US2467324A

US2467324A - Reducing viscosity of cellulose nitrate with morpholine

Info

Publication number: US2467324A
Application number: US511185A
Authority: US
Inventors: Stewart B Luce
Original assignee: Monsanto Chemicals Ltd
Current assignee: Monsanto Chemicals Ltd; Monsanto Chemical Co
Priority date: 1943-11-20
Filing date: 1943-11-20
Publication date: 1949-04-12
Anticipated expiration: 1966-04-12

Description

Patented Apr. 12, 1949 REDUCKNG VISCOSITY OF CELLULOSE NITRATE WITH MORPHOLINE Stewart B. Luce, Springfield, Mass., assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application November 20, 1943, Serial No. 511,185

8 Claims. (Cl. 260-223) This invention relates to the reduction in viscosity of cellulose nitrate.

It is known that the viscosity of cellulose nitrate may be reduced, for example, by steam digestion under high pressure. However, such methods require complicated and expensive apparatus to insure safe operating conditions. Other prior processes lead to products possessing poor color and/or requiring expensive purifrcation.

An object of this invention is to provide an improved method for reducing the viscosity of cellulose nitrate. A further object of this invention is to provide a process for reducing the viscosity of cellulose nitrate with substantially no discoloration or decomposition thereof. Still another object is to provide a method for reducing the viscosity of cellulose nitrate at moderate temperatures and pressures thereby eliminating explosive hazards of high temperature and pressure methods.

According to the present invention, the viscosity of cellulose nitrate is reduced by treatment with a 'morpholine compound. By operating according to this invention the viscosity of cellulose nitrate may be reduced under far less hazardous conditions than have characterized certain prior methods and/or other advantageous results may be obtained.

By a morpholine compound is meant a compound possessing the structural formula or derivative thereof wherein one or more of the hydrogens may be substituted by monovalent organic radicals, for example, aryl radicals such as phenyl, naphthyl, halogeno-phenyl (chlorophenyl), hydroxy phenyl, alkoxy phen'yl; al-

kylated aryl radicals such as toluyl; alkyl radia desirable. The duration of the treatment depends on the degree of viscosity reduction desired in the cellulose nitrate and the temperatures and other conditions employed. In general, from 0.1% to 10% by weight of a morpholine compound is employed, based on the amount of cellulose nitrate. According to a preferred embodiment from 0.5% to 3% of a morpholine compound is employed.

The cellulose nitrate employed may be prepared from wood pulp, cotton linters or other suitable source of cellulose. According to my invention the cellulose nitrate may be treated in solution or in the solid state when in the form of fibres or other finely divided form. The viscosity of the cellulose nitrate employed may be widely varied. In fact a particularly advantageous feature of this invention resides in the fact that cellulose nitrate of high viscosity, for example, 1000 seconds viscosity or more may be readily made available for use in lacquers, plastics, etc., wherein low viscosities are necessary, for example 0.25- seconds, while maintaining substantially the nitrogen content, color, etc., of the original material. This makes possible material savings in the cost of the final product since, as is known, the initial preparation of high viscosity cellulose nitrate is far more economical than that of low viscosity cellulose nitrate.

By proper combination of the conditions of treatment of cellulose nitrate with a morpholine compound according to this invention, products may be prepared having varying viscosities, for example, as low as 0.25 second or even lower.

The following are specific examples illustrative of the present invention but not limitative thereof.

The stability and viscosity values given in the examples are determined in accordance with the A. S. T. M. D301-33 methods entitled Specifications and Tests for Soluble Nitrocellulose.

Example I 40 grams of cellulose nitrate having a nitrogen content of 12%, a viscosity of 49.6 seconds and a stability of over 25 minutes were slurried with 500 cc. of water and 0.4 gram of morpholine and the resulting slurry heated at atmospheric pressure for 12 hours at -95 C. The slurry was then centrifuged and the separated cellulose nitrate washed and. dried. The product had a viscosity of 15.4 seconds.

Ewample II 40 grams of cellulose nitrate like that of Example I, except that the viscosity was 40 seconds, were slurried with 500 cc. of water and 1 gram of morpholine. The resulting slurry was heated for 4 hours at 90-95 C. and at atmospheric pressure and was then centrifuged, and the separated cellulose nitrate washed and dried. The resulting cellulose nitrate had a viscosity of 0.6 second.

Example III A slurry containing 100 parts of cellulose nitrate like that of Example Lbut having a viscosity of 8.6 seconds, 2.5 parts of morpholine and 1250 parts of water was heated at 90-95 C. at atmospheric pressure, then centrifuged, and the separated cellulose nitrate washed and dried. By varying the time of reaction, varying degrees of viscosity reduction were obtained as shown in the following table:

. 1 Duration I of Heating Viscosity Hours Seconds Example IV Example V A slurry containing 100 parts of cellulose nitrate like that used in EXample I, but having a viscosity of 19.3 seconds, 2.5 parts of morpholine and 1250 parts of water was heated for 4 hours at 9095 C. and at atmospheric pressure. It was then centrifuged, washed and the separated cellulose nitrate bleached as 'in Example IV to yield a cellulose nitrate of pale color having a viscosity of 0.9 second and a nitrogen content of 11.59%.

In contrast to the foregoing a second sample of the same cellulose'nitrate heated for 2 hours at90- 95 C. with 2% of its weight of ammonia in aqueous solution produced a dark brown cellulose nitrate having a viscosity of 0.6 second.

Example VI 10 grams of cellulose nitrate like that of Example I, but having a viscosity of 40.1 seconds, were placed in a glass tube, 30 cc. of water and 0.05 gram of morpholine were then added and the tube was sealed. The sealed tube was then placed in a capped iron tube and the-whole placed in a heated circulating oil bath and then heated at'135 C. for 4 hours. After cooling, the glass tube was opened, the contents centrifuged and the separated cellulose nitrate washed and dried. The product had a viscosity of 0.18 second and a nitrogen content of 11.8%.

Example VII 10 grams of cellulose nitrate'like that of Example I, but having a'viscosity of-1004 seconds 4 were heated as in Example VI in admixture with 0.15 gram of morpholine and 35 cc. of water at C. in a sealed tube for 4 hours. The product was centrifuged and the separated cellulose nitrate washed and dried. The resultant cellulose nitrate had a viscosity'0f-0.18 second and a nitrogen content of 11.5%.

It is found that products prepared as described in the above examples require no stabilization treatment to prevent rapid discoloration or decrease in viscosity on aging. This is in contrast to products prepared, for example, by treatment with ammonia or pyridine, which require extensive treatment, for example, with boiling water or chemical reagents to provide a, stabilized product that will not rapidly discolor or decrease in viscosity on aging.

Cellulose nitrate initially having a stability of not over 25 minutes continues to meet this stability requirement after treatment according to this invention, as exemplified by Examples I-VII. In fact, unstabilized cellulose nitrate may even be rendered substantially stable according to the A. S. T. M. 13301-33 test conditions as a result of the viscosity"reduction treatment according to this invention.

It is to be further noted from the examples that the cellulose nitrate may be bleached after the viscosity has been reduced, by the procedures well known in the industry to obtain especially light colored products.

In place of cellulose nitrate having a nitrogen content of 12% which is normally used for making nitrocellulose lacquers, coatings, etc., cellulose nitrate containing other percentages of nitrogen, for example, from 10.5% to 12.5% may be used. Cellulose nitrate containing about 11% nitrogen may be reduced in viscosity'by the process of this invention to yield materials especially useful, for example, in extrusion and other processes for forming cellulose nitrate plastic compositions.

Other reaction media than water may be used according to the process of this invention. Thus, a slurry may be made using a liquid non-solvent for the cellulose nitrate such as, for example, toluol, hexane, carbon tetrachloride, etc. When desired, the reaction may be carried out insolu- :tion by substituting for the Water shown in the above examples an active solvent for cellulose nitrate such as, for example, aliphatic alcohols including methanol, ethanol, propanol, isopropanol, butanoi, isobutanol, etc., as Well as ketones including acetone, methyl ethyl ketone, diethyl ketone, etc. Varying degrees of dilution of the slurry or solution may be employed. Treatment in solution is especially desirable when it is desired to prepare low viscosity cellulose nitrate from scrap cellulose nitrate plastic.

What is claimed is:

1. A process for reducingthe-viscosity of cellulose nitrate which comprises treating cellulose nitrate with morpholine.

2. A process for reducing the viscosity of cellulose nitrate which comprises treating cellulose nitrate in a slurry with morpholine.

3. A process for reducing the viscosity of cellulose nitrate which comprises treating cellulose nitrate in solution with morpholine.

4. A process for reducing the-viscosity of cellulose nitrate which comprises treating cellulose nitrate in an aqueous slurry with morpholine.

5. A process for reducing the viscosity of cellulose nitrate which comprises "treating 'anaqueous slurry containing cellulose nitrate with morphollne at 20-150 C.

6. A process for reducing the viscosity of cellulose nitrate which comprises heating an aqueous slurry containing cellulose nitrate and morpholine at a pressure between 1 and 6 atmospheres.

7. A process for reducing the viscosity of cellulose nitrate which comprises treating an aqueous slurry containing cellulose nitrate and 0.1% to 10.0% by weight of morpholine based on the cellulose nitrate, at 20150 C. and at 1 to 6 atmospheres pressure.

8. In the process of reducing the viscositysof cellulose nitrate, the steps comprising heating an aqueous slurry of cellulose nitrate in finely divided 15 6 form and 0.1 to about 10% by weight of morpholine based on the cellulose nitrate and then separating the finely divided cellulose nitrate from said slurry.

STEWART B. LUCE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,648,509 Seel Nov. 8, 1927 1,9461967 Eskew Feb. 6, 1934 2,292,332 D'Alelio Aug. 4, 1942