Polymerization of ethylene

Claim 2

In a process for polymerizing ethylene to produce normally solid polymers of ethylene in a tubular reactor at a pressure in the range of 5,000 psi to 60,000 psi at a temperature in the range of 40* C to 300*C in the presence of oxygen as initiator for the polymerization introduced at the inlet end of said tubular reactor with an ethylene feed material comprising at least 89 percent by weight of gaseous ethylene to be polymerized and wherein the reaction temperature rises to a peak within the range from about 200* to about 300*C, the improvement comprising injecting additional feed material comprising at least 89 percent by weight of gaseous ethylene and oxygen at at least one point into said tubular reactor down-stream from the inlet end of said tubular reactor where a reaction temperature peak occurs, said additional feed material and oxygen being injected at sub-stantially the same point and the gaseous ethylene in said injected feed material being employed as the coolant at a temperature and in an amount sufficient to maintain the temperature of the polymerization mixture at the point of injection below said peak temperature but above the temperature required for the initiation of ethylene polymerization by said oxygen so as to obtain an increase in conversion of ethylene to polymers of ethylene.

Claim 3

In a process for polymerizing ethylene to produce normally solid polymers of ethylene in a tubular reactor at a pressure in the range of 5,000 psi to 60,000 psi at a temperature in the range of 40* C to 300* C in the presence of a peroxide as initiator for the polymerization introduced at the inlet end of said tubular reactor with an ethylene feed material comprising at least 89 percent by weight of gaseous ethylene to be polymerized and wherein the reaction temperature rises to a peak within the range from about 200* to about 300* C, the improvement comprising injecting additional feed material comprising at least 89 percent by weight of gaseous ethylene and peroxide at at least one point into said tubular reactor downstream from the inlet end of said tubular reactor where a reaction temperature peak occurs, said addition feed material and peroxide being injected at substantially the same point and the gaseous ethylene in said injected feed material being employed as the coolant at a temperature and in an amount sufficient to maintain the temperature of the polymerization mixture at the point of injection below said peak temperature but above the temperature required for the initiation of ethylene polymerization by said peroxide so as to obtain an increase in conversion of ethylene to polymers of ethylene.

Claim 4

In a process for polymerizing ethylene to produce normally solid polymers of ethylene in a tubular reactor having a length-to-diameter ratio greater than 1000: at a pressure of 30,000 psi and a temperature of 225* C in the presence of 42 parts of oxygen per million parts of gaseous ethylene feed to said tubular reactor as an initiator for the polymerization introduced at the inlet end of said tubular reactor with gaseous ethylene containing 2.5 percent by weight of propane, the improvement comprising injecting additional gaseous ethylene containing 2.5 percent propane in admixture with 42 parts of oxygen per million parts of gaseous ethylene feed at a temperature of 40* C into said tubular reactor at two additional points spaced downstream from the inlet end of said tubular reactor 20 and 40 percent, respectively, of the total length of said tubular reactor, the ratio of the ethylene introduced at the inlet end to the ethylene injeCted at said two additional downstream points in said tubular reactor being 1:0. 4:0. 6 by weight and the total feed rate to said tubular reactor being 152 lb/hr.

Claim 5

In a process for polymerizing ethylene to produce normally solid polymers of ethylene in a tubular reactor at high pressure and elevated temperatures in the presence of a free-radical-generating initiator for the polymerization and up to 10% by weight of the ethylene of a chain-transfer agent introduced at the inlet of said tubular reactor with gaseous ethylene to be polymerized and wherein the reaction temperature rises to a peak within the range from about 200* to about 300*C, the improvement comprising injecting gaseous ethylene and initiator and chain-transfer agent at at least one point into said tubular reactor downstream from the inlet of said tubular reactor where a reaction temperature peak occurs, said gaseous ethylene, initiator and chain-transfer agent being injected at substantially the same point, and said injected gaseous ethylene being employed as the coolant at a temperature and in an amount sufficient to maintain the temperature of the polymerization mixture at the point of injection below said peak temperature but above the temperature required for the initiation of ethylene polymerization by said initiator so as to obtain an increase in conversion of ethylene to polymers of ethylene.

Claim 6

The process of claim 6 wherein the chain-transfer agent is selected from the group consisting of saturated aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, acetone, hydrogen, carbon dioxide and phenolic compounds.

Claim 7

In a process for polymerizing ethylene to produce normally solid polymers of ethylene in a tubular reactor at high pressure and elevated temperatures in the presence of from about 0.0005 percent to about 2 percent of the total weight of material charged to said tubular reactor of a free-radical-generating initiator and from about 0.5 percent to about 10% by weight based on ethylene of a chain-transfer agent introduced at the inlet end of said tubular reactor with gaseous ethylene to be poly-merized and wherein the reaction temperature rises to a peak within the range from about 200* to about 300* C, the improvement comprising injecting additional gaseous ethylene and from about 0.0005 percent to about 2 percent of the total weight of material charged to said tubular reactor of said initiator and from about 0.5 to about 10 percent by weight based on ethylene of a chain-transfer agent at at least one point into said tubular reactor downstream from the inlet end of said tubular reactor where a reaction temperature peak occurs, said gaseous ethylene, initiator and chain-transfer agent being injected at substantially the same point, and the gaseous ethylene in said injected gaseous ethylene, initiator and chain-transfer agent being employed as the coolant at a temperature and in an amount sufficient to maintain the temperature of the polymerization mixture at the point of injection below said peak temperature but above the temperature required for the initiation of ethylene polymerization by said initiator so as to obtain an increase in conversion of ethylene to polymers of ethylene.

Claim 8

In a process for polymerizing ethylene to produce normally solid polymers of ethylene in a tubular reactor at a pressure in the range of 5,000 psi to 60,000 psi at a temperature in the range of 40*C to 300*C in the presence of from about 0.0005 percent to about 2 percent of the total weight of material charged to said tubular reactor of oxygen as initiator for the polymerization and from about 0.5 percent to about 10 percent by weight based on ethylene of a chain-transfer agent introduced at the inlet end of said tubular reactor with gaseous ethylene to be polymerized and wherein the reaction temperature rises to a peak within the raNge from about 200* to about 300* C, the improvement comprising injecting additional gaseous ethylene and from about 0.0005 percent to about 2 percent of the total weight of material charged to said tubular reactor of oxygen and from about 0.5 percent to about 10 percent by weight based on ethylene of a chain-transfer agent at at least one point into said tubular reactor downstream from the inlet end of said tubular reactor where a reaction temperature peak occurs, said additional gaseous ethylene and oxygen and chain-transfer agent being injected at substantially the same point, and the gaseous ethylene in said injected gaseous ethylene, oxygen and chain-transfer agent being employed as the coolant at a temperature and in an amount sufficient to maintain the temperature of the polymerization mixture at the point of injection below said peak temperature but above the temperature required for the initiation of ethylene polymerization by said oxygen so as to obtain an increase in conversion of ethylene to polymers of ethylene.

Claim 9

In a process for polymerizing ethylene to produce normally solid polymers of ethylene in a tubular reactor at a pressure in the range of 5,000 psi to 60,000 psi at a temperature in the range of 40*C to 300*C in the presence of from about 0.0005 percent to about 2 percent of the total weight of material charged to said tubular reactor of a peroxide as initiator for the polymerization and from about 0.5 percent to about 10 percent by weight based on ethylene of a chain-transfer agent introduced at the inlet end of said tubular reactor with gaseous ethylene to be polymerized and wherein the reaction temperature rises to a peak within the range from about 200* to about 300*C, the improvement comprising injecting additional gaseous ethylene and from about 0.0005 percent to about 2 percent of the total weight of material charged to said tubular reactor of a peroxide and from about 0.5 percent to about 10 percent by weight based on ethylene of a chain-transfer agent at at least one point into said tubular reactor downstream from the inlet end of said tubular reactor where a reaction temperature peak occurs, said additional gaseous ethylene and peroxide and chain-transfer agent being injected at substantially the same point, and the gaseous ethylene in said additional gaseous ethylene, peroxide and chain-transfer agent being employed as the coolant at a temperature and in an amount sufficient to maintain the temperature of the polymerization mixture at the point of injection below said peak reaction temperature but above the temperature required for the initiation of ethylene polymerization by said peroxide so as to obtain an increase in conversion of ethylene to polymers of ethylene.