analysis method of

claim 20

, wherein in step (a) the acid-base indicator is bromocresol green in the sodium ion form dispersed as a solution comprising 2-propanol, the bromocresol green and sodium hydroxide.

24. The chemical analysis method of

claim 15

, wherein the source of the nonaqueous liquid is a chemical process vessel or conduit, further comprising step (c) directing the concentration dispersion of the colored product in the non-aqueous liquid of step (b) back into a chemical process vessel or conduit.