Manufacture of methylolalkanes

1. A method of making a methylolalkane from formaldehyde and a C 2 or higher condensable aldehyde in a multistage process comprising:

(a) providing a formaldehyde containing stream to a tubular reaction system with a plurality of successive reaction stages;

(b) adding a C 2 or higher condensible aldehyde and optionally a base to the formaldehyde containing stream wherein at least one of the C 2 or higher condensible aldehyde or base are added to the formaldehyde containing stream at a plurality of successive feed points to provide a production stream which is progressively provided with additional C 2 or higher condensible aldehyde or base as the production stream advances through the successive reaction stages; and

(c) converting the C 2 or higher condensible aldehyde and formaldehyde to a methylolalkane.

2. The method according to claim 1 , wherein the C 2 or higher condensible aldehyde is added to the formaldehyde containing stream at a plurality of successive feed points to provide a production stream which is progressively provided with additional C 2 or higher condensible aldehyde as the production stream advances through the successive reaction stages.

3. The method according to claim 1 , wherein the methylolalkane is trimethylolpropane and the C 2 or higher condensible aldehyde is n-butyraldehyde.

4. The method according to claim 1 , wherein the methylolalkane is neopentyl glycol and the C 2 or higher condensible aldehyde is isobutyraldehyde.

5. The method according to claim 1 , wherein base is added to the formaldehyde containing stream at a plurality of successive feed points to provide a production stream which is progressively provided with additional base as the production stream advances through the successive reaction stages.

6. The method according to claim 5 , wherein said base is an inorganic base selected from potassium hydroxide, calcium hydroxide and sodium hydroxide.

7. The method according to claim 1 , wherein said tubular reaction system has at least 3 stages.

8. The method according to claim 1 , comprising adding the C 2 or higher condensible aldehyde and an inorganic base to the formaldehyde containing stream at a plurality of successive feed points to provide a production stream which is progressively provided with additional C 2 or higher condensible aldehyde and inorganic base as the production stream advances through the successive reaction stages.

9. The method according to claims 8 , wherein said inorganic base is selected from potassium hydroxide, calcium hydroxide and sodium hydroxide.

10. The method according to claim 8 , wherein said C 2 or higher condensible aldehyde is added in a fixed proportion with inorganic base at said plurality of successive feed points to provide a production stream which is progressively provided with additional C 2 or higher condensible aldehyde as the production stream advances through the successive reaction stages.

11. The method according to claim 10 , wherein said C 2 or higher condensible aldehyde and inorganic base are provided in an upstream feed point in larger amounts relative to amounts provided in a downstream feed point.

12. The method according to claim 8 , wherein said inorganic base is provided in a downstream feed point in a larger amount relative to an amount provided in an upstream feed point to provide a production stream which is provided with inorganic base at higher levels in a later stage as compared with levels of inorganic base in an stage.

13. The method according to claim 1 , wherein the temperature of the production stream is maintained between 30° C. and 75° C.

14. A multistage tubular reaction system for preparing methylol derivatives of a C 2 or higher condensible aldehyde comprising:

(a) a tubular reaction system with a plurality of successive reactor stages comprising a plurality of reaction tubes cooled with a coolant in order to maintain a desired temperature;

(b) a reaction system inlet adapted to provide a formaldehyde containing stream to the tubular reaction system; and

(c) a plurality of feed ports adapted to provide at least one of the C 2 or higher condensible aldehyde or a base to the formaldehyde containing stream at a plurality of successive feed points to provide a production stream which is progressively provided with additional C 2 or higher condensible aldehyde or base as the production stream advances through successive reaction stages,

wherein the temperature of the production stream is maintained between 30° C. and 75° C.

15. The multistage tubular reaction system for preparing methylol derivatives of a C 2 or higher condensible aldehyde according to claim 14 , wherein the reaction system comprises a plurality of reaction tubes of a jacketed construction with an outer shell, an annular cooling channel and an inner reaction tube defining a reaction zone and wherein the annular cooling channel receives coolant.

16. A multistage tubular reaction system for preparing methylol derivatives of a C 2 or higher condensible aldehyde comprising:

(a) a tubular reaction system with a plurality of successive reactor stages comprising a plurality of reaction tubes cooled with a coolant in order to maintain a desired temperature;

(b) a reaction system inlet adapted to provide a formaldehyde containing stream to the tubular reaction system; and

(c) a plurality of feed ports adapted to provide at least one of the C 2 or higher condensible aldehyde or a base to the formaldehyde containing stream at a plurality of successive feed points to provide a production stream which is progressively provided with additional C 2 or higher condensible aldehyde or base as the production stream advances through successive reaction stages,

wherein the reaction system comprises a plurality of reaction tubes of a jacketed construction with an outer shell, an annular cooling channel and an inner reaction tube defining a reaction zone and wherein the annular cooling channel receives coolant.